JP2012146935A - Wafer processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold a sapphire substrate thicker than a silicon wafer on a wafer stage, e.g. a lower electrode, so that the clearance to a wafer mounting surface of the lower electrode ensures a uniform temperature during the processing of the sapphire substrate in a plasma etching apparatus.SOLUTION: A plasma etching apparatus which processes a wafer mounted on a stage in a chamber for processing a wafer comprises a clamp section 110 as a wafer holding section for holding a wafer Wa to be fixed onto a lower electrode 120a as the stage, and a heat exchange section exchanging heat with the wafer so that the temperature of the wafer Wa fixed onto the lower electrode is held constant. The lower electrode is configured so that the wafer mounting surface has a shape tailored to the warpage characteristics of a sapphire wafer.

Description

  The present invention relates to a wafer processing apparatus, and more particularly, to a structure of a lower electrode as a stage on which a wafer is placed in a wafer processing apparatus such as plasma etching.

  In the conventional dry etching apparatus, the wafer is fixed in the dry etching apparatus by holding the wafer placed on the lower electrode, which is a wafer stage, with a clamp.

  FIG. 3 is a cross-sectional view showing a schematic configuration of an etching apparatus disclosed in Patent Document 1, for example.

  In FIG. 3, the chamber 1 is provided with a gas introduction pipe 2 for introducing an etching gas and a gas exhaust pipe 3 for exhausting a reaction gas.

  Further, the chamber 1 is provided with an upper electrode 4 and a lower electrode 7 for generating plasma P1 in the chamber 1. The upper electrode 4 is connected to the RF power source 13, and the lower electrode 7 is interposed via the insulating layer 6. A heater 8 that heats the wafer W is built in the lower electrode 7 that is installed on the wafer mounting table 5.

  A ring-shaped wafer clamp 9 is provided on the lower electrode 7 via a clamp lifter 12 that moves the wafer clamp 9 up and down. The wafer clamp 9 is provided with a claw member 9a that holds the wafer from above by point contact. It has been.

  The wafer clamp 9 has a built-in heater 10 for heating the wafer clamp 9, and a thermistor 11 for detecting the temperature of the wafer clamp 9 or the wafer W is attached to the tip of the claw member 9a.

  4A is a plan view showing a schematic configuration of the wafer clamp of FIG. 3, and FIG. 4B is a cross-sectional view taken along line AA of FIG. 4A.

  In FIG. 4, the wafer clamp 9 is configured in a ring shape corresponding to the outer periphery of the wafer W, and a claw member 9 a that holds the outer peripheral portion of the wafer W by point contact is provided on the inner periphery of the wafer clamp 9. .

  The wafer clamp 9 and the claw member 9a can be made of an insulator such as ceramic. The wafer clamp 9 includes a heater 10 for heating the wafer clamp 9.

  Further, a temperature detecting means for detecting the temperature of the wafer clamp 9 or the wafer W is provided at the tip of the claw member 9a, and for example, the thermistor 11 can be used as the temperature detecting means.

  In FIG. 3, the RF power source 13 is connected to an RF power source control device 14 that performs on / off control of the RF power source 13, and the temperature control device 15 includes the heaters 8 and 10, the thermistor 11, and the RF power source control device. 14.

  The temperature control device 15 controls the temperature of the heater 10 based on the on / off control of the RF power supply 13 by the RF power supply control device 14, and based on the detection result of the surface temperature of the wafer W by the thermistor 11. The temperature of the heater 8 is controlled.

  In the etching apparatus described in Patent Document 1, the temperature of the wafer clamp 9 is monitored and the temperature of the wafer clamp 9 is controlled to suppress the expansion / contraction of the reaction product adhering to the wafer clamp 9. Thus, peeling of the reaction product attached to the wafer clamp 9 is suppressed, and the amount of the reaction product attached to the wafer clamp 9 is stabilized.

  By the way, there are some etching apparatuses which control the temperature of the wafer by injecting a cooling gas refrigerant onto the wafer from a gas injection port formed in the lower electrode.

  FIG. 5 is a view for explaining a wafer clamp apparatus used in the etching apparatus having such a configuration.

  The wafer clamp apparatus 200 includes a base member 201 to which a lower electrode 220 of an etching apparatus is attached, and a clamp portion 210 provided on the base member.

  Here, the base member 201 is provided with an actuator 213 that drives the elevating shaft 212 to move the clamp arm 211 attached to the elevating shaft 212 up and down.

  In addition, the lower electrode 220 has a surface curved in a convex shape, and a plurality of gas ejection holes 211a are provided on the surface, for example, on the outer circumference. A hole 211b is provided on the inner circumference. An outer annular groove 223a is formed between the outer circumference and the inner circumference, and an inner annular groove 223b is formed further inside the inner circumference where the gas ejection holes 211b are arranged. ing. The grooves are provided so that the gas ejected from the gas ejection holes spreads uniformly in the circumferential direction and the radial direction. Further, a gas discharge port 224 is formed at the center of the lower electrode.

  In such a wafer clamp apparatus 200, with the wafer Wb placed on the lower electrode 220, the clamp arm 211 is lowered and the peripheral edge of the wafer Wb is pressed toward the lower electrode, so that the wafer Deforms to be in close contact with the surface of 220.

  After fixing the wafer to the lower electrode 220 in this manner, plasma etching is started, and at the same time, the refrigerant gas is ejected from the gas ejection holes and is also ejected from the gas ejection holes. Heat exchange is performed with the refrigerant gas, and the wafer is cooled to be maintained at a predetermined temperature.

JP 2004-111468 A

  However, in the above-described conventional wafer clamp apparatus, when the warp characteristic of the wafer does not match the curvature of the lower electrode, a gap is formed between the wafer Wb and the peripheral portion of the lower electrode as shown in FIG. There was a problem that refrigerant gas leaked.

  For example, in a wafer clamp apparatus having a lower electrode with a curvature that assumes a silicon wafer, the above-described problem occurs when an attempt is made to clamp a sapphire substrate or the like.

  In order to avoid such a problem, it is also conceivable to flatten the wafer mounting surface as the lower electrode as shown in FIG.

  In FIG. 5B, reference numerals 321a and 321b denote a plurality of gas ejection holes, which correspond to the plurality of gas ejection holes 211a and 221b in FIG. 5A. Reference numeral 324 denotes a gas exhaust port, which corresponds to the gas exhaust port 224 in FIG. 5A. Further, 323a and 323b are an outer annular groove and an inner annular groove, and FIG. Corresponds to the outer annular groove 223a and the inner annular groove 223b.

  However, when a curved wafer having a convex shape is placed on the lower electrode having a flat wafer placement surface as shown in FIG. 5B, the peripheral edge of the wafer is clamped by a clamp arm. Even if it is pressed and fixed to the lower electrode, a wide gap is formed between the wafer and the wafer mounting surface of the lower electrode at the center of the wafer.

  For this reason, during the wafer etching process, a temperature difference occurs between the wafer center and the peripheral edge of the wafer, causing a problem that the wafer etching process cannot be made uniform within the wafer surface.

  The present invention has been made to solve the above-described problems. A sapphire substrate thicker than a silicon wafer is placed on a wafer stage such as a lower electrode, and a gap between the lower electrode and a wafer mounting surface is provided. An object of the present invention is to obtain a wafer processing apparatus capable of holding a sapphire substrate at a uniform temperature during processing.

  A wafer processing apparatus according to the present invention includes a chamber for performing processing on a wafer, and a stage provided in the chamber, on which the wafer is placed, and holds the wafer at an appropriate temperature. A wafer processing apparatus for processing the wafer while holding the wafer so that the wafer is fixed on the stage, and so that the temperature of the wafer fixed on the stage is held uniformly. A heat exchanging section for exchanging heat with the wafer, and the stage has a shape that matches the warp characteristic of the sapphire wafer with the shape of the wafer mounting surface. Achieved.

  According to the present invention, in the wafer processing apparatus, the sapphire wafer preferably constitutes a semiconductor light emitting element.

  According to the present invention, in the wafer processing apparatus, the stage has a wafer mounting surface having a convex curved surface, and the wafer holding portion has a wafer mounting portion of the stage at a central portion of the wafer. It is preferable that the peripheral portion of the wafer is pressed and fixed on the stage so that the peripheral portion of the wafer contacts the peripheral portion of the wafer mounting portion of the stage.

  According to the present invention, in the wafer processing apparatus, the heat exchange unit includes a gas supply mechanism that supplies a gaseous heat exchange medium to a gap between the wafer placement surface of the stage and the wafer pressed and fixed thereon. It is preferable to have.

  According to the present invention, in the wafer processing apparatus, the gaseous medium is preferably He gas.

  According to the present invention, in the wafer processing apparatus, the processing of the wafer is preferably a plasma etching process.

  According to the present invention, in the wafer processing apparatus, the stage constitutes a lower electrode of a pair of upper and lower electrodes for applying high-frequency power so that plasma is generated in the chamber, The curvature of the convex surface facing the wafer is preferably a curvature at which the temperature of the wafer becomes uniform by heat exchange with the wafer by the gaseous medium.

  According to the present invention, in the wafer processing apparatus, the curvature of the lower electrode having an appropriate shape for keeping the wafer temperature uniform is a ratio of the convex gap, which is the height at the center of the lower electrode to the radius of the lower electrode P is preferably set to satisfy 0.001 ≦ P ≦ 0.008.

  According to the present invention, in the wafer processing apparatus, the curvature of the lower electrode having an appropriate shape for keeping the wafer temperature uniform is a ratio of the convex gap, which is the height at the center of the lower electrode to the radius of the lower electrode It is preferable that P is set to satisfy 0.001 ≦ P ≦ 0.004.

  According to the present invention, in the above wafer processing apparatus, the curvature of the lower electrode having an appropriate shape for keeping the wafer temperature uniform is such that the ratio P of the convex gap to the radius of the lower electrode is 0.001 ≦ P ≦ 0.0021. It is preferable to set so as to be.

  According to the present invention, in the wafer processing apparatus, the lower electrode has at least a gas ejection port on a surface thereof, the gas ejection port ejecting the gaseous medium, and the gas ejection port ejecting the ejected gas. It is preferable that a plurality of annular grooves be formed concentrically so that the gas ejected from the gas ejection port spreads uniformly in the circumferential direction.

  Next, the operation of the present invention will be described.

  In the present invention, in a wafer processing apparatus for processing a wafer by placing the wafer on a stage of a chamber for processing the wafer, the wafer is held so that the wafer is fixed on the stage. A wafer holding unit and a heat exchanging unit for exchanging heat with the wafer so that the temperature of the wafer fixed on the stage is uniformly held, and the stage has a surface on which the wafer is placed. Since the shape is matched to the warp characteristics of the sapphire wafer, a thicker sapphire substrate than the silicon wafer is placed on the wafer stage such as the lower electrode, and the gap between the lower electrode and the wafer mounting surface is being processed. The temperature can be adjusted and maintained so as to be uniform.

  As described above, according to the wafer processing apparatus of the present invention, the sapphire substrate thicker than the silicon wafer is placed on the wafer stage such as the lower electrode, and the gap between the lower electrode and the wafer mounting surface is being processed on the sapphire substrate. There is an effect that the temperature can be kept uniform.

FIG. 1 is a view for explaining a plasma etching apparatus (wafer processing apparatus) according to Embodiment 1 of the present invention, and FIG. 1 (a) shows a main configuration of a wafer clamping apparatus used in the plasma etching apparatus. FIG. 1B is a cross-sectional view, and FIG. 1B is a plan view showing a lower electrode (wafer stage) constituting the clamping device. FIG. 2 is a diagram illustrating a modification of the plasma etching apparatus according to the first embodiment of the present invention. FIG. 3 is a cross-sectional view showing a schematic configuration of the etching apparatus disclosed in Patent Document 1. As shown in FIG. FIG. 4 is a diagram for explaining the conventional wafer clamper shown in FIG. 3. FIG. 4 (a) is a plan view showing a schematic configuration of the clamper, and FIG. 4 (b) is a cross-sectional view of FIG. It is sectional drawing cut | disconnected by A line. FIG. 5 is a diagram for explaining another wafer clamp apparatus used in a conventional etching apparatus. FIG. 5 (a) is a diagram for explaining the problem and FIG. 5 (a) is a countermeasure for the problem. It is a figure explaining. FIG. 6 is a diagram for explaining the curvature of the lower electrode in the plasma etching apparatus according to the first embodiment of the present invention. FIG. 6A shows the definition of the curvature of the lower electrode, and FIG. FIG. 6C shows the relationship between the curvature of the lower electrode and He leak, and FIG. 6C shows the relationship between the curvature of the lower electrode and in-plane variation in wafer temperature.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a view for explaining a plasma etching apparatus (wafer processing apparatus) according to Embodiment 1 of the present invention, and FIG. FIG. 1B is a plan view showing a lower electrode (wafer stage) constituting the clamping device.

  Similar to the conventional plasma etching apparatus shown in FIG. 3, the plasma etching apparatus according to Embodiment 1 of the present invention includes a chamber for performing processing on a wafer, and a stage (in which the wafer is placed). And processing the wafer while maintaining its surface at an appropriate temperature.

  The plasma etching apparatus of the first embodiment has a wafer clamp apparatus 100 shown in FIG. The wafer clamp apparatus 100 includes a wafer holding unit that holds the wafer so that the wafer is fixed on the stage.

  The plasma etching apparatus also includes a heat exchange unit that exchanges heat with the wafer so that the temperature of the wafer fixed on the stage is uniformly maintained. Here, the wafer is a sapphire wafer constituting a semiconductor light emitting device, and this sapphire wafer is thicker and harder than a silicon wafer.

  And in this Embodiment 1, the lower electrode 120a which is a stage has an external cylindrical shape, and makes the shape of the wafer mounting surface which is the upper surface the shape matched with the curvature characteristic of the sapphire wafer.

  Specifically, the lower electrode 120a has a wafer mounting surface with a convex curved surface, and the wafer clamp apparatus 100 has a central portion of the wafer Wa of the wafer mounting portion of the lower electrode. The peripheral edge of the wafer is pressed and fixed on the stage so that the peripheral edge of the wafer contacts the peripheral edge of the wafer mounting portion of the lower electrode 120.

  The wafer clamp apparatus 100 includes a base member 101 to which a lower electrode 120 of an etching apparatus is attached, and a clamp part 110 as the wafer holding part provided on the base member.

  Here, the base member 101 constituting the clamp unit 110 is provided with an actuator 113 that drives the elevating shaft 112 to elevate and lower the clamp arm 111 attached to the elevating shaft 112.

  The heat exchanging unit includes a gas supply mechanism that supplies a gaseous heat exchange medium to a gap between the wafer mounting surface of the stage and the wafer pressed and fixed thereon. That is, on the surface of the lower electrode 120a, for example, a plurality of gas ejection holes 121a are provided on one outer circumference, and a plurality of gas ejection holes 121b are provided on the inner circumference. An outer annular groove 123a is formed between the outer circumference and the inner circumference, and an inner annular groove 123b is formed further inside the inner circumference where the gas ejection holes 121b are arranged. ing. These grooves are provided so that the gas ejected from the gas ejection holes spreads uniformly in the circumferential direction and the radial direction. Further, a gas discharge port 124 is formed at the center of the lower electrode. The gaseous medium is preferably He gas.

  In the plasma etching apparatus of this embodiment, an upper electrode and an RF power source are provided together with the lower electrode as in the conventional plasma etching apparatus shown in FIG.

  These electrodes constitute a pair of upper and lower electrodes for applying high-frequency power so that plasma is generated in the chamber. The curvature of the convex surface of the lower electrode facing the wafer is the temperature of the wafer. However, the curvature becomes uniform by heat exchange with respect to the wafer by the gaseous medium.

  FIG. 6 is a diagram for explaining the curvature of the lower electrode in the plasma etching apparatus according to the first embodiment of the present invention. FIG. 6A shows the definition of the curvature of the lower electrode, and FIG. FIG. 6C shows the relationship between the curvature of the lower electrode and He leak, and FIG. 6C shows the relationship between the curvature of the lower electrode and in-plane variation in wafer temperature.

  That is, in FIG. 6, when an apparatus for manufacturing an LSI (semiconductor integrated circuit) using a silicon wafer is used for manufacturing an LED (light emitting diode) using a sapphire wafer, an appropriate range of curvature of the lower electrode is shown. Show.

  Here, the lower electrode has a cylindrical shape as can be seen from FIGS. 1A and 1B, and the curvature of the lower electrode is y (the lower electrode wafer is placed as shown in FIG. 6A). (The height at the center of the upper surface) / x (the radius of the upper surface of the lower electrode on which the wafer is placed).

  First, in FIG. 6B, the range of the appropriate curvature of the lower electrode is shown by using the leakage amount of He gas (He leakage%) supplied to the space between the surface of the lower electrode and the back surface of the wafer as a guide. ing. Here, the He leak% indicates (set pressure−actual pressure) / set pressure, and the graph of FIG. 6B shows the change in He leak% when the curvature of the lower electrode is changed. Yes.

  That is, in the plasma etching apparatus used for manufacturing LSI, the pressure of He gas supplied to the space between the surface of the lower electrode and the back surface of the wafer is measured by a pressure sensor (not shown). When the leak% is normally 10% or more as shown in FIG. 6B, it is determined that the leak is NG (leak state is defective), and the etching process is stopped. Here, the value (10%) of He leak% as a criterion for determining whether the leak state is good or not is usually about 10%, although it varies slightly depending on the model of the plasma etching apparatus.

  Therefore, even when the plasma etching apparatus used for manufacturing this LSI is diverted to LED manufacturing, it is necessary to set the curvature of the lower electrode so that the He leak% is 10% or less, and the plasma used here. From the measurement result (FIG. 6B) for the etching apparatus, it can be seen that it should be 0.008. That is, in this plasma etching apparatus, by setting the curvature of the lower electrode to 0.008 or less, the He leak% becomes 10% or less, and the leak OK (leak state is good) is determined as the determination of the leak state. Then, the etching process is performed.

  Further, the graph of FIG. 6C shows the temperature variation (Max-Min) in the wafer surface when the curvature of the lower electrode is changed, that is, the difference between the maximum temperature and the minimum temperature (hereinafter referred to as wafer temperature in-plane variation). Change).

  Here, in measuring the temperature, a thermo label whose mark density changes according to the temperature is attached to the surface of the wafer mounted on the lower electrode, and the wafer is based on the change in mark density of the thermo label. The temperature at the portion where the thermo label is attached is detected.

  Further, when the wafer temperature in-plane variation is 20 ° C. or more as shown in FIG. 6C, it is determined that the temperature variation is NG (temperature in-plane uniformity is not good). Here, the reference value for determining whether or not the temperature variation is good is used for the LSI processing because the allowable value as the wafer temperature in-plane variation in the plasma etching apparatus when processing the LSI is about 20 ° C. Even when the plasma etching apparatus is used for LED processing, the temperature is set to 20 ° C.

  Therefore, even when the plasma etching apparatus used for manufacturing the LSI is diverted to the manufacture of the LED, the in-plane variation of the wafer temperature is 20 ° C. by setting the curvature of the lower electrode in the range of 0.001 to 0.008. As a result, temperature variation OK (a state where the in-plane uniformity of the wafer temperature is good) can be achieved.

  Even if the curvature of the lower electrode is too small or too large, the variation in the wafer temperature plane increases because the wafer warpage occurs in the sapphire wafer, so that the shape of the upper surface of the lower electrode approaches flat. In some cases, or even when the shape of the upper surface of the lower electrode is greatly curved compared to the warp of the sapphire wafer, the gap between the lower electrode and the wafer becomes large and the cooling of the wafer by the lower electrode becomes insufficient. It is.

  As a result, it is appropriate to set the curvature of the lower electrode so that the ratio P of the convex gap to the radius of the lower electrode is in the range of 0.001 or more and 0.008 or less. In particular, the curvature of the appropriately shaped lower electrode that keeps the wafer temperature uniform may be set so that the ratio P of the convex gap to the radius of the lower electrode is in the range of 0.001 <P ≦ 0.004. Further, the curvature of the lower electrode is more preferably set so that the ratio P of the convex gap to the radius of the lower electrode is in the range of 0.001 <P ≦ 0.0021.

  Next, the operation will be described.

  In such a wafer clamp apparatus 100, with the wafer Wa placed on the lower electrode 120a, the clamp arm 111 is lowered to press the peripheral edge of the wafer Wa toward the lower electrode, so that the wafer Wa The electrode 120a is deformed to be in close contact with the surface of the electrode 120a.

  After the wafer Wa is fixed to the lower electrode 120a in this way, plasma etching is started, and at the same time, the refrigerant gas is ejected from the gas ejection holes and discharged from the gas ejection holes, thereby overheating the wafer by the etching process. Heat exchange is performed between the gas and the refrigerant gas, and the wafer is cooled so as to be maintained at a predetermined temperature.

  Hereinafter, the function and effect of the present invention will be described.

  Conventionally, when LSI equipment for manufacturing a semiconductor device using a silicon wafer is used as it is as an LED manufacturing apparatus using a sapphire wafer, a clamp holding system for fixing and holding the wafer to a lower electrode of a chamber of a plasma etching apparatus is particularly suitable. When diverted, there is a problem that due to the warp characteristics of sapphire, He leak which is a refrigerant gas on the back surface of the wafer occurs, and the wafer cooling effect becomes insufficient.

  In addition, when new LED equipment is introduced, there is a problem that initial cost is generated and cost competitiveness is lowered.

  Therefore, in the present invention, in order to improve the effective utilization of equipment and the stabilization of the in-plane processing in the production of blue LEDs, the wafer cooling effect is obtained by the characteristics of the sapphire wafer when diverting the LSI equipment to 6-inch LED production. The problem that it is insufficient and it is difficult to ensure in-plane uniformity is solved by matching the shape (convex curvature) of the lower electrode with the warp characteristics of sapphire.

  In other words, in the present embodiment, by making the curvature of the lower electrode in accordance with the warp characteristics of sapphire, He leakage of the cooling medium can be eliminated, wafer cooling efficiency can be ensured, and etching characteristics (uniformity) are improved. As a result, the LSI equipment can be diverted to the LED equipment, and the initial cost can be reduced.

  As described above, in the first embodiment, in the plasma etching apparatus for processing a wafer by placing the wafer on a stage of a chamber for processing the wafer, the wafer Wa is placed on the stage (lower part). Electrode) Heat for exchanging heat between the wafer holding unit (clamping unit) 110 to be fixed on 120a and the wafer so that the temperature of the wafer fixed on the stage is uniformly maintained. Since the lower electrode 120a is configured so that the shape of the wafer mounting surface matches the warping characteristics of the sapphire wafer, the sapphire wafer that is thicker and harder than the silicon wafer is used as the lower electrode. A gap between the lower electrode and the wafer mounting surface is held on the wafer stage so that the temperature during the processing of the sapphire wafer is uniform. Theft is possible.

  In the first embodiment, the surface shape of the lower electrode is a convex and smoothly curved shape. However, the surface shape of the lower electrode is flat and has no curvature at the center portion of the lower electrode as shown in FIG. It is good also as a shape which has a simple part.

  In this case, the lower electrode and the wafer come into contact with each other in the vicinity of the wafer peripheral portion and the wafer central portion, and in the other portions, a space for reliably supplying He gas between the wafer and the lower electrode. Thus, it is possible to obtain higher temperature uniformity in the wafer surface.

  In the first embodiment, as the lower electrode 120a, for example, a gas discharge hole and a gas discharge port are formed on the surface of the lower electrode 120a, but the gas discharge port is not formed in the lower electrode. In this case, He gas is released at a predetermined flow rate from between the lower electrode and the wafer at the peripheral edge of the wafer.

  As mentioned above, although this invention has been illustrated using preferable embodiment of this invention, this invention should not be limited and limited to this embodiment. It is understood that the scope of the present invention should be construed only by the claims. It is understood that those skilled in the art can implement an equivalent range based on the description of the present invention and the common general technical knowledge from the description of specific preferred embodiments of the present invention. It is understood that the patent documents cited in the present specification should be incorporated by reference into the present specification in the same manner as the content itself is specifically described in the present specification.

  In the field of the wafer processing apparatus, the present invention provides a uniform sapphire substrate on a wafer stage such as a lower electrode and a gap between the lower electrode and a wafer mounting surface in the field of a wafer processing apparatus so that the temperature during processing of the sapphire substrate is uniform It is possible to provide a wafer processing apparatus that can be held in this manner.

DESCRIPTION OF SYMBOLS 100 Wafer clamp apparatus 101 Base member 110 Clamp part 111 Clamp arm 112 Lifting shaft 113 Actuator 120a Lower electrode 121a, 121b Gas ejection hole 123a Outer annular groove 123b Inner annular groove 124 Gas discharge port Wa Wafer

Claims (11)

A wafer processing apparatus having a chamber for processing a wafer and a stage provided in the chamber for mounting the wafer, and processing the wafer while maintaining its surface at an appropriate temperature. ,
A wafer holder for holding the wafer so that the wafer is fixed on the stage;
A heat exchanging unit for exchanging heat with the wafer so that the temperature of the wafer fixed on the stage is uniformly maintained;
The stage is a wafer processing apparatus in which the shape of the wafer mounting surface is made to match the warp characteristics of the sapphire wafer. The wafer processing apparatus according to claim 1,
The sapphire wafer constitutes a semiconductor light emitting device, and is a wafer processing apparatus. The wafer processing apparatus according to claim 1,
The stage is a convex curved surface on the wafer mounting surface,
The wafer holding portion has a peripheral portion of the wafer such that a central portion of the wafer is in contact with a vertex portion of the wafer placement portion of the stage, and a peripheral portion of the wafer is in contact with a peripheral portion of the wafer placement portion of the stage. A wafer processing apparatus for pressing and fixing a portion on the stage. The wafer processing apparatus according to claim 3,
The heat exchange part is
A wafer processing apparatus having a gas supply mechanism for supplying a gaseous heat exchange medium into a gap between a wafer mounting surface of the stage and a wafer pressed and fixed thereon. The wafer processing apparatus according to claim 4.
The wafer processing apparatus, wherein the gaseous medium is He gas. The wafer processing apparatus according to claim 1,
The wafer processing apparatus, wherein the wafer processing is a plasma etching process. The wafer processing apparatus according to claim 6.
The stage constitutes a lower electrode of a pair of upper and lower electrodes for applying high frequency power so that plasma is generated in the chamber,
A wafer processing apparatus, wherein the curvature of the convex surface of the lower electrode facing the wafer is a curvature at which the temperature of the wafer becomes uniform by heat exchange with the wafer by the gaseous medium. The wafer processing apparatus according to claim 7,
The curvature of the appropriately shaped lower electrode that keeps the wafer temperature uniform is such that the ratio P of the convex gap, which is the height at the center of the lower electrode, to the radius of the lower electrode is 0.001 ≦ P ≦ 0. A wafer processing apparatus set to be .008. The wafer processing apparatus according to claim 7,
The curvature of the appropriately shaped bottom electrode to keep the wafer temperature uniform is:
A wafer processing apparatus, wherein a ratio P of a convex gap, which is a height at a central portion of the lower electrode with respect to a radius of the lower electrode, is set to satisfy 0.001 ≦ P ≦ 0.004. The wafer processing apparatus according to claim 9, wherein
The curvature of the appropriately shaped bottom electrode to keep the wafer temperature uniform is:
A wafer processing apparatus, wherein a ratio P of the convex gap to a radius of the lower electrode is set to be 0.001 ≦ P ≦ 0.0021. The wafer processing apparatus according to claim 7,
The lower electrode is
At least a gas outlet for ejecting the gaseous medium and a gas outlet for discharging the ejected gas is formed on the surface, and the gas ejected from the gas outlet is circular. A wafer processing apparatus in which a plurality of annular grooves are formed concentrically so as to spread uniformly in the circumferential direction.

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