Patent Application
20150075748
This application claims the benefit of Japanese Patent Application No. 2013-190969, filed on Sep. 13, 2013, in the Japan Patent Office, the disclosure of which is incorporated herein in its entirety by reference.
The present disclosure relates to a substrate temperature regulating device capable of regulating a temperature of a substrate at different temperature settings, and a substrate processing apparatus using the same.
A substrate such as a semiconductor wafer or the like is sometimes processed through a plurality of steps having different temperatures. For example, there is a known process of performing etching at a low temperature and then removing the etching residue at a high temperature and a process of heating a film formed on a substrate and then rapidly cooling the film.
If a process is performed that undergoes two different of temperature settings in the same chamber, throughput is reduced because time is consumed in changing the temperature setting for the chamber. For that reason, it is typical to use separate chambers that are set at different temperatures.
When separate chambers are used in this way, the footprint of an apparatus becomes larger and the cost is increased.
Under such circumstances, there have been studies for processing apparatus designs capable of increasing and decreasing the temperature within a short period of time and capable of implementing a high temperature step and a low temperature step in the same chamber. For example, one type of heating/cooling device includes a substrate support stand installed within a chamber that has a cooling function, and a halogen lamp installed in an upper region of the chamber and a quartz window installed in a top portion of the chamber. When heating the substrate, the substrate is raised upward to a heating position away from the substrate support stand. When cooling the substrate, the substrate is kept in a cooling position on the substrate support stand.
Because the heating mechanism takes up room in the top portion of the chamber, it is difficult to install a shower head, e.g., for introducing gas into the chamber, or a plasma source in the top portion of the chamber. Thus, there is less flexibility in the substrate processing.
Some embodiments of the present disclosure provide a substrate temperature regulating device capable of rapidly changing the temperature of a substrate within the chamber of a substrate processing apparatus while allowing a wide variety of substrate processes within the chamber, and a substrate processing apparatus using such as device.
According to one embodiment of the present disclosure, provided is a substrate temperature regulating device for regulating a temperature of a substrate within a chamber of a substrate processing apparatus, the device including: a mounting stand configured to mount the substrate thereon, the mounting stand including a temperature regulating medium flow path formed therein; a substrate elevating mechanism configured to move the substrate up and down between a first position defined on the mounting stand and a second position defined above the mounting stand; a first temperature regulating unit configured to supply a temperature regulating medium to the temperature regulating medium flow path and configured to regulate the temperature of the substrate to a first temperature in the first position; a second temperature regulating unit installed below the mounting stand and configured to regulate the substrate to a second temperature by emitting light toward the substrate positioned in the second position and heating the substrate, the light having a wavelength that is absorbed by the substrate; and a light transmitting window installed in the mounting stand and configured to transmit the light emitted from the second temperature regulating unit.
According to another embodiment of the present disclosure, provided is a substrate processing apparatus for processing a substrate at different temperature settings, which includes: a chamber configured to accommodate the substrate; and the aforementioned substrate temperature regulating device installed in a bottom portion of the chamber, wherein the substrate temperature regulating device is configured to regulate a temperature of the substrate at a first temperature during a first process and to a second temperature during a second process.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.
Reference will now be made in detail to various embodiments, examples of which are illustrated in the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.
A substrate temperature regulating device 100 according to an embodiment is installed in the bottom portion of the chamber of a substrate processing apparatus. The substrate temperature regulating device 100 may be configured to regulate a temperature of a substrate at different temperature settings. The substrate processing apparatus performs a first process at a first temperature of the temperature settings and a second process at a second temperature setting higher than the first temperature. The substrate processing apparatus is not particularly limited to any substrate processes. For example, etching may be the first process and then residue removal may be the second process. Likewise, the substrate itself is not particularly limited. Any kind of substrate may be involved, for example, such as a semiconductor substrate (semiconductor wafer), a flat panel display (FPD) substrate or a solar cell substrate.
The substrate temperature regulating device 100 includes a mounting stand 10 where a substrate S can be mounted, and a substrate elevating unit 20 configured to move the substrate S up and down between a first position where the substrate S can be in contact with the mounting stand 10 and a higher second position that is above the mounting stand 10. The substrate temperature regulating device 100 also includes a heating unit 30 installed below the mounting stand 10 and configured to heat the substrate S with light, a cooling unit 40 configured to cool the substrate S with coolant flowing through the mounting stand 10, and a plurality of light transmitting windows 50 configured to transmit the light emitted from the heating unit 30 to the substrate S. The mounting stand 10 is supported at the bottom portion of a chamber by a cylinder-shaped support member 60.
The mounting stand 10 may be a two-layer structure consisting of an upper plate 11 having a substrate mounting surface and a lower plate 12 arranged below the upper plate 11. The upper plate 11 is made of a metallic material with high heat conductivity, e.g., aluminum The lower plate 12 may be made of a material such as stainless steel. Within the mounting stand 10 there is a coolant flow path 41 and also transmission holes 51. The transmission holes 51 are placed where the light transmitting windows 50 are to be installed.
The substrate elevating unit 20 includes three support pins 21 (only two of which are shown in
The heating unit 30 is designed to heat the substrate S with the light emitted from a light emitting element such as an LED (Light Emitting Diode). The heating unit 30 may include a plurality of LED arrays 31 each equipped with a plurality of LEDs, a cooling plate 32 configured to support the LED arrays 31 and to cool the LEDs, and one or more power supply units 33 configured to supply electric power to the respective LED arrays 31. Instead of the LEDs, other light emitting elements such as semiconductor lasers may be used. When using a light emitting element as a heating mechanism, electromagnetic radiation (in LEDs, this is induced by the recombination of electrons and holes) is used in place of black-body radiation from a heat source. For that reason, it is possible to heat only the material that absorbs the specific wavelength of the emitted light. Moreover, when heating the substrate S in this manner, the temperature can rise and fall quickly. LEDs can emit light with wavelengths that fall within a range from ultraviolet to a near infrared (0.36 μm to 1.0 μm). LEDs may include a compound semiconductor that is based on GaN, GaAs, GaP or the like. An LED suitable for the heating unit 30 would emit light of a wavelength from within the range noted above that is not transmitted by the substrate S. From this viewpoint, it is preferable to use an LED that emits near infrared light having a wavelength of 0.8 μm to 1.0 μm. Particularly, if the substrate S is made of silicon, it is possible to efficiently heat the substrate S using the near infrared light.
The LED arrays 31 are each aligned with the light transmitting windows 50 of the mounting stand 10. The light emitted from the LED arrays 31 is transmitted through the light transmitting windows 50 and is irradiated on the substrate S in the second position, thereby heating the substrate S to the higher second temperature setting. The higher second temperature may be, for example, about 200 degrees C.
In each of the LED arrays 31, a plurality of LEDs is installed on a support body made of a material with high-heat-conductivity while also having electrical insulation properties, for example, aluminum nitride (AlN) ceramics. The support body makes contact with the cooling plate 32 through a bonding material with high heat conductivity. The cooling plate 32 is made of a metallic material having high heat conductivity, e.g., copper or aluminum A coolant flow path 34 is defined within the cooling plate 32. A coolant supply pipe 35 and a coolant discharge pipe 36 are connected to the coolant flow path 34. The cooling plate 32 is cooled by circulating a coolant composed of water or a fluorine-based liquid (trade names: FLUORINERT or GALDEN) through the coolant flow path 34 by a coolant circulating mechanism (not shown). The cooling plate 32 thus cools the support body, which in turn cools the LEDs in the LED arrays 31. Cooling the LEDs prevents the reduction in light emission that can occur when the temperature of the LEDs themselves get too hot.
A heat insulating plate 38 made of a resin, such as PTFE, is installed between the cooling plate 32 and the mounting stand 10. The heat insulating plate 38 is tightly sealed between the cooling plate 32 and the mounting stand 10. Holes 38a are placed on the heat insulating plate 38 so that the LED arrays 31 are not covered.
The cooling unit 40 includes a coolant supply pipe 42 and a coolant discharge pipe 43 connected to the coolant flow path 41 built into the mounting stand 10. A coolant circulating mechanism 44 is configured to supply a coolant to the coolant flow path 41 through the coolant supply pipe 42 and the coolant discharge pipe 43. It is preferable to use coolants that are transparent to the light emitted by the LEDs such as fluorine-based liquids (trade names: FLUORINERT or GALDEN) or water. By circulating the coolant in the coolant flow path 41 within the mounting stand 10, the mounting stand 10 is maintained at the lower first temperature setting, e.g., about 25 degrees C. When the substrate S in the first position where it is in contact with the mounting stand 10, it can be maintained at that temperature.
The light transmitting windows 50 in the mounting stand 10 are aligned with the LED arrays 31. Each of the light transmitting windows 50 includes a transmission hole 51 extending completely through the mounting stand 10, and a first light transmitting member 52 and a second light transmitting member 53 fitted into the transmission hole 51. The transmission hole 51 is composed of an upper hole 51a formed in the upper plate 11 and a lower hole 51b formed in the lower plate 12. The first light transmitting member 52 is fitted to the upper portion of the upper hole 51a such that the front surface thereof becomes flush with the front surface of the upper plate 11. The second light transmitting member 53 is fitted in the lower hole 51b. A space 54 is formed between the first light transmitting member 52 and the second light transmitting member 53 in the transmission hole 51. The space 54 serves as part of the coolant flow path 41. The coolant passing through the coolant flow path 41 cools the substrate S through the first light transmitting member 52 in the space 54. The coolant also cools the substrate S through the upper plate 11.
In order to accurately control the temperature of the substrate S by maintaining the temperature of the front surface of the first light transmitting member 52 and the front surface of the upper plate 11 close to the coolant temperature, it is preferred that the first light transmitting member 52 and the upper plate 11 are made of a material having high heat conductivity. For that purpose, sapphire, which is transparent over a wide range of light from the visible region to the infrared region and also has a heat conductivity of 42 W/m·K, is suitable for the first light transmitting member 52. As mentioned above, aluminum is suitable for the upper plate 11.
In some embodiments, to insulate the coolant flowing within the coolant flow path 41 (including the space 54) from the heating unit 30 arranged below the mounting stand 10, the second light transmitting member 53 and the lower plate 12 may be made of material with relatively low heat conductivity. Quartz, which like sapphire is transparent over a wide range of visible and infrared light, but at the same time has a lower heat conductivity of 1.4 W/m·K may be suitable as the second light transmitting member 53. As set forth above, stainless steel can be properly used as the lower plate 12. The use of quartz as the second light transmitting member 53 is advantageous in terms of cost.
As shown in
In the substrate temperature regulating device 100, as shown in
Next, the operation of the substrate temperature regulating device 100 of
A process may require the temperature of the substrate S to be set to a low first temperature setting (e.g., 25 degrees C.). When the substrate is placed in the process chamber, the support pins 21 of the substrate elevating unit 20 are raised to receive the substrate S from a transfer device (not shown). Then, the support pins 21 are lowered to place the substrate S on the mounting stand 10 in the first position as shown in
After the first process is finished at the first temperature setting, as shown in
After the second process is performed on the substrate S at the second temperature, as shown in
In some embodiments, when the temperature of the substrate S must be set to a relatively low first temperature setting, the substrate S is placed in the first position on top of the mounting stand 10. Coolant circulating through the mounting stand 10 cools the substrate S. When the temperature of the substrate S must be set at a relatively high second temperature setting, the substrate S is raised to the second position where it is no longer in contact with the mounting stand 10. Without thermally affecting the mounting stand 10, only the substrate S is heated by electromagnetic radiation from the light of the LEDs. Thus, temperature regulation can be performed in such a way that the cooling unit 40 and the heating unit 30 do not thermally affect each other. Accordingly, the temperature of the substrate S can quickly change between the first and second temperature settings. This makes it possible to increase process throughput.
In addition, the cooling unit 40 and the heating unit 30 are both installed on the same side of the substrate S as the mounting stand 10. Thus, if the substrate temperature regulating device 100 is installed in a chamber of a substrate processing apparatus, none of its components use the top portion of the chamber. Other components for substrate processing, such as a shower head for introducing gas or a plasma source, can be installed in the top portion of the chamber. It is possible to flexibly perform substrate processing within the chamber.
<Examples of Substrate Processing Apparatus using the Substrate Temperature Regulating Device>
Next, various embodiments of substrate processing apparatuses that utilize the substrate temperature regulating device according to the present disclosure will be described.
Example 1 is a substrate processing apparatus that performs non-plasma etching and then heats the substrate S to remove residue.
The exhaust unit 120 includes an exhaust pipe 121 connected to the bottom of the chamber 110, a pressure control valve (APC) 122 installed in the exhaust pipe 121 and a vacuum pump 123 configured to evacuate the inside of the chamber 110 via the exhaust pipe 121.
The shower head 130 is attached to the ceiling of the chamber 110. The shower head 130 includes a gas introduction hole 131 in the top portion, a gas diffusion space 132, and a plurality of gas spray holes 133 formed on its bottom surface.
The process gas supply system 140 is configured to supply an etching gas and an inert gas. The etching gas is used in non-plasma etching of film formed on substrate S by a previous process. The inert gas is used when thermally removing residue from substrate S and to purge the chamber 110. Gas flows from the gas introduction hole 131 into the shower head 130 through a pipe 141. Examples of etching gasses include HF gas, F2 gas and NH3 gas. Examples of the inert gasses include N2 gas and Ar gas.
In the substrate processing apparatus 200, the gate valve 112 is opened and the substrate S is loaded into the chamber 110 through the loading/unloading gate 111 by a transfer device (not shown). The substrate S (which has a film on its surface) is mounted on the mounting stand 10 (in the first position) of the substrate temperature regulating device 100. The internal pressure of the chamber 110 is adjusted to a predetermined vacuum level by the exhaust unit 120. The temperature of the substrate S mounted on the mounting stand 10 is set to the first temperature setting, e.g., 25 degrees C., by the coolant circulating through the cooling unit 40.
An etching gas is supplied from the process gas supply system 140 to the shower head 130 and introduced into the chamber 110 through the shower head 130. The film on the substrate S is etched.
After the etching is finished, an inert gas is introduced through the shower head 130 to purge the chamber 110. The inside of the chamber 110 is converted to an inert gas atmosphere by continuously introducing the inert gas. The substrate S is raised by the support pins 21 of the substrate elevating unit 20 to the second position. The LED arrays 31 irradiate the substrate S with light, thereby heating the substrate S to the second temperature setting, e.g., 200 degrees C., and this removes residue from the etching process.
After the residue removal is finished, the substrate S is lowered onto the mounting stand 10 (the first position) and cooled. The gate valve 112 is opened and the cooled substrate S is unloaded through the loading/unloading gate 111 by the transfer device.
The substrate temperature regulating device 100 can switch between temperature settings for non-plasma etching and residue removal quickly. This makes it possible to increase process throughput. The substrate temperature regulating device 100 fits in the bottom of the chamber 110 and none of its components take up room in the top of the chamber 110. Thus, the shower head 130 can be installed in the top portion of the chamber 110, and this makes it possible to uniformly supply a process gas.
Example 2 describes a substrate processing apparatus in which plasma for ashing is generated after non-plasma etching.
In this example, a plurality of microwave irradiation mechanisms 210 is installed in the top of the chamber 110 as a plasma source instead of a shower head. A ring-shaped gas introduction unit 220 is installed in the upper portion of the sidewall of the chamber 110. Process gases are introduced from the process gas supply system 140 into the chamber 110 through the gas introduction unit 220. Substrate processing apparatus 300 differs from the substrate processing apparatus 200 shown in
Each of the microwave irradiation mechanisms 210 includes a tubular axial waveguide, a planar antenna, and a tuner. The waveguide is configured to propagate microwaves generated from a microwave generator not shown here. The planar antenna is installed at the tip of the waveguide. The tuner can move the waveguide. Microwaves are irradiated from a dielectric window at the tip of the planar antenna. This generates microwave plasma within the chamber.
In the substrate processing apparatus 300, the substrate S is mounted on the substrate temperature regulating device 100 as in substrate processing apparatus 200. The temperature of the substrate S is set to the first temperature setting, e.g., 25 degrees C. Etching gas is introduced from the process gas supply system 140 into the chamber 110 through the gas introduction unit 220 and film on the substrate S is etched.
Next, the chamber 110 is purged. The substrate S is raised to the second position. The LED arrays 31 of the heating unit 30 are turned on and the substrate S is heated to the second temperature setting, e.g., 200 degrees C., with light. While a plasma gas, such as Ar gas, is introduced from the process gas supply system 140 into the chamber 110 through the gas introduction unit 220, the microwave irradiation mechanisms 210 irradiate the chamber 110, generating microwave plasma within the chamber 110. Photoresist and etching residue on the substrate S are removed by this ashing process.
After the ashing is finished, the irradiation of microwaves is stopped. The substrate S is returned to the mounting stand 10 (the first position) and cooled. The gate valve 112 is opened and the cooled substrate S is unloaded from the loading/unloading gate 111 by a transfer device (not shown).
In the substrate processing apparatus 300, the substrate temperature regulating device 100 can quickly switch between temperature settings for non-plasma etching and ashing. This increases process throughput. The substrate temperature regulating device 100 is placed in the bottom of the chamber 110 and does not take up room in the top of the chamber 110. Thus, the microwave irradiation mechanisms 210 can be installed in the top of the chamber 110. This makes it possible to effectively perform the ashing. Only one microwave irradiation mechanism 210 may be used. The plasma source is not limited to microwave irradiation mechanisms 210 but may include other plasma sources.
The present disclosure is not limited to the aforementioned embodiments and may be modified without departing from its spirit and scope. The examples for the first and second temperature settings were 25 degrees C. and 200 degrees C., respectively. The temperatures are not limited to these settings and can include other temperature settings. In one or more of the aforementioned embodiments, a coolant is used to bring the substrate S to the first temperature setting. However, if the first temperature setting is higher than room temperature, a heating medium can be used in place of the coolant. Any suitable temperature regulating medium can be used to maintain the desired first temperature setting.
The number of the light transmitting windows and the number of the LED arrays are not particularly limited and may be varied depending on the size of the substrate. Moreover, the configuration of the heating unit is not limited to the one of the aforementioned embodiments. It is only necessary that the heating unit can irradiate light with a wavelength capable of heating the substrate.
In the above examples, the top portion of the substrate processing apparatuses had either a shower head or plasma source. However, the present disclosure is not limited to these components. Other components can be installed in the top portion of the chamber for other processes.
In the above examples of the substrate processing apparatus, etching is performed at a relatively low first temperature setting and residue removal or ashing is performed at a relatively high second temperature setting. However, the present disclosure is not limited to these processes. It is only necessary that the one of the processes take place at a relatively low temperature and a second process at a relatively high temperature. It is also possible to perform the high temperature process before the low temperature process.
In the previous examples, the substrate is in contact with the surface of on the mounting stand when regulating the temperature of the substrate to the first temperature. Alternatively, the substrate may be held near the mounting stand where it is not in direct contact with the surface.
In the present disclosure, when the substrate temperature is set at the relatively lower first setting, the substrate is placed on the first position on the mounting stand. A temperature regulating medium is circulated through a flow path within the mounting stand by the first temperature regulating unit. The temperature of the substrate is regulated by heat transfer. When the substrate temperature is set to the higher second setting, the substrate is raised to a second position, away from the mounting stand. Light with a wavelength that can be absorbed by the substrate is emitted from the second temperature regulating unit. The second temperature regulating unit is located below the mounting stand, and the light is shone onto the substrate through light transmitting windows installed in the mounting stand. The substrate is heated with light to the second temperature setting. Thus, the first and second temperature regulating units can each set the substrate temperature to their desired settings without thermally affecting each other. The substrate temperature can be changed quickly within the same chamber. This improves process throughput. In addition, the first and second temperature regulating units are both installed in the vicinity of the mounting stand. Thus, if the substrate temperature regulating device is installed in the chamber of a substrate processing apparatus, it is possible to freely use the top of the chamber for substrate processing. This increases the flexibility of substrate processing within the chamber.
While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the present disclosure. Indeed, the embodiments described herein may be embodied in a variety of other forms. Furthermore, various omissions, substitutions and changes in the form of the embodiments described herein may be made without departing from the spirit of the present disclosure. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the present disclosure.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2013-190969 | Sep 2013 | JP | national |
