Patent Application
20150340254
This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2014-107557, filed on May 23, 2014; the entire contents of which are incorporated herein by reference.
Embodiments described herein relate generally to a wafer holder and a deposition apparatus.
Typically, a deposition apparatus is known in which, while a wafer holder that is holding a wafer is rotated, the wafer is heated via the wafer holder and a gas is supplied onto the wafer so that a film gets formed on the wafer by means of vapor deposition.
In such a deposition apparatus, if the temperature distribution of the wafer varies widely, there are times when the thickness of the film exhibits variability. For that reason, it would be significant if a wafer holder and a deposition apparatus can be achieved with a new configuration that enables controlling variability in the temperature distribution of the wafer.
According to an embodiment, a wafer holder includes a heat receiving portion, a heating portion, and a contact making portion. The heat receiving portion receives heat from a heat source. The heating portion heats a wafer using the heat received by the heat receiving portion. The contact making portion makes contact with an outer edge of the wafer. A heat-transfer suppressing portion is provided at least either for the contact making portion, or in between the heat receiving portion and the contact making portion, or in between the heating portion and the contact making portion.
Exemplary embodiments and modification examples are described below in detail with reference to the accompanying drawings. In the embodiments and the modification examples described below, some identical constituent elements are included. Hence, in the following explanation, the identical constituent elements are referred to by the same reference numerals, and the redundant explanation is omitted.
In a deposition apparatus 1 (a coating apparatus) illustrated in
As illustrated in
The container 2 has a tubular portion 2a (a wall portion) and a bottom wail portion 2b (a wall portion). The tubular portion 2a is formed as a cylindrical portion around the rotation center Ax. At the bottom end of the tubular portion 2a is formed the bottom wall portion 2b, and an opening at the upper end of the tubular portion 2a is covered by the gas supplying unit 5. The bottom wall portion 2b is formed to have a substantially disc-like shape.
The container 2 also includes a tubular portion 2c that is positioned on the inside of the tubular portion 2a and that is formed to have a cylindrical shape around the rotation center Ax. Moreover, the tubular portion 2c extends in the upward direction from the bottom wall portion 2b. The upper end of the tubular portion 2c is positioned on the lower side than the upper end of the tubular portion 2a. The opening at the lower end of the tubular portion 2c is closed by the bottom wall portion 2b. Moreover, the wafer holder 3 is positioned to cover the opening at the upper end of the tubular portion 2c.
The container 2 includes two chambers 2d and 2e. The chamber 2d is surrounded by the gas supplying unit 5, the wafer holder 3, and some portion (the upper portion) of the tubular portion 2c. The chamber 2e is surrounded by the wafer holder 3, the bottom wall portion 2b, and the tubular portion 2c. Moreover, the container 2 includes an exhaust passage 2f, which passes in between the tubular portion 2a and the tubular portion 2c. The upper end (the inlet) of the exhaust passage 2f opens inside the chamber 2d, and the lower end (the vent) of the exhaust passage 2f opens on the outside of the bottom wall portion 2b.
The shaft 4 runs through the bottom wall portion 2b. Moreover, the shaft 4 is rotatable with respect to the bottom wall portion 2b (the container 2). Furthermore, the shaft 4 is driven by a motor (a driving source) and rotates around the rotation center Ax. The upper end of the shaft 4 has the wafer holder 3 joined (fixed) thereto. When the shaft 4 is rotary-driven by the motor (not illustrated), the wafer holder 3 rotates as a result.
The gas supplying unit 5 is positioned on the upper side of the wafer holder 3. In the gas supplying unit 5, a plurality of nozzles (not illustrated) is formed that opens inside the chamber 2d. The gas supplying unit 5 sprays (supplies) a gas (a source gas) inside the chamber 2d through the nozzles. The gas serves as the raw material for forming a film on the wafers 100.
The heater 6 (a heat source) is positioned inside the chamber 2e. Moreover, the heater 6 is positioned on the lower side of the wafer holder 3 and is facing the wafer holder 3. As an example, the heater 6 is configured in a spiral manner around the shaft 4 (the rotation center Ax).
The cooling unit 7 is positioned inside the chamber 2e and has a flat annular appearance. In the central part of the cooling unit 7, an opening 7a (a through hole) is formed through which the shaft 4 is inserted. The cooling unit 7 is of a liquid-cooled type including an internal passage (not illustrated) through which a cooling liquid flows. The cooling unit 7 cools the neighborhood thereof in such a way that the area (space) on the lower side of the cooling unit 7 in the chamber 2e is maintained at a substantially constant temperature.
Meanwhile, a reflector 8 (a heat insulation unit) is disposed in between the cooling unit 7 and the heater 6. The reflector 8 is flat and has an annular appearance around the shaft 4. Moreover, a reflector 9 is disposed on the lower side of the cooling unit 7. The reflector 9 covers the opening 7a of the cooling unit 7 from the lower side. The reflector 9 is flat and has an annular appearance around the shaft 4.
As illustrated in
In the central part of the face 3a, a joining portion 3d is disposed and joined (fixed) to the upper end of the shaft 4.
Moreover, on the face 3b, a plurality of housing units 3e is disposed along the circumferential direction of the rotation center Ax and is spaced apart from each other. With reference to
Each housing unit 3e has a bottom face 3e2 (a face) and has a face 3e3 that extends in the upward direction from the bottom face 3e2. Herein, the bottom face 3e2 is formed in a circular shape. Moreover, the bottom face 3e2 has convex supporting members 3e4 (claws) disposed thereon. The supporting members 3e4 are disposed on the outer edge of the bottom face 3e2 and are spaced apart from each other along the circumferential direction of the corresponding housing unit 3e. The wafer 100 is mounted on the supporting members 3e4. Thus, the supporting members 3e4 support the outer edge of the face 100b of the wafer 100. As illustrated in
As illustrated in
Meanwhile, in the first embodiment, the wafer holder 3 is configured by joining a single member 31 (a first-type member) and members 32 (second-type members, see
As illustrated in
Each member 32 includes a pair of fitting members 32a (see
Meanwhile, the member 31 is made of a different material than the material of the members 32. The material of the members 32 has a lower thermal conductivity than the thermal conductivity of the material of the member 31. For example, the member 31 is made of carbon, while the members 32 are made of quartz. As another example, the member 31 may be made of silicon carbide or may be manufactured by having a coat of silicon carbide on the surface of a base material made of carbon. The members 32 represent an example of the portion having a low thermal conductivity than the other portion (the member 31), and represent an example of the portion having a different material than the other portion (the member 31). Meanwhile, the materials of the member 31 and the members 32 are not limited to the materials given above.
In the wafer holder 3 having the configuration explained above, the face 3a (a heat receiving portion) receives the heat emitted by the heater 6 (a heat source). Then, the heat received by the face 3a is transferred to the bottom face 3e2. Using the heat received by the face 3a, the bottom face 3e2 (a heating portion) heats each wafer 100. More specifically, the heat released from the bottom face 3e2 is transferred to the face 100b of each wafer 100 via the inside of the depression 3e1. At that time, the heat received by the face 3a is transferred also to the portion of the wafer holder 3 other than the bottom face 3e2. In the first embodiment, in order to curb the transfer of heat to each wafer 100 from the contact face 3e6 which is making contact with the outer edge 100c of the concerned wafer 100; the depression 3e7 (see
Explained below with reference to
Given below is the explanation of the operations (a deposition method, a film formation method, and a wafer processing method) performed by the deposition apparatus 1. In the deposition apparatus 1, a film is formed on the face 100a by means of vapor deposition (chemical vapor deposition). More particularly, in the deposition apparatus 1, while the wafer holder 3 is rotated with the wafers 100 housed in the depressions 3e1, the wafers 100 are heated via the wafer holder 3 by the heat released from the heater 6. Moreover, in the deposition apparatus 1, a gas is supplied from the gas supplying unit 5 into the chamber 2d. Then, the gas supplied into the chamber 2d reacts on the face 100a of each wafer 100 thereby resulting in the formation (deposition) of a film (not illustrated) on the face 100a. The gas that does not get transformed into the film is discharged from the exhaust passage 2f. During these operations, since each wafer 100 rotates around the rotation center Ax, the gas flows along the face 100a so that uniform formation of the film on the face 100a is achieved with ease. In the deposition apparatus 1, as a result of forming a film in a repeated manner, a plurality of films can be laminated on the face 100a. In that case, in the deposition apparatus 1, it is possible to have different gases serving as the raw materials for forming different films. Meanwhile, depending on the difference in the linear coefficient of expansion of the films and the linear coefficient of expansion of the wafer 100 or depending on the difference in the linear coefficients of expansion among the films, there are times when the wafers 100 get warped (see
As described above, in the first embodiment, in the wafer holder 3, the depression 3e7, the member 32, and the gaps 3f that serve as heat-transfer suppressing portions are provided at least either for the contact face 3e6, or in between the face 3a (a heat receiving portion) and the contact face 3e6, or in between the heater 6 (a heat source) and the contact face 3e6 for the purpose of holding down the heat transfer. As a result, it becomes possible to hold the transfer of heat from the face 3a and the bottom face 3e2 to the wafer 100 via the contact face 3e6. Hence, in each wafer 100, the temperature of the portion making contact with the contact face 3e6 can be prevented from rising locally, thereby making it possible to hold down the variability in the temperature distribution of the wafer 100.
In the first embodiment, due to the centrifugal force, each wafer 100 is pressed against the contact face 3e6. Moreover, because of the centrifugal force, each wafer 100 may undergo deformation in such a way that the contact area between the contact face 3e6 and the wafer 100 increases, or there may be an increase in the degree of adhesion between the contact face 3e6 and the wafer 100. Consequently, there occurs an increase in the contact area between the wafer 100 and the contact face 3e6. However, in the first embodiment, the transfer of heat from the contact face 3e6 to the wafer 100 can be held down as described above. Therefore, even if there is an increase in the contact area between the wafer 100 and the contact face 3e6 due to the centrifugal force, it becomes possible to hold down the variability in the temperature distribution of the wafer 100. Meanwhile, the supporting members 3e4 are also making contact with the wafer 100. However, since the contact area between the supporting members 3e4 and the wafer 100 is smaller as compared to the contact area between the contact face 3e6 and the wafer 100, there is comparatively less transfer of heat from the supporting members 3e4 to the wafer 100. For that reason, the effect of the contact between the supporting members 3e4 and the wafer 100 on the temperature distribution of the wafer 100 is small enough to be ignorable. Moreover, since the centrifugal force does not cause pressing of the wafer 100 against the supporting members 3e4, the contact area between the supporting members 3e4 and the wafer 100 is less likely to increase. Even so, heat-transfer suppressing portions may be provided corresponding to the supporting members 3e4 too.
Moreover, in the first embodiment, the bottom face 3e2 is positioned separated from the wafer 100 in the thickness direction of the wafer 100. Since the bottom face 3e2 is separated from the wafer 100, it becomes possible to hold down excessive transfer of heat to the wafer 100 as compared to a configuration in which the bottom face 3e2 is wholly making contact with the wafer 100. Furthermore, in a configuration in which the bottom face 3e2 is wholly making contact with the wafer 100, if the wafer 100 gets warped, then the bottom face 3e2 and the face 100a of the wafer 100 become partially separated from each other. That leads to variability in the transfer of heat from the bottom face 3e2 to the wafer 100. In contrast, in the first embodiment, the bottom face 3e2 is positioned separated from the wafer 100 in the thickness direction of the wafer 100. Therefore, it becomes possible to prevent variability in the transfer of heat to the face 100a of the wafer 100.
Moreover, the depression 3e7 and the member 32 are disposed in the shortest route joining the face 3a and the contact face 3e6. As a result, it becomes possible to hold down the transfer of heat from the face 3a to the contact face 3e6.
Meanwhile, in the first embodiment, the explanation is given for an example in which the member 31 and the members 32 are made of mutually different materials. However, alternatively, the member 31 and the members 32 may be made of the same material. As long as the member 31 and the members 32 are made of a material such as carbon, silicon carbide, or quartz; it serves the purpose. In such a configuration too, because of the depression 3e7 and the gaps 3f, it becomes possible to hold down the transfer of heat from the face 3a and the bottom face 3e2 to the wafer 100 via the contact face 3e6. Therefore, in each wafer 100, the temperature of the portion making contact with the contact face 3e6 can be prevented from rising locally, thereby making it possible to hold down the variability in the temperature distribution of the wafer 100.
As illustrated in
In such a configuration, because of the gaps 3f and the space 3g1, the transfer of heat from the face 3a and the bottom face 3e2 to the contact face 3e6 is held down. That makes it possible to hold down the transfer of heat from the contact face 3e6 to the wafer 100. Consequently, in each wafer 100, the temperature of the portion making contact with the contact face 3e6 can be prevented from rising locally, thereby making it possible to hold down the variability in the temperature distribution of the wafer 100.
As illustrated in
In a second embodiment, as illustrated in
The first-type material portion 3h includes the face 3a, the face 3b, the bottom face 3e2, and the contact face 3e6. The second-type material portion 31 includes some part of the face 3e3. Moreover, the second-type material portion 3i is sandwiched between the first-type material portion 3h in the vertical direction.
The second-type material portion 3i is made of a material having a lower thermal conductivity than the material of the first-type material portion 3h. That is, the second-type material portion 3i has a lower thermal conductivity than the first-type material portion 3h. For example, the first-type material portion 3h is made of carbon, while the second-type material portion 3i is made of quartz. Herein, the second-type material portion 3i represents an example of the portion having a lower thermal conductivity than the other portion (the first-type material portion 3h), as well as represents an example of the portion made of a different material than the other portion (the first-type material portion 3h). Moreover, at least some portion of the second-type material portion 3i is positioned in the space ranging from the face 3a and the bottom face 3e2 up to the contact face 3e6.
In such a configuration, because of the second-type material portion 3i, the transfer of heat from the face 3a and the bottom face 3e2 to the contact face 3e6 is held down. That makes it possible to hold down the transfer of heat from the contact face 3e6 to the wafer 100. Consequently, in each wafer 100, the temperature of the portion making contact with the contact face 3e6 can be prevented from rising locally, thereby making it possible to hold down the variability in the temperature distribution of the wafer 100.
In a third embodiment, as illustrated in
In such a configuration, because of the grid-like structure 3j, the transfer of heat from the face 3a and the bottom face 3e2 to the contact face 3e6 is held down. That makes it possible to hold down the transfer of heat from the contact face 3e6 to the wafer 100. Consequently, in each wafer 100, the temperature of the portion making contact with the contact face 3e6 can be prevented from rising locally, thereby making it possible to hold down the variability in the temperature distribution of the wafer 100.
In a fourth embodiment, as illustrated in
Herein, although the invention is described with reference to the abovementioned embodiments for a complete and clear disclosure, the appended claims are not to be thus limited but are to be construed as embodying all modifications and alternative constructions that may occur to one skilled in the art that fairly fall within the basic teaching herein set forth. Moreover, the specifications regarding the configuration, the shape, and the display elements (structure, type, direction, shape, size, length, width, thickness, height, number, arrangement, position, material, etc.) can be suitably modified. Meanwhile, the heat-transfer suppressing portion may represent, for example, a parallel arrangement of a plurality of columnar members. Alternatively, the heat-transfer suppressing portion may be configured in a porous manner. Still alternatively, the heat-transfer suppressing portion may be configured in a reticulated manner. Meanwhile, the number of housing units 3e in the wafer holder 3 is not limited to three as illustrated in
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 inventions. Indeed, the novel 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 inventions. The accompanying claims and their equivalents are intended to cover such forms or modifications as would fall within the scope and spirit of the inventions.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2014-107557 | May 2014 | JP | national |
