Patent Application
20110139399
1. Technical Field
The present invention relates primarily to a heater unit used to heat a glass substrate or a semiconductor substrate for a flat panel display, a heating and cooling device including this heater unit, and a manufacturing or inspection apparatus equipped with these devices; the present invention particularly relates to a heat treatment apparatus used in a photolithography step or a prober inspection step, or to a heat treatment apparatus used in the final inspection step of a semiconductor substrate.
2. Related Background Art
Many apparatuses have been developed which can heat-treat an object to be heated when it is placed thereon, and there are heating and cooling devices composed of aluminum or another metal or a ceramic, for example, see Japanese Laid-open Patent Application No. 11-040330 and Japanese Laid-open Patent Application No. 2007-150294.
Among these apparatuses, a heater used in the manufacturing step or inspection step of a semiconductor apparatus or a flat panel display needs to have uniformity of temperature distribution (also referred to as uniform heat properties hereinbelow) particularly in the surface on which the object to be heated is placed. Specific examples of the aforementioned steps include heat-curing of a photosensitive resin, heat-firing of a low-dielectric insulating film such as a low-κ film, CVD film formation for forming wiring, an insulating layer, or the like, etching, and other steps. Otherwise, to perform inspection at the desired temperature, the heater used to raise the temperature of the substrate must have the same characteristics.
In the production of these semiconductor apparatuses and flat panel displays, a goal is to reduce the price of the products by large-scale production by continuous operation, and because of this, there is demand for shortening the takt time with the manufacturing apparatuses and inspection apparatuses. To obtain a high throughput with one apparatus, the treatment time of the heat treatment step itself of the object being treated must of course be shortened, the object being maintained at a constant temperature and subjected to a predetermined treatment, and what also must be shortened is the time needed to change the set temperature of the heater (temperature increasing time, cooling time) along with changes in the treatment conditions.
To resolve the problems described above, the inventors have already invented a heater for manufacturing a semiconductor apparatus. This heater is configured so that a cooling plate and a heater plate which have desired heat capacities can be separated from each other and brought in contact with each other. With this heater, during heating, the cooling plate is rapidly increased in temperature by being separated from the heater plate, and during cooling, the cooling plate is brought in contact with the heated heater plate, whereby the placement stand provided to the heater plate and the object to be heated placed on this placement stand can be rapidly cooled (see Japanese Laid-open Patent Application No. 2004-014655). Thereby, it has been possible to shorten the required time of the entire production process.
The heater plate 2 can be configured, for example, from a placement stand 50 on which a semiconductor substrate is placed, and heating element circuit 51 arranged in, e.g., a coiled configuration, and disposed on the underside of the placement stand 50. The heating element circuit 51 may be formed by tungsten metallization. The heating element circuit 51 is insulated by being coated by an electrical insulating film (not shown).
Referring again to
Next, referring to
After the heat treatment described above has been repeated and a predetermined quantity of objects to be heated S have been heat treated, the temperature conditions are changed in order to perform a heat treatment for a process separate from the heat treatment described above. When the temperature condition changes are changes that cause the temperature to increase, the temperature may be changed merely by changing the energy supply conditions in the state shown in
At this time, cooling water or another refrigerant may be caused to flow through the refrigerant flow passage (not shown in
However, since recently there has been a demand for greater precision and improved throughput, there is also demand for faster temperature increasing rates and cooling rates while maintaining highly uniform heat properties in the placement surface of the heater plate. To achieve this, it is preferable that the heat capacity of the placement stand be reduced as much as possible, i.e., that the placement stand be reduced in weight and thinned. However, when the placement stand is formed from a metal plate, the metal has low rigidity; therefore, the metal bends when thinned and warps when increased in temperature, and it has not been possible to maintain satisfactory uniform heat properties. When the placement stand is formed from a ceramic plate, the ceramic has comparatively high rigidity and can therefore be made thinner, but when the ceramic is thinned it is difficult to ensure uniform heat properties, the ceramic readily cracks, and the ceramic has not withstood practical application.
The present invention was devised in view of problems such as those described above, and an object thereof is to increase the rates of temperature increase and temperature decrease without compromising the uniform heat properties in the placement surface, or while maintaining more highly uniform heat properties than in conventional practice. By accomplishing this object, particularly in the process of manufacturing semiconductor apparatuses or flat panel displays, the heating process under subsequent conditions can be carried out quickly after changes have been made to the temperature conditions so as to increase or reduce the temperature. By achieving highly uniform heat properties in the placement surface, it is possible to reduce discrepancies in the film thickness or line width during the photolithography step, for example, during the semiconductor manufacturing process.
In other words, an object is to improve the productivity, performance, yield rate, and reliability of semiconductor apparatuses and flat panel display apparatuses manufactured and inspected by this heat treatment step, by reducing temperature discrepancies in the placement surface during the heat treatment step and shortening the time needed to increase the temperature and change the cooling temperature.
To achieve the objects described above, the heater unit provided by the present invention is a heater unit comprising a first uniform heat plate having a placement surface for placing a substrate, a second uniform heat plate for supporting the first uniform heat plate, and at least one layer of a insulated resistance heating element provided between the first uniform heat plate and the second uniform heat plate; the first uniform heat plate of the heater unit having a first thermal conductivity K1 and a first Young's modulus Y1, and the second uniform heat plate of the heater unit have a second thermal conductivity K2 and a second Young's modulus Y2, where K1≠K2 and Y1≠Y2.
Another embodiment of the present invention is a heater unit wherein the first uniform heat plate is formed of a metal, the second uniform heat plate is formed of a ceramic or a metal-ceramic composite material, the relationship between the thermal conductivity of each of the first uniform heat plate and the second uniform heat plate, is K1>K2, and the relationship between the Young's modulus of each of the first uniform heat plate and the second uniform heat plate is Y2>Y1.
Another embodiment of the present invention is a heater unit wherein the total of the thicknesses of the first uniform heat plate and the second uniform heat plate is 1/40 or less of the diameter of the first uniform heat plate, the insulated resistance heating element is integrally formed using a resistance heating element and a heat-resistant insulator, the heat-resistant insulator is a heat-resistant insulator whose primary constituent is polyimide or Teflon, or both, and the thickness of the insulated resistance heating element is 0.5 mm or less.
Another embodiment of the present invention is a heater unit wherein the first uniform heat plate and the second uniform heat plate are both 1 mm or greater in thickness.
Another embodiment of the present invention is a heater unit where the second uniform heat plate has a surface in contact with the insulated resistance heating element and the surface has a flatness that is 100 μm or less.
Another embodiment of the present invention is a heater unit wherein the second uniform heat plate has a surface in contact with the insulated resistance heating element, the surface includes an upwardly concave shape.
Another embodiment of the present invention is a heater unit wherein the first uniform heat plate and the second uniform heat plate are bonded together so that their opposing surfaces are movable relative to each other in substantially parallel directions, and one of the first uniform heat plate and the second uniform heat plate is formed of metal and is subjected to processing providing flexibility on at least one side, while the other of the first uniform heat plate and the second uniform heat plate is formed of a ceramic or a metal-ceramic composite material.
Another embodiment of the present invention is a heater unit wherein the one of the first uniform heat plate and the second uniform heat plate comprises a metal with a first thickness and the other of the first uniform heat plate and the second uniform heat plate comprises a ceramic or a metal-ceramic composite material with a second thickness, the first thickness being equal to or less than the second thickness.
Another embodiment of the present invention is a heater unit wherein the second uniform heat plate includes a surface in contact with the insulated resistance heating element, the surface having a flatness that is 100 μm or less.
Another embodiment of the present invention is a heater unit wherein the second uniform heat plate includes a surface in contact with the insulated resistance heating element, the surface having an upwardly concave shape.
Another embodiment of the present invention is a heater unit wherein the bond allowing the relative movement is a bond achieved by vacuum-suction means or a bond achieved by bonding means including a combination of screws and bearings.
Another embodiment of the present invention is a heater unit further comprising a vacuum-sealing member used as the vacuum-suction means.
Another embodiment of the present invention is a heater unit wherein the vacuum-sealing member is disposed in an external peripheral vicinity of the first uniform heat plate and the second uniform heat plate.
Another embodiment of the present invention is a heating and cooling device comprising the heater unit of the previously described embodiments, and a mobile cooling plate provided underneath the heater unit.
Another embodiment of the present invention is a manufacturing or inspection apparatus for glass substrates or semiconductor substrates for flat panel displays, comprising the heater unit of the previously described embodiments.
Another embodiment of the present invention is a manufacturing or inspection apparatus for glass substrates or semiconductor substrates for flat panel displays, comprising the heating and cooling device of the previously described embodiments.
According to the present invention, the flatness of the placement stand does not change over time, and either uniform heat properties similar to conventional practice can be maintained, or more highly uniform heat properties than in conventional practice can be maintained. Furthermore, according to the present invention, changes in flatness during temperature increases and decreases can be suppressed and the rate of temperature increases and decreases can be increased while the creation of particles is also suppressed.
As a result, particularly in the steps of manufacturing a semiconductor apparatus or a flat panel display apparatus, after temperature conditions have been changed so that the temperature increases or decreases, the heating process can be quickly carried out under different conditions. By achieving highly uniform heat properties in the placement surface of the placement stand, it is possible to reduce discrepancies in the film thickness or line width during, for example, the photolithography step of the semiconductor manufacturing process. Furthermore, in the inspection step, it is possible to consistently replicate fixed uniform heat properties and probing properties in the prober apparatus without varying the flatness of the placement surface.
It is thereby possible to provide a heating and cooling device which is highly reliably for a manufacturing apparatus or inspection apparatus of a semiconductor substrate or a glass substrate for a flat panel display. That is, by stabilizing the temperature discrepancies in the placement surface in the heat treatment step and shortening the time needed to change the temperature for temperature increases and cooling, it is possible to improve the productivity, performance, yield rate, and reliability of semiconductor apparatuses and flat panel display apparatuses manufactured and inspected by this heat treatment step. In the present invention, manufacturing at low cost can also be achieved.
The heater unit of the present invention is a heater unit comprising a first uniform heat plate having a placement surface on which a substrate is placed, a second uniform heat plate for supporting the first uniform heat plate, and an insulated resistance heating element made of at least one layer provided between the first uniform heat plate and the second uniform heat plate, wherein the first uniform heat plate and the second uniform heat plate have different thermal conductivities and Young's moduli.
The heating and cooling device of the present invention comprises the heater unit of the present invention, and a mobile cooling plate provided underneath the heater unit.
The manufacturing or inspection device for a semiconductor substrate or for a glass substrate for a flat panel display of the present invention comprises the heater unit or the heating and cooling device of the present invention. Preferred embodiments of the present invention are described hereinbelow with reference to the drawings.
First, the first embodiment of the present invention will be described.
The heater unit of the first embodiment of the present invention is the heater unit characterized in that the first uniform heat plate is composed of metal, the second uniform heat plate is composed of a ceramic or a metal-ceramic composite material, the relationship between the thermal conductivities of the first uniform heat plate and the second uniform heat plate, denoted as K1 and K2 respectively, is K1>K2, and the relationship between the Young's moduli of the first uniform heat plate and the second uniform heat plate, denoted as Y1 and Y2 respectively, is Y2>Y1.
The first uniform heat plate 11 is formed from a metal that is a material having high thermal conductivity in order to obtain highly uniform heat properties in the wafer placement surface 11a. The type of metal is not particularly limited, but the thermal conductivity is preferably 100 W/mK or greater. Possible examples of this metal include copper, aluminum, tungsten, molybdenum, alloys including these metals, and the like.
The second uniform heat plate 12 is formed from a ceramic or a metal-ceramic composite material that has a high Young's modulus in order to provide the entire heater unit 10 with high rigidity. The type of ceramic is not particularly limited, but possible examples include silicon carbide, alumina, aluminum nitride, silicon nitride, and the like. Possible examples of the metal-ceramic composite material include a composite of aluminum or silicon, and silicon carbide, aluminum nitride, or another ceramic.
When the uniform heat plate is made of metal or a metal-ceramic composite material, the surface may be treated with a highly corrosion-resistant material such as Ni or another comparatively hard metal, alumite, or another ceramic, or a Teflon-based or polyimide-based resin. In addition to durability being improved by such a surface treatment, it is possible to prevent contamination or the occurrence of particles which would be a source of contamination in the semiconductor manufacturing apparatus or other final products. The same surface treatment may of course also be performed in the case of ceramics.
In the first embodiment of the present invention, with the combination of materials of the first uniform heat plate 11 and the second uniform heat plate 12 as described above, when the thermal conductivity of the first uniform heat plate 11 at room temperature is denoted as K1, the Young's modulus as Y1, the thermal conductivity of the second uniform heat plate 12 as K2, and the Young's modulus as Y2, they have the relationships K1>K2 and Y2>Y1. Thereby, the first uniform heat plate 11 can be given the role of increasing the uniform heat properties in the wafer placement surface 11a, while the second uniform heat plate 12 can be given the role of increasing the rigidity of the entire heater unit 10, and as a result, it is possible to achieve with low cost a heater unit 10 having both highly uniform heat properties and high rigidity.
That is, the first uniform heat plate 11 is formed from a metal of high thermal conductivity and the second uniform heat plate 12 is formed from a highly rigid ceramic or metal-ceramic composite material so as to satisfy the aforementioned relationships between the two layer's thermal conductivities and between the two layer's Young's moduli, and the insulated resistance heating element 13 also provided between these two plates, whereby the heat generated by the insulated resistance heating element 13 can be transferred to the first uniform heat plate 11 of high thermal conductivity and quickly diffused through the entire surface of the wafer placement surface 11a. Highly uniform heat properties are thereby obtained in the wafer placement surface 11a.
Since the rigidity of the heater unit 10 can be settled by the second uniform heat plate 12, the first uniform heat plate 11 can be reduced in thickness. As a result, the heat capacity of the first uniform heat plate 11 can be reduced, and it is possible to rapidly increase or reduce the temperature of the wafer placed on the wafer placement surface 11a. Thus, rapid temperature increase is possible regardless of the heater unit 10 shown in FIG. 1 being highly rigid. This is particularly effective when the heater unit 10 is used in an inspection apparatus such as a wafer prober which applies a strong perpendicular force to the wafer placement surface 11a.
The specific Young's modulus of the second uniform heat plate 12 is not particularly limited, but is preferably 200 GPa or greater. This is because at 200 GPa or greater, the deformation of the second uniform heat plate 12 can be reduced significantly, and the second uniform heat plate 12 can thereby be made thinner and lighter.
As described above, the second uniform heat plate 12 is characterized in having high rigidity and a lower thermal conductivity than the first uniform heat plate 11, but the thermal conductivity of the second uniform heat plate 12 is preferably high to a certain extent. The reason for this is because the mobile cooling plate is provided at the bottom of the second uniform heat plate 12 as will be described hereinafter, and the heat of the heater unit 10 can therefore be transferred to the cooling plate without requiring much time. From this viewpoint, the material of the second uniform heat plate 12 is preferably silicon carbide, aluminum nitride, or silicon nitride in the case of a ceramic, and preferably a composite of aluminum or silicon and silicon carbide or aluminum nitride in the case of a metal-ceramic composite material.
The second uniform heat plate 12 and the first uniform heat plate 11 which has the lower Young's modulus are bonded together by screws or the like as will be described hereinafter, and the first uniform heat plate 11 and the second uniform heat plate 12 are thereby firmly fixed together via the insulated resistance heating element 13. When heating and cooling are alternately repeated by the insulated resistance heating element 13 and the hereinafter-described mobile cooling plate 20 in this state, the surface of the first uniform heat plate 11 in contact with the insulated resistance heating element 13 conforms to the shape of the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13, regardless of the insulated resistance heating element 13 being located in between the two plates. In other words, the surface of the former deforms along the shape of the surface of the latter.
As a result, if the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 has poor flatness, the flatness of the surface of the first uniform heat plate 11 in contact with the insulated resistance heating element 13 is also worsened, and the effect of this causes the flatness of the wafer placement surface 11a of the first uniform heat plate 11 to worsen. Thereby, there is a risk of the uniform heat properties being reduced in the wafer placement surface 11a. To avoid such problems, the flatness of the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 is preferably 100 μm or less, and more preferably 50 μm or less. Specifically, if the flatness exceeds 100 μm, the flatness of the wafer placement surface 11a gradually worsens, and there is a risk that the uniform heat properties in the wafer placement surface 11a will decrease as well.
Even if the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 has a flatness of 100 μm or less, the shape of this surface, rather than being upwardly convex, preferably concaves upward, i.e., preferably has a mortar-like shape wherein the substantial center of the surface is caved in. The reason for this is because if the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 concaves upward, the deformation of the first uniform heat plate II along this shape progresses smoothly, and the effect of the decrease in uniform heat properties in the wafer placement surface 11a can therefore be reduced. The term “flatness of the surface” refers to the distance between two other flat surfaces parallel to each other on either sides of the first surface, wherein the two flat surfaces are envisioned as having the shortest possible distance separating them from each other.
The first uniform heat plate 11 may have a hole, groove, or other concavity for fixing the placed wafer by suction in the side with the wafer placement surface 11a. This concavity is formed by common mechanical processing, and the first uniform heat plate 11 is therefore preferably a material that is easily mechanically processed. This is another respect from which it is preferable that the first uniform heat plate 11 be a material having a lower Young's modulus than the second uniform heat plate 12.
A possible example of a preferred embodiment of the heater unit 10 which takes all this into account is a case in which copper or a copper alloy is used for the material of the first uniform heat plate 11, and SiC, AlN, Si—SiC (a composite of Si and Sic), or Al—SiC (a composite of Al and SiC) is used for the material of the second uniform heat plate 12. When the intention is to make the heater unit 10 lighter, aluminum or an alloy thereof is preferably used for the material of the first uniform heat plate 11, and SiC or Si—SiC is preferably used for the material of the second uniform heat plate 12.
In the first embodiment of the present invention, the total (A1+A2) of the thickness of the first uniform heat plate 11 (A1) and the thickness of the second uniform heat plate 12 (A2) is preferably 1/40 of the diameter of the first uniform heat plate 11 (B) or less. If this value exceeds 1/40, the heat capacity of the entire heater unit 10 will be too large, and it will be difficult to rapidly increase the temperature or perform rapid cooling. The thickness of the first uniform heat plate 11 (A1) and the thickness of the second uniform heat plate 12 (A2) are both preferably 1 mm or greater. This is because if these thicknesses are any lower, there is a risk of the first uniform heat plate 11 or the second uniform heat plate 12 warping or cracking.
The resistance heating element 13a heats the wafer placed on the wafer placement surface 11a by Joule heat produced when electricity is supplied to a conductor. This conductor is not limited, but microfabricated metal foil is preferably used. Examples of materials that can be used for the conductor include nickel, stainless steel, silver, tungsten, molybdenum, chrome, inconel, and alloys thereof. For example, a stainless steel or nickel chrome foil can be formed by etching so as to form a spiraling heating element circuit pattern, for example. Of these examples, stainless steel in particular is preferred. This is because a fine metal foil can be processed in a comparatively precise manner. In addition to being inexpensive, this foil is also preferred because, being resistant to oxidation, the foil can withstand use over extended periods even at high temperatures. Possible examples of the method for processing the fine metal foil include etching, laser processing, and the like.
The insulated resistance heating element 13 of the present invention may have a structure in which a heat-resistant insulator is integrally formed with a resistance heating element 13a. The heat-resistant insulator may be a heat-resistant insulator whose primary constituent is polyimide or Teflon, or both. The thickness (C) of the insulated resistance heating element 13 having this integrated structure is preferably 0.5 mm or less. This is because if the thickness exceeds 0.5 mm, there will be heat transfer resistance during cooling, and it will be difficult to perform rapid cooling. The lower limit of the thickness (C) of the insulated resistance heating element 13 having this integrated structure is not particularly limited, but is commonly 0.02 mm or greater. This is because it is technically difficult to create a thin insulated resistance heating element 13 having a thickness of less than 0.02 mm, and it would not be cost-effective.
Insulation can be provided between the resistance heating element 13a and the first uniform heat plate 11, between the resistance heating element 13a and the second uniform heat plate 12, or between two resistance heating elements 13a, for example, by providing a sheet having electrical insulating properties. When there are a plural number of layers of resistance heating elements 13a, their stacking order is not particularly limited, but the rate of temperature increase can be changed from that of the case of one layer by stacking a plurality of layers and allowing them to be energized individually. It is also possible to create a design which further improves uniform heat properties because local temperature control can be performed, for example, by combining heating element circuits having different patterns.
Flexible insulating sheets may be used between the first and second uniform heat plates 11, 12 and the resistance heating element 13a in order to satisfactorily diffuse the heat of the resistance heating element 13a. In this case, it is preferable that a sheet having as high of a thermal conductivity as possible be used for the insulating sheet.
For example, when two resistance heating elements 13a are provided, the configuration is preferably as is shown in
In cases of a plurality of resistance heating elements 13a, the resistance heating elements 13a can be adhered or fused together via an insulating sheet 13b, the insulating sheets 13b adjacent to the first and second uniform heat plates 11, 12 can also be adhered or fused to the resistance heating elements 13a, and the resistance heating elements 13a and insulating sheets 13b can have an integrated structure. When a plurality of resistance heating elements 13a are integrated in an insulated state in this manner, setting the resistance heating elements 13a between the first and second uniform heat plates 11, 12 becomes easier. The insulated resistance heating element may be adhered or fused individually to the first uniform heat plate 11 and/or the second uniform heat plate 12. Setting becomes easier in this case as well. It is preferable that the thinner the insulating sheet 13b, the more the heat resistance can be reduced, as long as the thickness required in the electrical insulating design of the resistance heating element 13a is satisfied.
The heater unit 10 is obtained by sandwiching and bonding this insulated resistance heating element 13 between the first uniform heat plate 11 and the second uniform heat plate 12. For this bonding, the first uniform heat plate 11 and the second uniform heat plate 12 are preferably fixed together using screws, clamps, or another mechanical bonding means, for example. The first uniform heat plate 11 and the insulated resistance heating element 13 can be adhered together, as can the second uniform heat plate 12 and the insulated resistance heating element 13, by an adhesive or another adhesion means. Furthermore, a groove, hole, or other concavity for vacuum-suction may be mechanically processed into the surface of the first uniform heat plate 11 on the side opposite the wafer placement surface 11a, and the first uniform heat plate 11 and the insulated resistance heating element 13 may be vacuum-suctioned together. The adhesion between the first uniform heat plate 11 and the second uniform heat plate 12 via the insulated resistance heating element 13 is further improved by combining these bonding means, and the heat transfer rate can therefore be further improved.
Although it is more difficult to mechanically process than the first uniform heat plate 11, the surface of the second uniform heat plate 12 facing the insulated resistance heating element 13 may be provided with a groove, hole, or other concavity for vacuum-suction, and the second uniform heat plate 12 and the insulated resistance heating element 13 may be vacuum-suctioned together. A plurality of integrated insulated resistance heating elements 13 may be stacked and sandwiched between the first uniform heat plate 11 and the second uniform heat plate 12. Thereby, the rate of temperature increase can be increased, and resistance heating elements having different metal foil patterns can be stacked to make more precise temperature control possible.
The wafer placement surface 11a of the first uniform heat plate 11 preferably has a surface roughness Ra of 0.5 μm or less. This is because if this value exceeds 0.5 μm, it will be difficult, during the probing of a semiconductor element which generates a large amount of heat, for the heat generated by the semiconductor element itself to be satisfactorily transferred to the first uniform heat plate 11, and there is a risk that the temperature of the semiconductor element will be too high, causing thermal fracture. It is more preferable that the surface roughness Ra be 0.02 μm or less because heat can be radiated more efficiently.
After the heater unit 10 has been assembled by bonding the first uniform heat plate 11 and the second uniform heat plate 12 together via the insulated resistance heating element 13, the entire heater unit 10 may be heat treated so as to have a heat history in a temperature range (e.g., room temperature to 300° C.) encompassing the temperature range in which the heater unit is actually used. This heat treatment of the heater unit 10 can be performed in a simple manner by causing the insulated resistance heating element 13 provided to the heater unit 10 to generate heat.
Thus, by adding a heat history to the heater unit 10 in advance, the metal uniform heat plate can be made to almost perfectly conform to the other uniform heat plate made of a ceramic or a metal-ceramic composite material, and the when the heater unit is subsequently actually used, the flatness in the placement surface 11a of the first uniform heat plate 11 remains substantially unchanged. Consequently, a heater unit 10 of extremely high reliability can be created.
It is preferable that the heater unit 10 be provided with a temperature sensor 40 as shown in
There are also cases in which the heater unit 10 is provided with a bypass hole for allowing the cable of the temperature sensor to pass through, a through-hole for a lifter pin for lifting up the substrate, a hole for allowing the passage of a cable for energizing the resistance heating element 13, and the like. In such cases, airtightness can be ensured by providing O-rings or other vacuum-sealing members so as to encircle these holes.
The mobile cooling plate 20 is provided at the bottom of the heater unit 10. This mobile cooling plate 20 separates from the heater unit 10 as shown in
When the heater unit 10 is used in an inspection apparatus such as a wafer prober, the mobile cooling plate 20 is separated from the heater unit 10 during probing, whereby the pressure of the probe card can be entirely prevented from reaching the mobile cooling plate 20. Consequently, the mobile cooling plate 20 can have a simple and lightweight structure. An air cylinder or another raising/lowering means can be used as the method for driving the mobile cooling plate 20.
A soft member (not shown) having deforming capability, heat resistance, and a high thermal conductivity may be provided between the heater unit 10 and the mobile cooling plate 20. It is thereby possible to alleviate the problem with flatness or warpage in the opposing surfaces of the heater unit 10 and mobile cooling plate 20 as well as the resulting problem with heat transfer resistance. As a result, the original cooling capacity of the mobile cooling plate 20 can be achieved at its maximum limit, and the heater unit 10 can therefore be cooled more rapidly.
Possible examples that can be used for the material of this soft member include a silicon resin; epoxy, phenol, polyimide, or another heat-resistant resin; or BN, silica, AlN, or another filler dispersed in these resins in order to improve thermal conductivity. Alternatively, a foamed metal may be used.
The material of the mobile cooling plate 20 is not particularly restricted, and aluminum, copper, or an alloy thereof is preferred. This is because these metals have comparatively high thermal conductivity and can therefore absorb the heat of the heater unit 10 rapidly. Stainless steel, a magnesium alloy, nickel, or another metal material may also be used. Furthermore, in order to provide oxidation resistance to the mobile cooling plate 20, a metal film having oxidation resistance, such as nickel, gold, or silver may be formed using plating, spraying, or another method.
A ceramic may also be used as the material of the mobile cooling plate 20. In this case, the material is not particularly limited, but aluminum nitride or silicon carbide is preferred. This is because these materials have comparatively high thermal conductivities and can therefore quickly absorb the heat of the heater unit 10. Alternatively, silicon nitride or aluminum oxynitride may be used. This is because these materials have high mechanical strength and excellent durability. Furthermore, comparatively inexpensive alumina, cordelite, steatite, and other oxide ceramics may be used.
Since the material of the mobile cooling plate 20 can be selected from various options as described above, the material can be selected according to its application. Of these examples, aluminum treated with alumite and copper plated with nickel are preferred for the excellent oxidation resistance, high thermal conductivity, and comparatively low price.
A refrigerant can also be flowed to the mobile cooling plate 20. For example, referring to
Since the heat transmitted from the heater unit 10 can thereby be quickly expelled out of the system, the system can be cooled more rapidly. The type of refrigerant is not limited, but water, Fluorinert, or another refrigerant is preferred, and water is more preferred when taking its high specific heat or price into account.
The mobile cooling plate 20 of
A mobile cooling plate 20 having a structure through which refrigerant flows is formed by preparing two copper (oxygen-free copper) plates, for example, and mechanically processing a flow passage through which water flows in one of the copper plates. In this copper plate, the other copper plate and a stainless steel pipe for letting refrigerant in and out are bonded together by soldering. To improve the corrosion resistance and oxidation resistance of the two bonded copper plates, the copper plates can be prepared by forming nickel plating over their entire surfaces.
Alternatively, as another structure for allowing the flow of refrigerant, a pipe allowing the flow of refrigerant may be installed in an aluminum plate, a copper plate, or another cooling plate. In this case, the cooling efficiency can be further improved by forming a counterbore groove having a shape similar to the cross-sectional shape of the pipe in the cooling plate and firmly adhering the pipe into the groove. To improve adhesion, a resin, ceramic, or another material having high thermal conductivity may be provided between the pipe and the cooling plate.
The heater unit 10 and the mobile cooling plate 20 are preferably accommodated in a container 30 composed of stainless steel or the like for shielding the heat of the heater unit 10 from easily transferring to other production apparatuses (
In the first embodiment of the present invention, a support member (not shown) is preferably provided in order to ensure that the heat produced in the heater unit 10 is not transferred to components located below the heating and cooling device 1. The shape of this support member is not particularly restricted, but the support member is preferably not in direct contact with the insulated resistance heating element 13. For example, a structure is preferred in which the bottom surface of the second uniform heat plate 12 is directly supported by a plurality of support columns arranged in a radial pattern. In this case, depending on the shape of the mobile cooling plate 20, a through-hole or a recess must be formed in the cooling plate 20 so that the cooling plate 20 does not physically interfere with the support member. The shape and number of support members are not particularly limited.
The thermal conductivity of the support member is preferably lower than the thermal conductivity of the second uniform heat plate 12, i.e., the value of K2 previously described. This impedes the heat of the heater unit 10 from being transferred to the components located below the support member, and it is therefore possible to prevent heat from being transferred to the components of the drive system used in the positional alignment of the wafer which is a component located at the bottom, for example. As a result, thermal expansion of the components of this drive system can be prevented, and reductions in the positional alignment precision of the wafer or the like can be prevented.
The heating and cooling device 1 having the heater unit 10 and the mobile cooling plate 20 is preferably accommodated in the container 30 as shown in
The heating and cooling device comprising the heater unit of the first embodiment of the present invention is capable of rapid temperature increases and rapid cooling and has high rigidity in addition to having highly uniform heat properties in the wafer placement surface, and it is therefore possible to manufacture high-quality semiconductor elements with high throughput by installing the heating and cooling device in a semiconductor manufacturing apparatus or a semiconductor element inspection apparatus.
The second embodiment of the present invention is described hereinbelow.
In the heater unit of the second embodiment of the present invention, the first uniform heat plate and the second uniform heat plate are bonded together so as to be capable of moving relative to each other in substantially parallel directions in relation to their mutually opposing surfaces, and between the first uniform heat plate and the second uniform heat plate, one is composed of a metal and subjected to processing intended to provide flexibility to at least one side, while the other is composed of a ceramic or a metal-ceramic composite material.
The material used in the uniform heat plate on which the substrate is placed is preferably a material having high thermal conductivity. The reason for this is because the higher the thermal conductivity, the higher uniform heat properties can be maintained even if the uniform heat plate is thinned, and the heat capacity of the uniform heat plate can therefore be kept small to increase the rate of temperature increase. In view of this, the uniform heat plate is preferably formed from only a metal having high thermal conductivity, but since metals have low Young's moduli, they warp readily when formed thin, they warp readily depending on heat history such as temperature raising and lowering, and it has not been possible to thin the uniform heat plate.
Because of this, in the second embodiment of the present invention, the first uniform heat plate 11 and the second uniform heat plate 12 as used as uniform heat plates, wherein one is formed from a metal material while the other is formed from a ceramic or a metal-ceramic composite material. It is thereby possible for these materials to exhibit their special functions, and excellent uniform heat plates can therefore be obtained which have the advantages of both materials. In other words, in the first embodiment previously described, the materials of the first uniform heat plate 11 and the second uniform heat plate 12 were a metal and a ceramic or a metal-ceramic composite material, respectively, whereas in Embodiment 2, the materials may be the above combination used in the first embodiment as well as may be a ceramic or a metal-ceramic composite material for the first uniform heat plate 11 and a metal for the second uniform heat plate 12.
Since the metal is characterized by its high thermal conductivity in particular, the function of uniform heat properties obtained thereby can be exhibited in one of the uniform heat plates. Since the ceramic or metal-ceramic composite material is characterized by its high rigidity and low thermal expansion, the function of maintaining flatness during temperature increasing and decreasing obtained thereby can be exhibited in the other uniform heat plate. These two uniform heat plates are bonded together via the insulated resistance heating element, whereby it is possible to simultaneously achieve the various characteristics that cannot be achieved with one uniform heat plate alone, i.e., highly uniform heat properties, a high degree of flatness which does not readily change even during temperature increases and decreases, and fast temperature increasing and decreasing properties due to thinning.
For example, the first uniform heat plate 11 which has the placement surface 11a may be formed from a metal, and the second uniform heat plate 12 may be formed from a ceramic or a metal-ceramic composite material, as shown in
Forming the first uniform heat plate 11 having the placement surface 11a from a metal has an advantage in that it is easy to perform processes on the first uniform heat plate 11 itself, such as vacuous groove processing for suctioning the substrate usually formed on the placement surface 11a, for example. Forming the first uniform heat plate 11 from a ceramic or a metal-ceramic composite material has an advantage in that the first uniform heat plate 11 has high rigidity, therefore there is little deformation from processing and high-precision processing is easier.
In either case, the first uniform heat plate 11 and the second uniform heat plate 12 are preferably formed from materials having high thermal conductivities. The reason for this is because, as previously described, the higher the thermal conductivity, the thinner the uniform heat plate can be made. Particularly, the uniform heat plates preferably have thermal conductivities of 150 W/mK or greater. It is more preferably 200 W/mK or greater when the uniform heat plate is made of metal. Possible examples of metals that satisfy this condition include Cu, Al, and alloys containing these metals.
A uniform heat plate made from a ceramic or a metal-ceramic composite material preferably has a Young's modulus of 200 GPa or greater. This is because the higher the Young's modulus, the more the uniform heat plate can be thinned. Possible examples of the ceramic include AlN, SiC, alumina, silicon nitride, and composites of these ceramics. Possible examples of the metal-ceramic composite material include composites of Si, Al, or another metal, and silicon carbide, MN, or another ceramic. It is preferable to use a composite of Si and silicon carbide, a composite of Al and silicon carbide, a composite of Si, Al, and silicon carbide, or a composite containing these composites. This is because these materials have high thermal conductivities and high Young's moduli.
When the uniform heat plates are made of metal or a metal-ceramic composite material, they may be surface treated with Ni or another comparatively hard metal, alumite or another ceramic, or a Teflon-based or polyimide-based resin or another highly corrosion-resistant material. In addition to improving durability, such a surface treatment can prevent the occurrence of contaminants or particles that would be sources of contamination in the semiconductor apparatus or other final product. The same surface treatment may of course also be performed in the case of a ceramic.
Next, the flexibility provided to the uniform heat plates in the second embodiment is described.
The uniform heat plate made of metal is subjected to processing for providing flexibility to at least one side. The uniform heat plate made of metal thereby readily conforms to the other highly rigid uniform heat plate which is made of a ceramic or a metal-ceramic composite material. That is, even if the metal uniform heat plate undergoes a severe change in temperature, this metal uniform heat plate can elastically deform so as to constantly conform to the opposing surface of the other opposing uniform heat plate. It is apparent that this results in particularly preferable effects for a heater unit for heating substrate such as the one described hereinbelow.
That is, by subjecting the metal uniform heat plate to processing for providing flexibility and enabling this uniform heat plate to readily conform to the other highly rigid uniform heat plate, warping can be suppressed even if the metal uniform heat plate is thinned, flatness does not worsen during temperature increasing and decreasing, and the uniform heat properties consequently do not worsen. Since the metal has high thermal conductivity, the uniform heat properties are not compromised even if the metal is low in thickness. Consequently, since the metal can be reduced in thickness, the heat capacity is low, and fast temperature increasing and decreasing is possible.
The processing for providing flexibility to the metal uniform heat plate can involve forming concavities N in such forms as notches, recesses, hollows, scratches, incisions, bottomed holes, and through-holes, as shown in
Nor are there any particular limits on the number (density) of concavities N per unit surface area of the placement surface, the density distribution, the spaces between adjacent concavities, or other factors, which are preferably optimized to an extent which yields the flexibility needed in order to make the uniform heat plate readily conform to the other uniform heat plate. Among these processing examples, recesses in particular are preferred. The reason for this is because sufficient flexibility can be provided by processing a small number of recesses, and the processing can also be performed inexpensively. The processing of such recesses can be performed by mechanical cutting, for example.
The concavities N for providing flexibility may be provided to one side alone of the metal uniform heat plate as in
Furthermore, if the metal uniform heat plate provided with concavities N on both sides is the first uniform heat plate 11, concavities N for providing flexibility in the side with the placement surface 11a can also be used as grooves for suctioning the substrate as previously described.
Furthermore, the metal uniform heat plate is preferably appropriately heat treated at a temperature equal to or greater than the temperature needed to anneal the metal. For example, when Cu is used for the metal uniform heat plate, the temperature needed to anneal Cu is approximately 380° C., and a heat treatment is therefore preferably performed for keeping the Cu uniform heat plate at 400 to 450° C. for 15 minutes to 8 hours. The metal uniform heat plate thereby conforms to the other uniform heat plate made of a ceramic or a metal-ceramic composite material even more readily.
The thickness of the metal uniform heat plate in the second embodiment is preferably equal to or less than the thickness of the uniform heat plate made of a ceramic or a metal-ceramic composite material. This is because thinning the metal uniform heat plate as much as possible makes this uniform heat plate conform more readily to the plate surface of the uniform heat plate made of a rigid ceramic or a metal-ceramic composite material. The uniform heat plate made of a ceramic or a metal-ceramic composite material is preferably thick enough to ensure rigidity.
Due to the thickness of the metal uniform heat plate being equal to or less than the thickness of the uniform heat plate made of a ceramic or a metal-ceramic composite material, the metal uniform heat plate conforms more readily to the plate surface of the uniform heat plate made of a rigid ceramic or a metal-ceramic composite material. Consequently, the highly uniform heat properties and the excellent flatness can be maintained, the total thickness of the heater unit can be reduced, the total heat capacity can be suppressed, and the temperature can therefore be increased and decreased quickly.
The insulated resistance heating element 13, the resistance heating element 13a, the insulating sheet 13b, the temperature sensor 40, the support member, the container (30), the bypass hole for allowing passage of the cable of the temperature sensor provided to the heater unit 10, the through-hole for the lifter pin for lifting up the substrate, and hole for allowing passage of the cable for energizing the insulated resistance heating element 13, the soft member, and other components can be the same as those described in the first embodiment.
In the second embodiment of the present invention, the first uniform heat plate 11 and the second uniform heat plate 12 facing each other via the insulated resistance heating element 13 are bonded together so as to be capable of moving relative to each other in substantially parallel directions in relation to their opposing surfaces, whereby the one uniform heat plate made of metal can conform to the other uniform heat plate made of a ceramic or a metal-ceramic composite material even when the temperature changes. Possible examples of the method for bonding these uniform heat plates together in a manner that allows them to move relative to each other in substantially parallel directions relative to their opposing surfaces include a method of bonding using vacuum-suction means, and bonding method that uses bonding means combining screws and bearings.
To specifically describe the method of bonding using vacuum-suction means, a groove or another concavity is formed in the surface of the first uniform heat plate 11 facing the insulated resistance heating element 13, and furthermore, through-holes running into the space formed by this concavity are formed in the insulated resistance heating element 13 and the second uniform heat plate 12. The insulated resistance heating element 13 and the first uniform heat plate 11 can be vacuum-suctioned together by vacuuming this space via the through-holes by a vacuum pump or other vacuum-creating means. The vacuum suction between the second uniform heat plate 12 and the insulated resistance heating element 13 can also be accomplished by vacuuming via the groove or other concavity and through-hole formed in the second uniform heat plate 12.
To specifically describe the bonding method that uses bonding means combining screws and bearings, a screw hole 11b is formed in the surface of the first uniform heat plate 11 that faces the insulated resistance heating element 13 as shown in
Bearing grooves 14a are provided in the bearing surface of the head of the screw 14, and bearing balls 15 are held in these bearing grooves 14a. The head of the screw 14 is thereby able to move in the direction of the surface of the second uniform heat plate 12 that is parallel to the bearing surface. The bearing structure is not limited to this structure; bearing grooves 12a may be provided in locations in the second uniform heat plate 12 that face the bearing surface of the head of the screw 14, while the bearing balls 15 are held in these bearing grooves 12a as shown in
In the vacuum suction method or the method of bonding using a method combining screws and bearings such as those described above, the first uniform heat plate 11 and the insulated resistance heating element 13 can be made to slide against each other in their bordering surfaces. The second uniform heat plate 12 and the insulated resistance heating element 13 can also be made to slide against each other in their bordering surfaces. In the case of two or more insulated resistance heating elements 13, the heat elements insulating each other can be made to slide in their bordering surfaces. As a result, the difference in thermal expansion between the first uniform heat plate 11 and the second uniform heat plate 12 can be absorbed. Warping due to the difference in thermal expansion between these components during temperature increasing or decreasing is thus suppressed, whereby satisfactory uniform heat properties in the placement surface can be ensured.
In the second embodiment of the present invention as previously described, since the metal uniform heat plate is subjected to processing for providing flexibility, the metal uniform heat plate more readily conforms to the uniform heat plate made of a ceramic or a metal-ceramic composite material. Consequently, warping caused by the difference in thermal expansion between the first uniform heat plate 11 and the second uniform heat plate 12 can be reliably suppressed, and satisfactory uniform heat properties in the placement surface can be ensured.
After the heater unit 10 has been assembled by bonding the first uniform heat plate 11 and the second uniform heat plate 12 together via the insulated resistance heating element 13, the entire heater unit 10 may be heat treated so as to have a heat history in a temperature range (e.g., room temperature to 300° C.) encompassing the temperature range in which the heater unit is actually used. This heat treatment of the heater unit 10 can be performed in a simple manner by causing the insulated resistance heating element 13 provided to the heater unit 10 to generate heat.
Thus, by adding a heat history to the heater unit 10 in advance, the metal uniform heat plate can be made to almost perfectly conform to the other uniform heat plate made of a ceramic or a metal-ceramic composite material, and the when the heater unit is subsequently actually used, the flatness in the placement surface 11a of the first uniform heat plate 11 remains substantially unchanged. Consequently, a heater unit 10 of extremely high reliability can be created.
Thus, in the heater unit 10 of the second embodiment of the present invention described above, one of the two uniform heat plates is made of metal subjected to processing for providing flexibility and this metal plate is also subjected to annealing as necessary, while the other uniform heat plate is made of a ceramic or a metal-ceramic composite material. In addition to these two uniform heat plates being made to face each other via the insulated resistance heating element 13, the heater unit is also characterized in that the two uniform heat plates are bonded together so as to be capable of moving relative to each other in substantially parallel directions relative to their opposing surfaces.
It is thereby possible to provide a heater unit having uniform heat properties, stability of flatness, and fast increases and decreases in temperature, which were not attainable in conventional heater units composed of metal plates alone or heater units composed of ceramics or metal-ceramic composite materials alone.
After these two uniform heat plates are bonded together via the insulated resistance heating element, it is also possible to further improve the uniform heat properties and the stability of flatness by heat treating the entire integrated heater unit as necessary.
That is, in cases in conventional practice in which heat resistance is reduced between the placement stand for placing a semiconductor wafer or another substrate and the cooling plate for cooling this placement stand, for example, methods for securely fixing these two components together across nearly their entire opposing surfaces have been used, these methods using either an adhesive or screws or other bonding means. However, with these methods, there have been instances of bimetal-derived warping during increases and decreases in temperature, as a result of the difference in thermal expansion between the placement stand and the cooling plate. As a result, there have been instances in which the flatness maintained at room temperature worsens and the uniform heat properties of the substrate placed on the placement surface worsen severely.
As a countermeasure to this, in the heater unit of the second embodiment of the present invention, performing a process or treatment which makes one uniform heat plate conform readily to the other uniform heat plate as previously described makes it possible to continually keep the flatness of the placement surface substantially constant, not only at room temperature but during temperature increases and decreases as well. The bonding of the two uniform heat plates via the insulated resistance heating element is not limited to the above-described vacuum suction, the method combining screws and bearings, or adhesion or fusion using the flexible insulating sheet described above. Any desired bonding means can be used if the bonding allows the one uniform heat plate to deform so as to conform to the other uniform heat plate when the temperature of the heater unit is increased or decreased.
When heating and cooling are alternately repeated by the insulated resistance heating element 13 and the mobile cooling plate 20 described hereinafter in a state in which the first uniform heat plate 11 and the second uniform heat plate 12 are bonded together via the insulated resistance heating element 13, the surface of the first uniform heat plate 11 in contact with the insulated resistance heating element 13 conforms to the shape of the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 regardless of the insulated resistance heating element 13 being located between the two sheets, as previously described. In other words, the surface of the former deforms along the surface of the latter.
As a result, if the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 has poor flatness, the flatness of the surface of the first uniform heat plate 11 in contact with the insulated resistance heating element 13 is also worsened, and the effect of this causes the flatness of the placement surface 11a of the first uniform heat plate 11 to worsen. Thereby, there is a risk of the uniform heat properties being reduced in the placement surface 11a. To avoid such problems, the flatness of the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 is preferably 100 μm or less, and more preferably 50 μm or less. Specifically, if the flatness exceeds 100 μm, the flatness of the placement surface 11a gradually worsens, and there is a risk that the uniform heat properties in the placement surface 11a will decrease as well.
Even if the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 has a flatness of 100 μm or less, the shape of this surface, rather than being upwardly convex, preferably concaves upward, i.e., preferably has a mortar-like shape wherein the substantial center of the surface is caved in. The reason for this is because if the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 concaves upward, the deformation of the first uniform heat plate 11 along this shape progresses smoothly, and the effect of the decrease in uniform heat properties in the placement surface 11a can therefore be reduced. The term “flatness of the surface” refers to the distance between two other flat surfaces parallel to each other on either sides of the first surface, wherein the two flat surfaces are envisioned as having the shortest possible distance separating them from each other.
In the heater unit 10 of the second embodiment of the present invention, when the first uniform heat plate 11 and the second uniform heat plate 12 are bonded together by vacuum suction as previously described, a vacuum-sealing member is preferably included in order to strengthen the vacuum suction. This vacuum-sealing member is preferred because the adherence can be improved by providing the vacuum-sealing member around the external peripheries of both the first uniform heat plate 11 and the second uniform heat plate 12.
For example, a possible specific example of a structure comprising a vacuum-sealing member is a structure in which a vacuum-sealing member is formed by an annular elastic member 16a, and this elastic member 16a is provided in a portion facing flanges provided in the external peripheries of both the first and second uniform heat plates 11, 12, as shown in
Alternatively, an annular elastic member 16b may be provided around the external peripheral surfaces of the first uniform heat plate 11 and the second uniform heat plate 12 so as to encircle the external edges of the opposing sides of the first uniform heat plate 11 and the second uniform heat plate 12, as shown in
As yet another specific example, the external peripheries of the opposing surfaces of the first uniform heat plate 11 and the second uniform heat plate 12 can have grooves processed therein which face each other across the entire peripheries as shown in
As in the first embodiment, a heating and cooling device can be created by providing a cooling plate as necessary underneath the heater unit 10 of the second embodiment. The cooling plate can be the same mobile cooling plate described in the first embodiment.
As described above, in the heater unit of the second embodiment, which has a structure in which a metal uniform heat plate and a uniform heat plate made of a ceramic or a metal-ceramic composite material are bonded together via an insulated resistance heating element so as to be capable of moving relative to each other in directions substantially parallel to their opposing surfaces, the metal uniform heat plate is subjected to processing for providing flexibility, and a heat treatment is performed as necessary on the metal uniform heat plate prior to bonding or on the heater unit after it has been integrated. As a result, the metal uniform heat plate readily conforms to the uniform heat plate made of a ceramic or a metal-ceramic composite material, and, consequently, a state of adherence can constantly be maintained between these two uniform heat plates across almost their entire opposing surfaces, even when the temperature is repeatedly increased and decreased by the resistance heating element or the cooling plate.
Thereby, compared with conventional examples in which methods for securely fixing two members of different materials together using an adhesive or the like with the intention of reducing heat resistance, heating and cooling can be performed quickly without increasing heat resistance, and it is possible to reduce the bimetal-induced warping resulting from the difference in thermal expansion between the top and bottom uniform heat plates, even in conditions of severe temperature changes during rapid heating or rapid cooling. As a result, highly uniform heat properties can be constantly maintained in the substrate placed on the placement surface.
The third embodiment of the present invention is achieved by combining the characteristics of the first embodiment and the second embodiment. For example, the third embodiment of the present invention uses the first uniform heat plate and the second uniform heat plate used in the first embodiment (i.e., the first uniform heat plate which has the placement surface for placing the substrate, and the second uniform heat plate which supports the first uniform heat plate, wherein the thermal conductivities of the first uniform heat plate and second uniform heat plate, denoted as K1 and K2 respectively have the relationship K1>K2, and the Young's moduli of the first uniform heat plate and second uniform heat plate, denoted as Y1 and Y2 respectively, have the relationship Y2>Y1), and the first uniform heat plate and second uniform heat plate are bonded together so as to be capable of moving relative to each other in directions substantially parallel to their opposing surfaces.
According to the third embodiment, one of either the first uniform heat plate and the second uniform heat plate may be made from metal and subjected to processing for providing flexibility to at least one side, while the other may be made from a ceramic or a metal-ceramic composite material.
According to the third embodiment, among the first uniform heat plate and the second uniform heat plate, the thickness of the one made of metal may be equal to or less than the thickness of the other made of a ceramic or a metal-ceramic composite material.
In the second uniform heat plate, the shape of the surface in contact with the insulated resistance heating element may be upwardly concave.
The bond allowing for relative movement may be a bond accomplished by vacuum-suction means or a bond accomplished by bonding means combining screws and bearings.
A vacuum-sealing member used for the vacuum-suction means may also be provided.
The vacuum-sealing member may be disposed in the vicinity of the external peripheries of the first uniform heat plate and the second uniform heat plate.
The insulated resistance heating element is formed by integrating a resistance heating element and a heat-resistant insulator, and the heat-resistant insulator may be a heat-resistant insulator whose primary constituent is polyimide or Teflon, or both.
In the third embodiment, the insulated resistance heating element 13, the resistance heating element 13a, the insulating sheet 13b, the temperature sensor 40, the support member, the container (30), the bypass hole for allowing passage of the cable of the temperature sensor provided to the heater unit 10, the through-hole for the lifter pin for lifting up the substrate, and hole for allowing passage of the cable for energizing the insulated resistance heating element 13, the soft member, and other components can be the same as those described in the first embodiment.
With the heater unit of the first through third embodiments described above, manufacturing or inspection apparatus for semiconductor substrates or glass substrates for flat panel displays including the heater unit can be manufactured. Manufacturing or inspection devices can also be manufactured for semiconductor substrates or glass substrates for flat panel displays which include a heating and cooling device comprising the heater unit and the mobile cooling plate of the first through third embodiments.
These manufacturing and inspection apparatuses are capable of performing heating and cooling quickly without increasing heat resistance, and of reducing the bimetal-induced warping resulting from the difference in thermal expansion between the top and bottom uniform heat plates, even in conditions of severe temperature changes during rapid heating or rapid cooling. As a result, highly uniform heat properties can be constantly maintained in the substrate placed on the placement surface.
The heater unit of the present invention, the heating and cooling device including this heater unit, and the inspection apparatus or manufacturing apparatus comprising these were described above based on embodiments, but the present invention is not limited to these embodiments, and it should be understood that various modifications are possible within a range that does not deviate from the scope of the present invention. That is, the technological scope of the present invention encompasses the scope of the claims and equivalent items.
The first embodiment of the present invention is shown hereinbelow in Working Examples (1)-1 through (1)-11.
A heater unit 10 of Sample 1 was prepared, composed of the first uniform heat plate 11, the second uniform heat plate 12, and the insulated resistance heating element 13 shown in
In the insulated resistance heating element 13, a microfabricated metal foil composed of stainless steel was integrated with polyimide (PI). The thickness (C) was 0.15 mm. The insulated resistance heating element 13 was secured using screws while held between the first uniform heat plate 11 and the second uniform heat plate 12. The heater unit 10 of Sample 1 was thereby obtained. Heater units 10 of Samples 2 through 8 were prepared in the same manner, but the thicknesses of the first uniform heat plate 11 and the second uniform heat plate 12 were varied in these cases.
A mobile cooling plate 20 was placed at the bottom of the heater unit 10 in each of Samples 1 through 8.
The mobile cooling plate 20 was formed by mechanically processing a flow passage for flowing water as a refrigerant through each of two copper plates having 10 mm in thickness and 340 mm in diameter, bonding the two plates together by soldering, and attaching refrigerant passageways to their side surfaces. Nickel platings were formed on the surfaces in order to ensure heat resistance. The configurations of the heater units 10 of these Samples 1 through 8 are shown in Table 1 below.
In the heater units 10 of Samples 1 through 8 of Table 1, power was supplied to the insulated resistance heating elements 13 while the mobile cooling plates 20 were separated, heating the elements from room temperature to 150° C., after which the power supply to the insulated resistance heating elements 13 was stopped, and the mobile cooling plates 20 with water flowing through were brought in contact with the heater units 10, cooling them. The uniform heat properties of the wafer placement surfaces 11a, which had been heated to 150° C., were measured. The times required to raise the temperature from 100° C. to 150° C. and the times required to cool from 150° C. to 100° C. were measured. Furthermore, the changes in the flatness of the wafer placement surfaces 11a after temperature increase and cooling were measured. The results are shown in Table 2 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied. As for the manufacturing cost, the circle symbol indicates the manufacturing cost lower than that for a conventional heater unit consisting of one metal layer, and symbol x indicates the manufacturing cost higher than the same.
As can be seen from Table 2, satisfactory results for uniform heat properties, temperature increase rate, cooling rate, change in flatness, and manufacturing cost were achieved for the heater units 10 of Samples 1 to 3, 5, and 7. In Sample 4, in which the total (A1+A2) of the thickness (A1) of the first uniform heat plate 11 and the thickness (A2) of the second uniform heat plate 12 exceeded 1/40 of the diameter (B) of the first uniform heat plate 11, the temperature increase rate and cooling rate were time-consuming. In Sample 6, in which the thickness (A1) of the first uniform heat plate 11 was less than 1 mm, the first uniform heat plate 11 was severely warped and measurement could not be continued. In Sample 8, in which the thickness (A2) of the second uniform heat plate 12 was less than 1 mm, the second uniform heat plate 12 cracked and measurement could therefore not be continued.
Other than AlN being used for the material of the second uniform heat plate 12 instead of the Si—SiC composite, heater units 10 of Samples 9 through 16 shown in Table 3 below were prepared in the same manner as Working Example (1)-1.
In the heater units 10 of Samples 9 through 16 of Table 3, mobile cooling plates 20 were placed at the bottom in the same manner as in Working Example (1)-1, and temperature increasing and cooling were performed to measure uniform heat properties and the like in the same manner as in Working Example (1)-1. The results are shown in Table 4 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
It is clear from Table 4 that the same results as those of Working Example (1)-1 were achieved even through AlN was used as the material of the second uniform heat plate 12.
Other than SiC being used for the material of the second uniform heat plate 12 instead of the Si—SiC composite, heater units 10 of Samples 17 through 24 shown in Table 5 below were prepared in the same manner as Working Example (1)-1.
In the heater units 10 of Samples 17 through 24 of Table 5, mobile cooling plates 20 were placed at the bottom in the same manner as in Working Example (1)-1, and temperature increasing and cooling were performed to measure uniform heat properties and the like in the same manner as in Working Example (1)-1. The results are shown in Table 6 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
It is clear from Table 6 that the same results as those of Working Example (1)-1 were achieved even through SiC was used as the material of the second uniform heat plate 12.
Other than an Al—SiC composite being used for the material of the second uniform heat plate 12 instead of the Si—SiC composite, heater units 10 of Samples 25 through 32 shown in Table 7 below were prepared in the same manner as Working Example (1)-1.
In the heater units 10 of Samples 25 through 32 of Table 7, mobile cooling plates 20 were placed at the bottom in the same manner as in Working Example (1)-1, and temperature increasing and cooling were performed to measure uniform heat properties and the like in the same manner as in Working Example (1)-1. The results are shown in Table 8 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
It is clear from Table 8 that the same results as those of Working Example (1)-1 were achieved even through an Al—SiC composite was used as the material of the second uniform heat plate 12.
Other than a Al being used for the material of the first uniform heat plate 11 instead of Cu and an alumite treatment being performed instead of the Ni plating, heater units 10 of Samples 33 through 40 shown in Table 9 below were prepared in the same manner as Working Example (1)-1.
In the heater units 10 of Samples 33 through 40 of Table 9, mobile cooling plates 20 were placed at the bottom in the same manner as in Working Example (1)-1, and temperature increasing and cooling were performed to measure uniform heat properties and the like in the same manner as in Working Example (1)-1. The results are shown in Table 10 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
It is clear from Table 10 that the same results as those of Working Example (1)-1 were achieved even through Al treated with alumite was used as the material of the first uniform heat plate 11.
Other than Al being used for the material of the first uniform heat plate 11 instead of Cu, an alumite treatment being performed instead of the Ni plating, and AlN being used for the material of the second uniform heat plate 12 instead of an Si—SiC composite, heater units 10 of Samples 41 through 48 shown in Table 11 below were prepared in the same manner as Working Example (1)-1.
In the heater units 10 of Samples 41 through 48 of Table 11, mobile cooling plates 20 were placed at the bottom in the same manner as in Working Example (1)-1, and temperature increasing and cooling were performed to measure uniform heat properties and the like in the same manner as in Working Example (1)-1. The results are shown in Table 12 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
It is clear from Table 12 that the same results as those of Working Example (1)-1 were achieved even through Al treated with alumite was used as the material of the first uniform heat plate 11 and AlN was used as the material of the second uniform heat plate 12.
Other than Al being used for the material of the first uniform heat plate 11 instead of Cu, an alumite treatment being performed instead of the Ni plating, and SiC being used for the material of the second uniform heat plate 12 instead of an Si—SiC composite, heater units 10 of Samples 49 through 56 shown in Table 13 below were prepared in the same manner as Working Example (1)-1.
In the heater units 10 of Samples 49 through 56 of Table 13, mobile cooling plates 20 were placed at the bottom in the same manner as in Working Example (1)-1, and temperature increasing and cooling were performed to measure uniform heat properties and the like in the same manner as in Working Example (1)-1. The results are shown in Table 14 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
It is clear from Table 14 that the same results as those of Working Example (1)-1 were achieved even through Al treated with alumite was used as the material of the first uniform heat plate 11 and SiC was used as the material of the second uniform heat plate 12.
Other than Al being used for the material of the first uniform heat plate 11 instead of Cu, an alumite treatment being performed instead of the Ni plating, and an Al—SiC composite being used for the material of the second uniform heat plate 12 instead of an Si—SiC composite, heater units 10 of Samples 57 through 64 shown in Table 15 below were prepared in the same manner as Working Example (1)-1.
In the heater units 10 of Samples 57 through 64 of Table 15, mobile cooling plates 20 were placed at the bottom in the same manner as in Working Example (1)-1, and temperature increasing and cooling were performed to measure uniform heat properties and the like in the same manner as in Working Example (1)-1. The results are shown in Table 16 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
It is clear from Table 16 that the same results as those of Working Example (1)-1 were achieved even through Al treated with alumite was used as the material of the first uniform heat plate 11 and an Al—SiC composite was used as the material of the second uniform heat plate 12.
For the sake of reference, heating and cooling devices were prepared as Samples 65 through 67 shown in Table 17 below. Specifically, the heating and cooling device of Sample 65 was prepared in the same manner as Sample 2 of Working Example (1)-1, other than AlN being used as the material of the first uniform heat plate 11 and copper being used as the material of the second uniform heat plate 12. In the heating and cooling device of Sample 66, AlN was used as the material of the first uniform heat plate 11, the thickness (A1) of which was 6 mm, and a second uniform heat plate 12 was not provided. For the resistance heating element, a heating element circuit was formed with a tungsten paste by screen printing on the bottom side of the first uniform heat plate 11, i.e., on the side opposite the wafer placement surface 11a, and the circuit was sintered, after which a glass paste for ensuring insulation was coated over and sintered on the surface of the heating element so that the thickness of the total of the insulator and the heating element was 150 μm. In the heating and cooling device of Sample 67, copper was used as the material of the first uniform heat plate 11, the thickness (A1) of which was 6 mm, and a second uniform heat plate 12 was not provided. The insulated resistance heating element 13, which had a thickness (C) of 0.15 mm after being integrated with polyimide, was attached by adhesion to the bottom surface of the first uniform heat plate 11.
In the heating and cooling devices of Samples 65 through 67 shown in Table 17, mobile cooling plates 20 were placed at the bottom in the same manner as in Working Example (1)-1, and temperature increasing and cooling were performed to measure uniform heat properties and the like in the same manner as in Working Example (1)-1. The results are shown in Table 18 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
As can be seen from Table 18, in both of the heating and cooling devices of Samples 65 and 66, the uniform heat properties at 150° C. exceeded 0.5° C. The heating and cooling device of Sample 66 also had a high manufacturing cost because a step for screen printing the resistance heating element was required. The heating and cooling device of Sample 67 required time for the temperature increase rate and the cooling rate, and the flatness after temperature increasing and cooling had changed more than 50 μm from the flatness prior to temperature increasing and cooling.
Heater units 10 were prepared for Samples 68 through 71 shown in Table 19 below.
That is, for the heater unit 10 of Sample 68, two layers of integrated and insulated resistance heating elements 13 were stacked so as to have the structure shown in
In the heater units 10 of Samples 68 through 71 shown in Table 19, mobile cooling plates 20 were placed at the bottom in the same manner as in Working Example (1)-1, and temperature increasing and cooling were performed to measure uniform heat properties and the like in the same manner as in Working Example (1)-1. The results are shown in Table 20 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
As can be seen from Table 20, satisfactory results were achieved in the heater units 10 of Samples 68 through 70, similar to Samples 1 through 3, 5, and 7 of Working Example (1)-1, but with the heater unit 10 of Sample 71 which used a resistance heating element integrated using mica, the uniform heat properties exceeded 0.5° C. and the temperature increase rate and cooling rate were time-consuming.
Other than the flatness being varied in the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13, heater units 10 of Samples 72 through 85 were prepared in the same manner as Sample 1 of Working Example (1)-1. In the heater units 10 of Samples 72 through 85, mobile cooling plates 20 were placed at the bottom similar to Working Example (1)-1, and a heat cycle consisting of temperature increasing and cooling similar to Working Example (1)-1 was repeated 1000 times. To determine the effects the heat cycle had on the flatness and uniform heat properties of the wafer placement surface 11a, the flatness and uniform heat properties of the wafer placement surface 11a were measured after the heat cycle was completed 1 time, 100 times, 200 times, 300 times, 500 times, and 1000 times. The results are shown in Table 21 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
As can be seen from Table 21, in Samples 83 through 85 in which the flatness exceeded 100 μm in the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13, the flatness of the wafer placement surface 11a was poor as were the uniform heat properties, and the predetermined uniform heat property conditions were not successfully satisfied. In Samples 72 through 82 in which the flatness was 100 μm or less in the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13, the predetermined uniform heat property conditions were successfully satisfied even after repeating the heat cycle 1000 times. In Samples 72 through 77 in which the flatness was 50 μm or less in the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13, it can be seen that the changes in flatness of the wafer placement surface 11a due to the heat history of the heat cycle were successfully suppressed, and excellent reliability was demonstrated.
Other than the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 being given an upwardly concave or upwardly convex shape and the flatness thereof being 40 μm, heater units 10 of Samples 86 and 87 were prepared in the same manner as Sample 1 of Working Example (1)-1. For the heater units 10 of Samples 86 and 87, the heat cycle was repeated 1000 times and the flatness and uniform heat properties of the wafer placement surface 11a were determined in the same manner as Working Example (1)-10. The results are shown in Table 22 below. The circle symbol indicates that predetermined conditions shown in the table were satisfied, and the symbol x indicates that these conditions were not satisfied.
As can be seen from Table 22, changes in flatness of the wafer placement surface 11a due to the heat history of the heat cycle were successfully suppressed and excellent reliability was demonstrated in the heater units 10 of Samples 86 and 87, but the change in flatness was smaller in Sample 86 in which the surface of the second uniform heat plate 12 in contact with the insulated resistance heating element 13 had an upwardly concave shape, than in Sample 87 in which the shape was upwardly convex.
Working Examples (2)-1A through (2)-6B, which pertain to the second embodiment of the present invention, are shown hereinbelow.
The heater unit 10 shown in
Processing for substrate suction was performed in the placement surface 11a of the first uniform heat plate 11, notches for flexibility were formed by cutting in the opposite surface of the placement surface 11a, the flatness was finished to 50 μm, and an Ni plating was formed. A temperature sensor 40 for monitoring temperature was embedded in the first uniform heat plate 11. The second uniform heat plate 12 was subjected to processing in order to avoid the temperature sensor 40 or the power supply wiring, and the flatness was finished to 50 μm. The first uniform heat plate 11 and the second uniform heat plate 12 had diameters of 330 mm and thicknesses of 3 mm.
SUS foils were formed on heating element circuits for the resistance heating elements 13a, a plurality of polyimide sheets were prepared as the insulating sheet 13b, and these were stacked as shown in
Thus, heater units 10 were prepared for Samples 1A through 8A shown in Table 23 below. For all of these samples, the change in flatness of the placement surface 11a and rate of temperature increase were measured when the surface had been heated from room temperature to 200° C., both when only one of the two resistance heating elements 13a was supplied with power and heated (1.25 kW) and when both the elements were supplied with power and heated (2.5 kW). The temperature distribution was measured by a wafer thermometer, which was a temperature measuring resistance element embedded in the wafer. The measurement results and their evaluations are shown in Table 23 below. The term “determination” in the following tables (Tables 23 through 43) refers to predetermined conditions of the change in flatness being 10 μm or less, the temperature increase rate at 1.25 kW being 480 seconds or less (21.9° C./min or greater), the temperature increase rate at 2.5 kW being 240 seconds or less (43.8° C./min or greater), and the temperature distribution being 0.5° C. or less; wherein the circle symbol indicates that these conditions were satisfied and the symbol x indicates that these conditions were not satisfied. In the column “overall determination” in the table, the circle symbol indicates that all of these conditions were satisfied, and the symbol x indicates that not all of the conditions were satisfied.
Bonding means combining screws and bearings such as is shown in
The material of the first uniform heat plate 11 was selected from among the ceramics or metal-ceramic composite materials AlN, SiC, SiSiC, and AlSiC, and the material of the second uniform heat plate 12 was selected from between the metals Cu and Al, resulting in various combinations of materials. The placement surface 11a of the first uniform heat plate 11 was subjected to processing for substrate suction, and the flatness was finished to 50 μm. The surface of the second uniform heat plate 12 on the substrate side was subjected to notching for flexibility as well as processing for avoiding the temperature sensor 40 and the power supply wiring, the flatness was finished to 50 μm, and an Ni plating was formed. Otherwise, Samples 9A through 16A were prepared in the same manner as in Working Example (2)-1A, and the same measurements were taken.
The measurement results and their evaluations are shown in Table 25 below.
Bonding means combining screws and bearings such as is shown in
The first uniform heat plate 11 and the second uniform heat plate 12 were both Cu, both Al, or both AlN, otherwise the Samples 17A through 19A were created in the same manner as Working Example (2)-1A, and the same measurements as Working Example (2)-1A were taken. For the sake of further comparison, Samples 20 through 22 were prepared in the same manner as in Working Example (2)-1A, other than the second uniform heat plate 12 not being used as in conventional practice, only the first uniform heat plate 11 being used with a thickness of 6 mm, the material being Cu, Al, or AlN, and a heating element insulated with polyimide being attached and integrated with a heat-resistant adhesive to the surface of the first uniform heat plate 11 on the side opposite the placement surface 11a; and the same measurements as Working Example (2)-1A were taken. The measurement results and their evaluations are shown in Table 27 below.
Bonding means combining screws and bearings such as is shown in
As can be seen from the results of Tables 27 and 28, since the thinned uniform heat plate of metal has low rigidity, warping during the temperature increase was extensive in the cases of vacuum suctioning two plates as well as of course the cases of only one conventional metal plate in which a second uniform heat plate was not used, and sufficient uniform heat properties were not achieved.
Furthermore, the temperature increase rate was also slow in the case of Cu because of the large heat capacity.
It is clear from the results of Tables 23, 24, 25, and 26 that between the first uniform heat plate 11 and the second uniform heat plate 12, by using a metal for one, using a ceramic or a metal-ceramic composite material for the other, and bonding these two uniform heat plates together by vacuum-suction means or by bonding means combining screws and bearings via the insulated resistance heating element 13 made of insulated layers, the change in flatness can be minimized, uniform heat properties can be ensured, and a high rate of temperature increase can be achieved. It is also clear that by staking two resistance heating elements 13a, the power can be increased to twice the usual power of one resistance heating element 13a, and the temperature can be increased at twice the rate.
The first uniform heat plate 11 and the second uniform heat plate 12 were not bonded by vacuum suction means or by bonding means combining screws and bearings, but were fixed together by common screws in multiple locations, otherwise Samples 23 through 38 were prepared in the same manner as Working Example (2)-1A. These were heated from room temperature to 200° C. in the same manner as Working Example (2)-1A, and the change in flatness and temperature increase rate of the placement surfaces 11a were measured. The measurement results and their evaluations are shown in Table 29 below.
It is clear from Table 29 that in the heater units in which the first uniform heat plate 11 and the second uniform heat plate 12 were fixed by using multiple common conventional screws, there was a large change in flatness during temperature increasing and satisfactory uniform heating was not achieved at 200° C.
Processing for flexibility was not performed on the first uniform heat plate 11, otherwise the heater units of Samples 39A through 54A were prepared in the same manner as in Working Example (2)-1A, the heater units were heated from room temperature to 200° C. in the same manner as Working Example (2)-1A, and the change in flatness and temperature increase rate of the placement surfaces 11a were measured. The measurement results and their evaluations are shown in Table 30 below.
Bonding means combining screws and bearings such as is shown in
It is clear from Tables 30 and 31 that when processing for flexibility is not performed, the change in flatness during temperature increasing is greater and the uniform heat properties during temperature increasing are not as good as when this processing is performed.
Other than the thickness of the first uniform heat plate 11 being 2 mm and the thickness of the second uniform heat plate 12 being 4 mm, the heater units of Samples 55A through 62A were prepared in the same manner as in Working Example (2)-1A, and the same measurements as Working Example (2)-1A were taken. The measurement results and their evaluations are shown in Table 32 below.
Bonding means combining screws and bearings such as is shown in
These samples were heated in the same manner as in Working Example (2)-1A, and the change in flatness and temperature increase rate of the placement surfaces 11a were measured. The measurement results and their evaluations are shown in Table 33 below.
Other than the thickness of the first uniform heat plate 11 being 4 mm and the thickness of the second uniform heat plate 12 being 2 mm, the heater units of Samples 63A through 70A were prepared in the same manner as in Working Example (2)-2A, and the same measurements as Working Example (2)-1A were taken. The measurement results and their evaluations are shown in Table 34 below.
Bonding means combining screws and bearings such as is shown in
These samples were heated in the same manner as in Working Example (2)-1A, and the change in flatness and temperature increase rate of the placement surfaces 11a were measured. The measurement results and their evaluations are shown in Table 35 below.
For the sake of reference the heater unit of Sample 71 was prepared by reversing the thicknesses of the first uniform heat plate 11 and the second uniform heat plate 12 of Sample 55A in Working Example (2)-3A, and the same measurements were taken. The measurement results and their evaluations are shown in Table 36 below.
When the results of Tables 32, 33, 34, and 35 are compared to those of Tables 23, 24, 25, and 26, it is clear that making the metal less thick than the ceramic or the metal-ceramic composite material speeds up the temperature increase rate. When the metal is thicker than the ceramic as in the reference example shown in Table 36, the time showing the temperature increase rate is longer and the ceramic is too thin, which makes it impossible to maintain flatness. In other words, it is clear that thickening the ceramic and thinning the metal makes warping and other problems less likely and increases reliability.
Other than flanges being processed into the external peripheries of the first uniform heat plate 11 and the second uniform heat plate 12 as in
It is clear from Table 37 that creating an airtight seal in the external peripheries of the first uniform heat plate 11 and the second uniform heat plate 12 can increase airtightness, improve adherence between the uniform heat plates 11, 12 and the insulated resistance heating element 13, and increase the rate of temperature increase.
To prepare the heater shown in
Furthermore, a phosphorus deoxidized copper pipe 6 mm in outside diameter and 4 mm in inside diameter was formed by bending as the flow passage capable of flowing refrigerant. A counterbore was provided in the surface of the cooling plate 20 on the side opposite the surface in contact with the heater unit 10, the copper pipe was fitted into this counterbore, a thermally conductive resin was embedded in the space formed thereby, and heat was efficiently transmitted. An inlet and an outlet for supplying and discharging cooling water were formed in the ends of the flow passage. A stopper plate for supporting the flow passage was fixed in place by screwing, and the cooling plate 20 having a flow passage in its interior was completed. This cooling plate 20 was capable of being moved up and down and brought in contact with/separated from the heater unit 10 by a raising/lowering mechanism composed of an air cylinder.
Next, a container 30 was prepared from stainless steel. The side walls of the container 30 had heights of 30 mm on the inside surfaces, an inside diameter of 337 mm, and thicknesses of 1.5 mm, and the bottom surface had a thickness of 3 mm. In the bottom surface was formed an opening for fastening the power supply wiring, the temperature sensor, and a support rod for supporting the heater unit 10 in the container. The samples prepared in Working Example (2)-5, Working Example (2)-3A, and Working Example (2)-4A previously described were attached to the support rods of each of the containers 30, and the mobile cooling plates 20 were assembled with the raising/lowering mechanisms, completing the heaters. In the resulting heaters, the mobile cooling plates 20 were pressed against the heater units 10 whose temperatures had been raised and stabilized at 200° C., causing the heater units to cool rapidly, and the changes in flatness and cooling rates at 150° C. were measured. The term “determination” for the cooling rate, the circle symbol indicates a time for cooling from 200° C. to 150° C. being 60 seconds or less, and the symbol x indicates a time exceeding 60 seconds for the same. The measurement results and their evaluations are shown in Tables 38, 39, and 40 below.
The samples prepared in Working Example (2)-3B and Working Example (2)-4B previously described were attached instead of the samples prepared in Working Example (2)-3A and Working Example (2)-4A, otherwise the heaters shown in
For the sake of reference, heaters were completed in the same manner as in Working Example (2)-6A using the samples prepared in Reference Example (2)-2, and the heaters were evaluated in the same manner as in Working Example (2)-6A. The measurement results and their evaluations are shown in Table 43 below.
It is clear from Tables 38, 39, 41, 40, 42, and 43 that compared to common conventional multi-point screwing methods, the change in flatness during cooling can be kept smaller and the uniform heat properties can be increased with the second embodiment of the present invention. It is also clear that heat resistance is reduced by the force of adherence caused by the vacuum-suction means or the bonding means combining screws and bearings.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2009-284097 | Dec 2009 | JP | national |
| 2010-093408 | Apr 2010 | JP | national |
