JP2016127032A - Support jig for silicon wafer heat treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support jig for silicon wafer heat treatment which can form an oxide film easily, and can suppress change over time of the silicon wafer holding state, by suppressing deformation of the support jig for silicon wafer heat treatment made of silicon.SOLUTION: A ring-shaped first jig 10 having a ring-shaped body 11, a ring-shaped protrusion 12, a first leg 13, and a second leg 14 are formed of silicon. The bottom face of the first leg 13 and the bottom face of the second leg 14 are formed to be located on the same surface. The ring-shaped protrusion 12 is arranged on the inside of the inner peripheral surface of a ring-shaped second jig 20, and the first leg 13 and second leg 14 are mounted on the plane part 20a of the second jig 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a support jig for heat treatment of a silicon wafer, and for example, a support jig for heat treatment of a silicon wafer used for supporting a silicon wafer when heat treatment such as RTP (Rapid Thermal Process) treatment or high temperature annealing is performed on the silicon wafer. It is about.

Conventionally, a support jig for silicon wafer heat treatment is used as a jig for holding a silicon wafer in annealing heat treatment or the like.
For example, when heat treatment is performed on a silicon wafer surface at a high temperature of 1100 to 1350 ° C. for a short time in rapid heating / cooling RTP treatment in a predetermined atmosphere and freezing excess atomic vacancies (Vacancy) inside, Alternatively, when performing heat treatment for eliminating crystal defects formed on the surface or bulk of the silicon wafer during crystal growth, a ring-shaped heat treatment support jig is used as a support jig for supporting the silicon wafer.

An example of the ring-shaped heat treatment support jig will be described using the heat treatment support jig disclosed in Patent Document 1 as an example.
As shown in FIG. 8, the heat treatment support jig 51 is formed in a so-called ring shape in which a space 51 a is formed at the center so as to support the outer peripheral portion of the silicon wafer W on the upper surface thereof. Further, the outer peripheral portion of the heat treatment support jig 51 is configured to be placed and held on a base 50 of an apparatus such as an RTP processing apparatus.
As the base material of the heat treatment support jig 51, silicon carbide or silicon is used from the viewpoints of strength, contamination, and the like.
In the case of the heat treatment support jig 51 made of silicon carbide, an oxide layer is generally formed on the surface thereof. This oxide film layer mainly suppresses welding between the heat treatment support jig 51 and the silicon wafer W and gives cushioning to the contact portion between the silicon wafer W and suppresses the occurrence of slip dislocation of the silicon wafer W. It is formed as a purpose.

Special table 2007-523466

By the way, when the support jig for heat treatment made of silicon carbide on which the oxide film layer is formed is used for high temperature heat treatment such as RTP treatment in a non-oxidizing atmosphere or long-time annealing in a non-oxidizing atmosphere, The oxide film is sublimated by an etching reaction with the silicon wafer (Si (solid) + SiO ₂ (solid) → 2SiO (gas)).
As a result, there was a technical problem that silicon carbide, which is the base material of the heat treatment support jig, was exposed, and slip dislocation occurred due to welding with the silicon wafer and a decrease in cushioning properties.

In order to solve this problem, when heat treatment in a non-oxidizing atmosphere is necessary, it is necessary to perform an oxidation treatment for re-forming an oxide film on the heat treatment support jig after the heat treatment.
However, since the oxidation rate of silicon carbide is very slow and the heat treatment for re-forming the oxide film takes a long time, the productivity of the support jig for heat treatment is lowered.
In particular, if an oxide film is to be re-formed while the support jig for heat treatment used in the RTP treatment is installed in the RTP treatment apparatus, it is necessary to repeat the heat treatment for a short time many times, thereby improving productivity. I couldn't. On the other hand, when the heat treatment support jig is removed from the RTP apparatus and oxidized in a resistance heating furnace, there is a problem that productivity is lowered and the chance of contamination is increased.

  On the other hand, when using a heat treatment support jig made of silicon with a high oxidation rate, the oxide film can be re-formed by heat treatment in an RTP apparatus, but deformation occurs over time in repeated high-temperature treatment. There has been a technical problem that slip dislocation occurs in the wafer due to a change in the holding state of the wafer.

In order to solve the above problems, the present inventors do not directly support a silicon wafer with the silicon carbide heat treatment support jig, but directly support the silicon wafer with a silicon heat treatment support jig. We examined on the premise of doing. Further, a heat treatment support jig in which the deformation with time of the silicon heat treatment support jig was suppressed and the slip dislocation of the silicon wafer was suppressed was examined.
As a result, by making the support jig for heat treatment made of silicon into a specific shape, an oxide film can be easily formed, and even when repeated high temperature treatment is performed, deformation over time is suppressed, The present invention contemplates a heat treatment support jig that can suppress slip dislocation caused by a change in the holding state.

  As described above, according to the present invention, an oxide film can be easily formed, and even when a high-temperature treatment is repeatedly performed, deformation with time is suppressed, and slip dislocation caused by a change in the holding state of the silicon wafer occurs. An object of the present invention is to provide a silicon wafer heat treatment support jig in which generation is suppressed.

  In order to achieve the above object, a silicon wafer heat treatment support jig according to the present invention includes a ring-shaped first jig that supports the back side of the outermost peripheral portion of a silicon wafer, and the first jig. A silicon wafer heat treatment support jig having a second jig on which a flat part to be held is formed, wherein the first jig has an upper surface part having an inclined surface that comes into contact with the silicon wafer and rises toward the outer periphery. A ring-shaped main body formed with a ring-shaped protrusion, and a ring-shaped protrusion formed by projecting downward from the lower surface of the inner peripheral portion of the ring-shaped main body. A first leg part formed on the lower surface of the ring-shaped main body part, and a second leg part formed between the first leg part and the ring-shaped projection part, The ring-shaped main body, the ring-shaped protrusion, The leg portion and the second leg portion are formed of silicon, and the bottom surface of the first leg portion and the bottom surface of the second leg portion are formed on the same plane, The protrusion is disposed inside the inner peripheral surface of the second jig, and the first leg and the second leg are placed on the flat surface of the second jig. It is a feature.

  As described above, the ring-shaped first jig that supports the back surface side of the outermost peripheral portion of the silicon wafer includes the ring-shaped main body portion, the ring-shaped protrusion, the first leg portion, and the second leg portion. Moreover, since it is made of silicon, an oxide film can be easily formed by heat treatment using an RTP apparatus or the like.

  Further, the ring-shaped first jig is not composed of only a ring-shaped main body on a flat plate, but a ring-shaped main body, a ring-shaped protrusion, a first leg, and a second leg. Since it is comprised from a part, rigidity improves and also a time-dependent deformation | transformation of a 1st jig | tool is suppressed also when it is repeatedly used for a high temperature process. As a result, the holding state of the silicon wafer is maintained, and the occurrence of slip dislocation due to the change in the holding state of the wafer can be suppressed.

Furthermore, the bottom surface of the first leg portion and the bottom surface of the second leg portion are formed on the same plane, and the ring-shaped protrusion is formed on the inner side of the ring-shaped second jig. The first leg portion and the second leg portion are placed on the flat surface portion of the second jig while being arranged on the inner peripheral surface.
That is, the horizontal direction of the ring-shaped first jig is regulated by the ring-shaped protrusion and the inner peripheral surface of the ring-shaped second jig. Further, the vertical direction of the ring-shaped first jig is regulated by the bottom surface of the first leg portion, the second leg portion, and the flat portion of the second jig.
As a result, the horizontal and vertical positions of the first jig are restricted, the inclination of the first jig is suppressed, and the deformation of the silicon wafer over time due to the non-uniformly acting weight of the silicon wafer. It is suppressed. As a result, the holding state of the wafer is maintained, and slip dislocation due to a change in the holding state of the wafer can be suppressed.

Here, it is desirable that the second leg portion is formed below a contact point between the silicon wafer and the slope of the upper surface portion.
Thus, since the second leg is formed below the contact point between the silicon wafer and the slope of the upper surface, the second leg can receive the weight of the silicon wafer.
As a result, deformation of the first jig is suppressed, the wafer holding state is more reliably maintained, and slip dislocation can be further suppressed.

In addition, a first recess formed between the ring-shaped protrusion and the second leg, and a second formed between the second leg and the first leg. It is desirable to provide a recess.
Moreover, it is desirable that the depth of the second recess is deeper than the depth of the first recess.
Thus, by forming the second recess deeper than the depth of the first recess, it is possible to further improve the heat uniformity of the upper surface portion of the ring-shaped main body.

It is desirable that the outer peripheral surface of the ring-shaped protrusion is positioned by the inner peripheral surface of the second jig.
In view of the practical processing accuracy of the ring-shaped first jig and the second jig, the diameter of the outer peripheral surface of the ring-shaped protrusion and the diameter of the inner peripheral surface of the second jig The difference is 0 mm or more and 0.5 mm or less.
When the difference between the diameter of the outer peripheral surface of the ring-shaped protrusion and the diameter of the inner peripheral surface of the second jig exceeds 0.5 mm, the ring-shaped first jig is moved to the second jig. It is easy to cause problems such as detachment from the tool, which is not preferable. Further, when the thickness exceeds 0.5 mm, the center position of the ring-shaped first jig varies within the apparatus, and the wafer is transferred from the center position of the ring-shaped first jig by the transfer robot. The wafer is placed and tilted with respect to the ring-shaped first jig. If the wafer is heat-treated in such a state where the wafer is tilted, slip is likely to occur, which is not desirable.

  The second jig is preferably formed of silicon carbide or silicon. The second jig may be silicon carbide because it is not in direct contact with the silicon wafer, and it is difficult for deformation to occur over time in repeated high-temperature processing.

  According to the present invention, an oxide film can be easily formed, and even when repeated high-temperature processing is performed, deformation with time is suppressed, and occurrence of slip dislocation due to a change in the holding state of the silicon wafer is suppressed. A silicon wafer heat treatment support jig can be obtained.

FIG. 1 is a cross-sectional view showing a first embodiment of a support jig for heat treatment of a silicon wafer according to the present invention. FIG. 2 is a partial cross-sectional view of the first jig used in FIG. FIG. 3 is a partial cross-sectional view showing a first modification of the first jig. FIG. 4 is a partial cross-sectional view showing a state in which a silicon wafer is placed on the first jig shown in FIG. FIG. 5 is a partial cross-sectional view showing a second modification of the first jig. FIG. 6 is a partial cross-sectional view showing an inclined state when the leg portion is not formed on the first jig. FIG. 7 is a diagram illustrating a slip evaluation result. FIG. 8 is a sectional view showing a conventional silicon wafer heat treatment support jig.

A first embodiment of a silicon wafer heat treatment support jig according to the present invention will be described with reference to FIGS.
As shown in FIG. 1, the silicon wafer heat treatment support jig 1 includes a ring-shaped first jig 10 that supports the back surface side of the outermost peripheral portion of the silicon wafer W, and the first jig 10. And a ring-shaped second jig 20 having a holding flat portion 20a.
The outermost peripheral portion means a range of 2 mm from the end portion of the outermost periphery of the wafer including the bevel portion toward the center of the wafer. Further, the second jig 20 may not necessarily have a ring shape as long as it is fixed in the apparatus and the position of the first jig 10 in the horizontal direction and the vertical direction is regulated. . For the same reason, one direction of the ring may be missing due to the convenience of the wafer transfer device.

As shown in FIG. 2, the first jig 10 includes a ring-shaped main body portion 11 having an upper surface portion 11 a having a slope that rises toward the outer periphery, and a lower portion from the inner peripheral portion of the ring-shaped main body portion 11. And a ring-shaped protrusion 12 that protrudes in the direction.
A silicon wafer W is placed on the slope of the upper surface portion 11 a of the ring-shaped main body portion 11. That is, a slope is formed in the portion of the upper surface portion 11a that contacts the silicon wafer W so as to hold the back surface side of the outermost peripheral portion of the silicon wafer.
It is sufficient that the inclined surface is formed at a position that holds the back surface side of the outermost peripheral portion of the silicon wafer. However, in consideration of an error in the mounting state of the wafer, the outer peripheral surface 12a of the ring-shaped protrusion 12 is provided. In addition, an inclined surface is formed so as to increase in height from the circular line P where the upper surface portion 11a intersects in the outer circumferential direction.

  Further, a first leg portion 13 that protrudes downward from the outer peripheral portion of the ring-shaped main body portion 11 is formed. Furthermore, a second leg 14 that protrudes downward from the ring-shaped main body 11 is formed between the first leg 13 and the ring-shaped protrusion 12. The second leg portion 14 is formed at a substantially intermediate position between the first leg portion 13 and the ring-shaped protrusion 12.

  Further, the bottom surface of the first leg 13 and the bottom surface of the second leg 14 are formed so as to be located on the same plane A as shown in FIG. In a state where the second leg portion 14 is placed on a horizontal plane, the slope of the upper surface portion 11a is formed to have a predetermined angle θ (for example, an angle of 45 degrees or less).

  A first ring-shaped recess 15 is formed between the ring-shaped protrusion 12 and the second leg 14. A second ring-shaped recess 16 is formed between the first leg 13 and the second leg 14. The depth t1 of the first ring-shaped recess 15 and the depth t2 of the second ring-shaped recess 16 are formed to the same depth.

A curved surface portion 17 a is formed at a boundary portion between the outer peripheral surface 12 a of the ring-shaped protrusion 12 and the bottom surface 15 a of the first ring-shaped recess 15. A curved surface portion 17b is formed at the boundary between the bottom surface 15a of the first ring-shaped recess 15 and the inner peripheral surface 14a of the second leg portion 14.
Further, a curved surface portion 17 c is formed at a boundary portion between the bottom surface 16 a of the second ring-shaped recess 16 and the outer peripheral surface 14 b of the second leg portion 14. A curved surface portion 17 d is formed at the boundary between the bottom surface 16 a of the second ring-shaped recess 16 and the inner peripheral surface 13 a of the first leg portion 13.
These curved surface portions 17a, 17b, 17c, and 17d are formed to avoid stress concentration. Thus, since the curved surface portions 17a, 17b, 17c, and 17d are formed, the deformation of the first jig 10 is further suppressed.

Also, as shown in FIG. 3, it is more preferable that the depth t2 of the second ring-shaped recess 16 is formed deeper than the depth t1 of the first ring-shaped recess 15 in consideration of the heat capacity. .
As described above, the slope of the upper surface portion 11a is formed to have a predetermined angle θ (for example, an angle of 45 degrees or less). Therefore, as shown in FIG. 2, when the depth t1 of the first ring-shaped recess 15 and the depth t2 of the second ring-shaped recess 16 are formed to the same depth, the ring-shaped Compared to the inner peripheral part side of the main body part 11, the outer peripheral part side is thicker. That is, the heat capacity on the outer peripheral portion side of the ring-shaped main body portion 11 is increased, and there is a possibility that the temperature is not uniform between the inner peripheral portion side and the outer peripheral portion side of the ring-shaped main body portion 11.

On the other hand, as shown in FIG. 3, the ring-shaped main body portion is formed by forming the depth t2 of the second ring-shaped recess 16 deeper than the depth t1 of the first ring-shaped recess 15. The thickness of the inner peripheral side of 11 and the thickness of the outer peripheral side can be made substantially the same, and the heat uniformity of the upper surface part 11a of the ring-shaped main body part 11 can be further improved.
When the depth t1 of the first ring-shaped recess 15 and the depth t2 of the second ring-shaped recess 16 are different in the radial direction, the average of the depth t2 of the second ring-shaped recess 16 is the same. The value should just be formed larger than the average value of the said 1st ring-shaped recessed part 15 depth t1.

Further, as shown in FIG. 4, when the silicon wafer W is placed on the upper surface portion 11a of the ring-shaped main body portion 11, the contact point B between the silicon wafer W and the upper surface portion 11a of the ring-shaped main body portion 11 is In some cases, the contact point B is located above the second ring-shaped recess 16 in FIG. 4 or above the second ring-shaped recess 16. Shows where it is located).
Since the load of the silicon wafer W acts on the contact point B, when the contact point B is located above the first ring-shaped recess 15 or above the second ring-shaped recess 16, There is a risk that the upper surface portion 11a of the ring-shaped main body portion 11 is deformed.

On the other hand, as shown in FIG. 5, when the second leg portion 14 is formed below the contact point B between the silicon wafer W and the upper surface portion 11 a of the ring-shaped main body portion 11, the silicon wafer W Therefore, the deformation of the first jig 10 is further suppressed, and slip dislocation due to the change of the holding state with the silicon wafer W can be suppressed.
Therefore, it is preferable that the second leg portion 14 is formed below a contact point B between the silicon wafer W and the upper surface portion 11 a of the ring-shaped main body portion 11.

In addition, as shown in FIG. 1, the second jig 20 has a ring-like shape that holds the held portion 20 b that is placed on an apparatus base 21 such as an RTP processing apparatus, and the first jig 10. And a flat portion 20a.
Then, the ring-shaped protrusion 12 of the first jig 10 enters the space C formed in the inner peripheral part of the second jig 20 (into the inner peripheral part of the second jig 20). The ring-shaped first jig 10 is positioned by the ring-shaped protrusion 12. Further, the first leg portion 13 and the second leg portion 14 are placed on the flat surface portion 20 a of the second jig 20.
As a result, the horizontal direction of the ring-shaped first jig 10 is regulated by the inner peripheral surface of the second jig 20, and the vertical direction is defined by the ring-shaped flat portion 20a of the second jig 20. Be regulated. Therefore, the ring-shaped first jig 10 can be placed with high accuracy with respect to the second jig 20, the inclination of the first jig 10 is suppressed, and the weight of the silicon wafer is not reduced. Sequential deformation due to uniform action is suppressed, and slip dislocation caused by a change in the holding state of the wafer can be suppressed.

  By the way, as shown in FIG. 6, the boundary between the outer peripheral surface 12a of the ring-shaped protrusion 12 and the bottom surface 11b of the ring-shaped main body 11 does not have a completely acute right angle for convenience of processing accuracy. The curved surface portion 18 is always formed. For this reason, as shown in FIG. 6A, when the first leg 13 and the second leg 14 are not formed, the outer peripheral surface 12a of the ring-shaped protrusion 12 and the second jig It mounts so that the inner peripheral surface of 20 may engage.

However, the state shown in FIG. 6 (a) is an unstable state, and as shown in FIG. 6 (b), the outer peripheral side of the ring-shaped main body portion 11 is lifted and inclined, or also in FIG. 6 (c). As shown, the inner peripheral side of the ring-shaped main body 11 is lifted and inclines. The states shown in FIGS. 6B and 6C occur in one first jig 10.
That is, a gap D (ring-shaped protrusion 12 for allowing the ring-shaped protrusion 12 to enter between the outer peripheral surface 12 a of the ring-shaped protrusion 12 and the inner peripheral surface 20 c of the second jig 20. The outer diameter of the second jig 20 and the diameter of the inner peripheral surface of the second jig 20), when the ring-shaped protrusion 12 enters the inner space C of the ring-shaped second jig 20, Instead of the state shown in FIG. 6A, the state shown in FIGS. 6B and 6C is obtained.

When the silicon wafer W is placed on the tilted first jig 10, the contact between the silicon wafer W and the first jig 10 becomes uneven on the circumference of the silicon wafer W. If heat treatment is performed in such a state, adverse effects such as occurrence of slip dislocation in the silicon wafer W occur.
Further, when the silicon wafer W is placed on the tilted first jig 10, the weight of the silicon wafer W acts on a part of the first jig 10 to deform the first jig 10. The harmful effect of promoting will arise.

Therefore, the difference between the diameter (outer diameter) of the outer peripheral surface 12a of the ring-shaped protrusion 12 and the diameter of the inner peripheral surface 20c of the ring-shaped second jig 20 is formed to be 0.5 mm or less. Yes.
In other words, the distance dimension (gap D) between the outer peripheral surface 12a of the ring-shaped protrusion 12 and the inner peripheral surface 20c of the ring-shaped second jig 20 is formed to be 0.25 mm or less.
The difference between the diameter of the outer peripheral surface (contact surface with the second jig) 12a of the ring-shaped protrusion 12 and the diameter of the inner peripheral surface of the ring-shaped first jig 10 is 0.5 mm. In the case of exceeding the first jig 10, the first jig 10 cannot be accurately positioned with respect to the second jig 20, and the ring-shaped main body portion 11 (upper surface portion 11a) is inclined, It is not preferable.

On the other hand, when the difference between the diameter of the outer peripheral surface 12a of the ring-shaped protrusion 12 and the diameter of the inner peripheral surface 20c of the ring-shaped second jig 20 is 0 mm, the ring-shaped second This is not preferable because it is difficult to allow the ring-shaped protrusion 12 to enter between the inner peripheral surface 20c of the jig 20.
However, by design, even if the difference between the diameter of the outer peripheral surface 12a of the ring-shaped protrusion 12 and the diameter of the inner peripheral surface 20c of the ring-shaped second jig 20 is 0 mm, In some cases, the ring-shaped protrusion 12 can be fitted into the ring-shaped second jig 20.
Therefore, even if the difference between the diameter (outer diameter) of the outer peripheral surface 12a of the ring-shaped protrusion 12 and the diameter of the inner peripheral surface 20c of the ring-shaped second jig 20 is 0 mm or more. good.

The first jig 10 (ring-shaped main body 11, ring-shaped protrusion 12, first leg 13, and second leg 14) is formed of single crystal or polycrystalline silicon.
A ring-shaped protrusion 12 is formed on the inner peripheral side of the ring-shaped main body 11, and the first leg 13 and the second leg 14 are formed in a rib shape in the circumferential direction of the ring-shaped main body 11. Therefore, the rigidity of the first jig 10 can be improved and deformation can be further suppressed.
As a result, even when the first jig 10 is formed of single crystal or polycrystalline silicon and repeatedly used for high temperature processing, the deformation of the first jig 10 is suppressed and the wafer W is held. Is maintained, and slip dislocation caused by a change in the holding state of the wafer W can be suppressed.
The second jig 20 is made of silicon carbide or single crystal or polycrystalline silicon. The second jig is more preferably silicon carbide because it is not in direct contact with the silicon wafer, and moreover it is difficult for deformation to occur over time in repeated high-temperature processing.

Thus, the silicon wafer W is not directly placed on the ring-shaped second jig 20 formed of silicon carbide, and the first jig 10 formed of single crystal or polycrystalline silicon is used. A silicon wafer W is placed on top.
Therefore, as in the conventional case, it is possible to suppress welding with the silicon wafer due to exposure of silicon carbide as a base material, and it is possible to suppress the occurrence of slip dislocation due to a decrease in cushioning properties.
Since the ring-shaped first jig 10 is formed of single crystal or polycrystalline silicon as described above, the oxidation rate is high, and the oxide film of the oxide film is formed by heat treatment in an RTP apparatus or the like. Re-formation can be performed easily. Further, since the ring-shaped first jig 10 is formed in a specific shape, deformation over time can be suppressed, and slip dislocation caused by a change in the holding state of the silicon wafer can be suppressed.

Using the first jig of the present invention shown in FIG. 1 (FIG. 3) made of silicon, a mirror-polished φ300 mm silicon wafer was heat-treated with an RTP apparatus.
As a first jig, the thickness dimension from the upper surface portion of the ring-shaped main body portion to the bottom surface of the ring-shaped projection portion (center of the bottom surface in the radial direction) is 0.9 mm, and the first jig from the upper surface portion of the ring-shaped main body portion is A material having a thickness of 0.7 mm up to the bottom of the leg (the center of the bottom in the radial direction) and a slope angle of 6 degrees was used. Furthermore, the device in the production was devised so that the second leg bottom surface is flush with the first leg bottom surface.
Further, the diameter of the outer peripheral surface of the ring-shaped protrusion is 295.2 mm, the diameter of the inner peripheral surface of the second jig is 295.2 mm, and the difference is cut out from the Si single crystal as 0.0 mm. Only what was produced and washed and then fitted to the second jig after cleaning was used in the heat treatment test described below. The back side of the silicon wafer bevel was placed on the top surface of the ring-shaped main body above the second leg.
The heat treatment conditions were as follows: heat treatment was performed at a maximum temperature of 1350 ° C. × 10 sec in an argon atmosphere, and then heat treatment was performed at a maximum temperature of 1300 ° C. × 15 sec in an oxygen atmosphere without removing the wafer from the RTP apparatus. . This heat treatment was performed a plurality of times, and slip evaluation was performed on the number of processed sheets.

Slip evaluation was performed by measuring an evaluation wafer processed with one ring-shaped first jig using PIRTepra's SIRD (Scanning Infrared Depolarization). SIRD is characterized in that the stress field inside the crystal is measured as the amount of polarization displacement of transmitted polarized infrared light, and a map of stress is drawn. A laser diode with a wavelength of 1.3 μm is used as the light source, and the light is linearly polarized and then transmitted through the wafer. The transmitted light enters the polarization detector, and the amount of polarization displacement from the initial polarization state is measured.
The ratio (strain area ratio) of the area where the strain stress increases due to the slip with respect to the area of the entire silicon wafer is calculated from the map of the stress. That is, the larger the strain area ratio, the worse the slip quality, and the smaller the strain area ratio, the better the slip quality.
In one ring-shaped first jig, after processing a predetermined number of wafers, processing the evaluation wafer immediately after correcting the output value of the radiation thermometer that monitors the temperature in the furnace Was repeated several times. By doing in this way, since the influence of the temperature distribution fluctuation in the evaluation wafer surface with respect to a slip can be excluded, only the characteristic of the ring-shaped first jig itself can be extracted.
The slip evaluation result of the evaluation wafer obtained as described above is shown in FIG.

As a comparative example, the first jig in which the first leg portion and the second leg portion are not formed (FIG. 6) was used, and the others were compared in the same procedure as in the first embodiment.
Specifically, as the first jig, the thickness dimension from the upper surface portion of the ring-shaped main body portion to the bottom surface of the ring-shaped projection portion is 1.0 mm, and the thickness dimension of the outer peripheral portion of the ring-shaped main body portion is 0.5 mm. In addition, those having a slope angle of 6 degrees were used. In addition, what is thinner than Example 1 is based on the result of optimizing the slip.
Further, the diameter of the outer peripheral surface of the ring-shaped protrusion was 295.3 mm, the diameter of the inner peripheral surface of the second jig was 295.2 mm, and the difference was minus 0.1 mm. This is based on the result of optimizing the slip as well as the thickness.
The slip evaluation results are shown in FIG. Note that most of the first jig is mounted on the second jig even though the diameter of the outer peripheral surface of the ring-shaped protrusion is larger than the diameter of the inner peripheral surface of the second jig. Was possible. This is also because the shape of FIG. 6 is insufficient in rigidity, so that it can be easily deformed and mounted.

  As can be seen from FIG. 7, in the comparative example, the variation is increased by increasing the number of processed sheets, and the strain area ratio is deteriorated. There was no deterioration of slip quality in the continuous treatment. In the comparative example, as shown in FIG. 7, since the strain area ratio increased rapidly, the evaluation with the subsequent strain area ratio was not performed.

1 Support jig for silicon wafer heat treatment.
DESCRIPTION OF SYMBOLS 10 1st jig | tool 11 Ring-shaped main-body part 11a Upper surface part 12 Ring-shaped projection part 13 1st leg part 14 2nd leg part 15 1st recessed part 16 2nd recessed part 17a Curved part 17b Curved part 17c Curved part 17d Curved surface portion 20 Second jig 20a Planar portion 20c Inner circumferential surface A Coplanar surface B Contact point C Inner circumferential space portion of second jig D Gap

Claims (6)

A silicon wafer heat treatment support jig having a ring-shaped first jig for supporting the back surface side of the outermost peripheral part of the silicon wafer and a second jig on which a flat part for holding the first jig is formed. Because
The first jig is
A ring-shaped main body formed with an upper surface portion having a slope that rises toward the outer periphery, which comes into contact with the silicon wafer;
A ring-shaped protrusion formed to protrude downward from the lower surface of the inner peripheral portion of the ring-shaped main body,
A first leg formed to project downward from the lower surface of the outer periphery of the ring-shaped main body;
A second leg formed between the first leg and the ring-shaped protrusion on the lower surface of the ring-shaped main body;
The ring-shaped main body, the ring-shaped protrusion, the first leg, and the second leg are formed of silicon, and the bottom surface of the first leg and the bottom of the second leg are the same. Formed on the surface,
The ring-shaped protrusion is disposed inside the inner peripheral surface of the second jig, and the first leg and the second leg are placed on the flat surface of the second jig. A support jig for heat treatment of a silicon wafer.   2. The ring-shaped silicon wafer heat treatment support jig according to claim 1, wherein the second leg portion is formed below a contact point between the silicon wafer and the slope of the upper surface portion. A first recess formed between the ring-shaped protrusion and the second leg,
The ring-shaped silicon wafer heat treatment support according to claim 1 or 2, further comprising a second recess formed between the second leg and the first leg. Ingredients.   The ring-shaped silicon wafer heat treatment support jig according to claim 3, wherein the depth of the second recess is deeper than the depth of the first recess.   5. The silicon wafer heat treatment support jig according to claim 1, wherein an outer peripheral surface of the ring-shaped protrusion is positioned by an inner peripheral surface of the second jig. 6. .   6. The silicon wafer heat treatment support jig according to claim 1, wherein the second jig is made of silicon carbide or silicon.

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