Wafer fixture structure and processing equipment causing high temperature creep deformation

Abstract

The present invention provides a wafer fixture structure and a processing apparatus for inducing high-temperature creep deformation. The wafer fixture structure mainly includes two separable fixtures. The first fixture has a first inclined surface, and the second fixture has another second inclined surface. The first inclined surface and the second inclined surface are parallel to each other and are simultaneously inclined to the direction of an external force application. When the first fixture and the second fixture are brought into contact with each other and the wafer is clamped between the first inclined surface and the second inclined surface, by applying an external force, the chip will be subjected to a shear stress component along the chip surface. If the external force is operated at a high temperature, high-temperature creep will occur in this wafer. This inclined structure of the wafer fixture and the auxiliary processing apparatus precisely illustrate that by using the inclined design of the fixture, high-temperature creep deformation can be easily activated and developed in the wafer, thereby improving the geometry of the wafer.

Description

Technical Field

[0001] The present invention relates to a wafer fixture structure and a processing apparatus, and more particularly to a wafer fixture with an inclined design structure and a wafer high-temperature processing apparatus that can easily activate and develop high-temperature creep deformation. Background Art

[0002] In the semiconductor industry, the materials of wafers include, for example, silicon (Si), gallium arsenide (GaAs), indium phosphide (InP), indium antimonide (InSb), gallium nitride (GaN), silicon carbide (SiC), or zinc selenide (ZnSe). Generally, the method of manufacturing a wafer includes first forming an ingot and then slicing the ingot to obtain a wafer. The ingot is manufactured, for example, in a high-temperature environment. Currently, the methods for growing an ingot include the Czochralski process, Physical Vapor Transport (PVT), High Temperature Chemical Vapor Deposition (HT-CVD), and Liquid Phase Epitaxy (LPE).

[0003] The seed is placed in a high-temperature furnace. The seed contacts a gaseous or liquid raw material, and a semiconductor material is formed on the surface of the seed until an ingot with an expected size is obtained. The ingot may have different crystal structures depending on the manufacturing method and raw materials. For example, the ingot of silicon carbide includes 3C-silicon carbide, 4H-silicon carbide, 6H-silicon carbide, etc. 3C-silicon carbide belongs to the cubic crystal system, while 4H-silicon carbide and 6H-silicon carbide belong to the hexagonal crystal system.

[0004] The ingot grows in a high-temperature environment of several hundred degrees Celsius to several thousand degrees Celsius. During the growth process of the ingot, the upper end of the ingot, i.e., the end adjacent to the seed, is called the seed end. The lower end of the ingot, which is also the end far from the seed, is called the dome end. There may be a temperature difference of several tens to several hundred degrees Celsius between the seed end and the dome end due to their different positions. In this case, residual stress may occur inside the ingot due to the temperature difference and the inability to perform stress re-distribution and strain release in time. If the ingot is silicon carbide, the seed end is the silicon face, and the dome end is the carbon face. The silicon face of the ingot can develop residual compressive stress, and the carbon face of the ingot can exhibit residual tensile stress.

[0005] After the ingot growth is completed, the ingot is cooled to room temperature by furnace cooling or other methods. When the ingot is cooled to below the plastic-elastic transition temperature, the shrinkage deformation caused by the cooling is gradually unable to be released by the timely plastic deformation of the crystal (such as dislocation generation, slip and / or combination). For example, dislocation can slip along a specific slip direction on a corresponding slip plane and disappear on the surface of the crystal. If the ingot only considers elastic deformation and ignores the characteristics of slow plastic deformation (for example: high temperature creep), the thermal shrinkage of the ingot roughly conforms to the following formula:

[0006] ε=kΔΤ

[0007] In the above formula, ε is strain, k is the coefficient of thermal expansion, and ΔT is the temperature difference. When cooling the ingot, if the temperature of the seed end is different from the temperature of the dome end, the seed end and the dome end will start to cool down from different temperatures, causing the degree of thermal contraction of the seed end to be different from that of the dome end. For example, the seed end may be cooled from 1800 degrees Celsius to 20 degrees from room temperature, and the dome end may be cooled from 1900 degrees Celsius to 20 degrees. This situation results in different temperature gradients at both ends of the ingot, and the shrinkage sequence is not synchronized in time, resulting in residual compressive stress and tensile stress. Simply put, because the ΔT of the seed end is different from the ΔT of the dome end, the ε of the seed end is different from the ε of the dome end.

[0008] After the ingot cools down, a cutter is used to remove the poorly shaped ends of the ingot, and then the ingot is ground to the desired size (e.g., 3 inches to 12 inches) using a grinding wheel. In some processes, a flat edge or a V-shaped groove is ground on the edge of the ingot. This flat edge or V-shaped groove is suitable for marking the crystal orientation of the ingot or for fixing the ingot.

[0009] The ingot is then sliced ​​to obtain multiple wafers. For example, the method of slicing the ingot includes cutting with a knife or steel wire in combination with abrasive particles (such as diamond particles). In some cases, the interior of the wafer has residual compressive stress and tensile stress like the ingot. In some processes, the edges and corners of the wafer are ground into rounded corners to prevent the edges and corners of the wafer from breaking due to collision.

[0010] Next, a grinding and polishing process is performed on the wafer to improve the surface quality of the wafer. Methods for performing the grinding and polishing process on the wafer include, for example, a physical grinding process and a chemical mechanical polishing process. The physical grinding process, for example, grinds the wafer surface with a polishing pad in cooperation with a grinding fluid containing diamond particles or other harder particles. The physical grinding process mainly processes the wafer surface with mechanical force. The chemical mechanical polishing process uses a corrosive grinding fluid and abrasive in cooperation with a polishing pad to grind the wafer surface. The corrosive grinding fluid in the chemical mechanical polishing process can chemically react with the wafer surface, converting the uneven parts of the wafer surface into materials with lower hardness, thereby enabling the abrasive to more easily remove the uneven parts of the wafer surface.

[0011] After the grinding and polishing process, the thickness of the wafer is reduced (for example, reduced by hundreds of micrometers). The residual tensile stress and compressive stress inside the wafer will be partially released (stress relaxation) and the force distribution will be reorganized (stress re-distribution) due to the reduction in the wafer thickness, which may lead to geometric warping such as bow and / or warp of the wafer.

[0012] Therefore, how to improve the above geometric warping after the silicon carbide wafer is cut or ground is an important issue in the growth of physical vapor transport (PVT) crystals and its semiconductor material manufacturing processes. Summary of the Invention

[0013] The present invention is directed to an inclined design structure of a wafer fixture and a wafer processing device, which can effectively improve the geometric warping of the wafer through a low-temperature annealing process.

[0014] According to an embodiment of the present invention, the wafer fixture structure includes a first fixture and a second fixture. The first fixture has a first inclined surface, and the second fixture has a second inclined surface. The inclined surfaces are parallel to each other and are simultaneously inclined with respect to the direction of the externally applied force. When the first fixture and the second fixture are brought into contact with each other and the wafer is clamped between the first inclined surface and the second inclined surface, by applying an external force, the chip will be subjected to a shear stress component along the chip surface. If the external force is applied at a high temperature, high-temperature creep will occur in the wafer.

[0015] According to an embodiment of the present invention, the wafer fixture structure includes a first fixture and a second fixture. The first fixture has a first inclined surface. The second fixture has a second inclined surface, wherein the first fixture and the second fixture are brought into contact with each other such that the first inclined surface faces the second inclined surface and a clamping space is formed between the first inclined surface and the second inclined surface. The peripheral part of the first fixture and the peripheral part of the second fixture surround the clamping space, and there is a gap between the peripheral part of the first fixture and the peripheral part of the second fixture.

[0016] In an embodiment according to the present invention, when the first jig and the second jig are brought into contact with each other, the first jig and the second jig together form a cylindrical structure.

[0017] In an embodiment according to the present invention, the wafer jig structure further includes at least one positioning member, wherein at least one first groove is provided on the outer peripheral surface of the first jig, at least one second groove is provided on the outer peripheral surface of the second jig, and the at least one positioning member is adapted to be partially embedded in the at least one first groove and partially embedded in the at least one second groove.

[0018] In an embodiment according to the present invention, the wafer jig structure further includes a force application assembly, wherein the force application assembly is adapted to be connected to the first jig and the second jig and apply an external force to the first jig and the second jig.

[0019] In an embodiment according to the present invention, the wafer jig structure further includes two sacrificial layers, and the two sacrificial layers are adapted to be respectively disposed on the first inclined surface and the second inclined surface to contact the wafer.

[0020] In an embodiment according to the present invention, each sacrificial layer may be a silicon carbide spacer or a silicon carbide CVD coating.

[0021] In an embodiment according to the present invention, the first jig has a bottom surface relative to the first inclined surface, the second jig has a top surface relative to the second inclined surface, and both the bottom surface and the top surface are horizontal surfaces.

[0022] According to an embodiment of the present invention, the wafer jig structure includes a first jig and a second jig. The first jig has opposite first and second sides. The thickness of the first side in the pressing direction is greater than the thickness of the second side in the pressing direction. The second jig has opposite third and fourth sides. The thickness of the third side in the pressing direction is greater than the thickness of the fourth side in the pressing direction. When the first jig and the second jig are brought into contact with each other such that the first side corresponds to the fourth side and the second side corresponds to the third side, the wafer is clamped between the first jig and the second jig, and the first jig and the second jig are adapted to press the wafer by an external force applied in the pressing direction.

[0023] In an embodiment according to the present invention, when the wafer is clamped between the first jig and the first jig, the first jig and the second jig together form a cylindrical structure, and the pressing direction is parallel to the axial direction of the cylindrical structure.

[0024] In an embodiment according to the present invention, the first jig has a first inclined surface, the second jig has a second inclined surface, the wafer is adapted to be clamped between the first inclined surface and the second inclined surface, and the inclination angles of the first inclined surface and the second inclined surface relative to the pressing direction are between 0 and 45 degrees, between 15 and 35 degrees, between 20 and 30 degrees, or between 22 and 28 degrees, or is 25 degrees.

[0025] In an embodiment according to the present invention, the wafer fixture structure further includes at least one positioning member, wherein at least one first groove is formed on the outer peripheral surface of the first fixture, at least one second groove is formed on the outer peripheral surface of the second fixture, and the at least one positioning member is adapted to be partially embedded in the at least one first groove and partially embedded in the at least one second groove.

[0026] In an embodiment according to the present invention, the wafer fixture structure further includes a force application assembly, wherein the force application assembly is adapted to be connected to the first fixture and the second fixture and apply an external force to the first fixture and the second fixture.

[0027] In an embodiment according to the present invention, the wafer fixture structure further includes two sacrificial layers, and the two sacrificial layers are adapted to be respectively disposed on the first inclined surface and the second inclined surface to contact the wafer.

[0028] In an embodiment according to the present invention, each sacrificial layer is a silicon carbide spacer or a silicon carbide CVD coating.

[0029] In an embodiment according to the present invention, the first fixture has a bottom surface relative to the first inclined surface, the second fixture has a top surface relative to the second inclined surface, and both the bottom surface and the top surface are horizontal surfaces perpendicular to the pressing direction.

[0030] According to an embodiment of the present invention, the wafer processing apparatus includes the above-mentioned wafer fixture structure and a heat source. The heat source is adapted to heat the wafer sandwiched between the first inclined surface and the second inclined surface.

[0031] Based on the above, in the wafer fixture structure of the present invention, the first fixture and the second fixture clamp the wafer through the first inclined surface and the second inclined surface respectively, so that the wafer is annealed and subjected to high-temperature creep treatment in an inclined state, and part of the stress can be appropriately released. Thus, the wafer fixture structure of the present invention can effectively improve the geometric warpage of the wafer through annealing treatment. Description of the Drawings

[0032] Figure 1 is a top view schematic diagram of a wafer processing apparatus according to an embodiment of the present invention;

[0033] Figure 2 is Figure 1 a three-dimensional view of the wafer fixture structure of;

[0034] Figure 3 is Figure 2 an exploded view of the wafer fixture structure of;

[0035] Figure 4 is Figure 2 a cross-sectional schematic diagram of the first fixture and the second fixture clamping the wafer of;

[0036] Figure 5 is Figure 4 a partial enlarged view of the first fixture, the second fixture and the wafer of;

[0037] Figure 6 shows that Figure 4 the first inclined plane and the second inclined plane have positive bow values;

[0038] Figure 7 is a partial enlarged view of the first jig, the second jig and the wafer according to another embodiment of the present invention. Detailed Description of the Invention

[0039] Reference will now be made in detail to exemplary embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Whenever possible, the same reference numerals will be used in the drawings and the description to refer to the same or like parts.

[0040] Figure 1 is a top view schematic diagram of a wafer processing apparatus according to an embodiment of the present invention. Please refer to Figure 1 , the wafer processing apparatus 10 of this embodiment includes a wafer jig structure 100 and a heat source 12. The wafer jig structure 100 is used to hold the wafer that has been cut or ground, and the heat source 12 is used to heat the wafer held by the wafer jig structure 100 to perform annealing and creep processing on the wafer. In Figure 1 , only a part of the heat source 12 is shown, and the heat source 12 is shown as being arranged in a manner surrounding the wafer jig structure 100. However, this is only for illustration, and the heat source 12 can be any suitable form of heating device, for example, the heat provided is conducted to the wafer through the wafer jig structure 100, and it can be resistance heating or induction heating. The present invention does not limit this.

[0041] Figure 2 is Figure 1 a perspective view of the wafer jig structure of Figure 3 is Figure 2 an exploded view of the wafer jig structure of Figure 4 is Figure 2 a cross-sectional schematic view of the first jig and the second jig clamping the wafer of Figures 2 to 4, the wafer jig structure 100 of this embodiment includes a base 105, a first jig 110, and a second jig 120. The materials of the first jig 110 and the second jig 120 are, for example, graphite. In other embodiments, the materials of the first jig 110 and the second jig 120 can be carbides, such as materials like TiC, WC, SiC, MoC, BC, or high-temperature anti-carbonization metal materials or metal compounds like W, Mo. Moreover, the materials of the first jig 110 and the second jig 120 can be selected as different or the same materials according to the design or requirements of the process, and the present invention does not limit this. The base 105 is used to carry the first jig 110 and the second jig 120. The first jig 110 has opposite first side S1 and second side S2 and has a first inclined surface 110a, and the second jig 120 has opposite third side S3 and fourth side S4 and has a second inclined surface 120a. The thickness of the first side S1 in the pressing directions D1, D2 is greater than the thickness of the second side S2 in the pressing directions D1, D2, thereby forming the first inclined surface 110a, and the thickness of the third side S3 in the pressing directions D1, D2 is greater than the thickness of the fourth side S4 in the pressing directions D1, D2, thereby forming the second inclined surface 120a. When the first jig 110 and the second jig 120 are abutted against each other as shown in Figure 2 and Figure 4 such that the first side S1 corresponds to the fourth side S4 and the second side S2 corresponds to the third side S3, the first inclined surface 110a faces the second inclined surface 120a, and a clamping space CS is formed between the first inclined surface 110a and the second inclined surface 120a. The wafer W is clamped between the first inclined surface 110a and the second inclined surface 120a and is located within the clamping space CS. The first jig 110 and the second jig 120 jointly form a cylindrical structure, for example, and the first inclined surface 110a and the second inclined surface 120a are parallel to each other and inclined to the pressing directions D1, D2 along the inclined direction D3. The pressing directions D1, D2 are parallel to the axial direction A of the cylindrical structure (marked in Figure 2 ). Figure 1 The heat source 12 shown is adapted to heat the wafer W clamped between the first inclined surface 110a and the second inclined surface 120a. The first jig 110 and the second jig 120 are adapted to apply the pressure required for annealing treatment to the wafer W by an external force applied along the pressing directions D1, D2. The wafer jig structure 100 of this embodiment can apply and adjust the external force to the first jig 110 and the second jig 120 through any suitable force-applying component or heavy object, and the present invention does not limit this.

[0042] Figure 5 is Figure 4 a partial enlarged view of the first jig, the second jig, and the wafer. Please refer to Figure 5When the first jig 110 and the second jig 120 clamp the wafer W, the peripheral portion 110d of the first jig 110 and the peripheral portion 120d of the second jig 120 surround the clamping space CS and the wafer W therein, and there is a gap G between the peripheral portion 110d of the first jig 110 and the peripheral portion 120d of the second jig 120 without contacting each other, so as to prevent the first jig 110 and the second jig 120 from generating acting forces on each other in the pressing directions D1 and D2 and affecting the pressing on the wafer W. The gap G is greater than 0, for example, about 200 microns.

[0043] As described above, the first jig 110 and the second jig 120 of this embodiment clamp the wafer W through the first inclined surface 110a and the second inclined surface 120a respectively, so that the wafer W is annealed in an inclined state, and the geometric warpage of the wafer W is effectively improved through annealing and creep treatment. Specifically, when tensile stress and compressive stress remain in the wafer W, after the wafer W is ground and polished to become thinner, the rigidity of the wafer becomes smaller, and the influence degree of the stress on its geometric shape gradually becomes larger, which will cause more obvious geometric warpage such as bow and / or warp. Among them, the tensile stress and the compressive stress have a tendency to change the bow value of the wafer W to a negative value, for example. To improve this geometric defect, in this embodiment, in a graphite heating reduction furnace with a temperature of about 1200 to 1600 degrees Celsius and a pressure of about 100 to 1000 Mpa, an external pressure is applied to the wafer W that has been cut and not yet ground and polished or has been ground but not polished through the first jig 110 and the second jig 120. The wafer W is in an inclined state due to the setting of the first inclined surface 110a of the first jig 110 and the second inclined surface 120a of the second jig 120, that is, the normal line of the carbon surface of the wafer W is inclined and extends along the <11-20> direction. Thus, as long as the external compressive force applied by the first jig 110 and the second jig 120 to the wafer W exceeds a certain critical value, the shear force will drive the existing dislocations to slide on the plane parallel to {0001} of the wafer W along the <11-20> direction, thereby partially eliminating and reorganizing the residual stress inside the wafer W. The internal dislocations of the silicon carbide crystal can slide on various combinations of slip planes and slip directions. However, among them, the {0001} crystal plane can be driven to slide by the smallest shear force along the <11-20> direction, so as to achieve the annealing creep effect. Among them, the smaller the inclination angle of the wafer W, the greater the required external pressure. The sliding and climbing of the dislocations release part of the residual stress in the wafer W. In this embodiment, for example, the process of applying the external compressive force is performed at a predetermined temperature (such as 1200 to 1600 degrees Celsius as described above) for 1 to 3 hours, and then the furnace power is turned off. The bow value of the wafer W is improved in this way, and even becomes a positive bow value, which varies according to the surface curvature design of 11a and 11b. Among them, the first inclined surface 110a and the second inclined surface 120a have a predetermined positive bow value, for example, and will not prevent the bow value of the wafer W clamped therebetween from becoming positive. For example, Figure 6, in other embodiments, the first inclined surface 110a and the second inclined surface 120a may also have a predetermined negative bow value, or have the same or different predetermined bow values by changing the surface curvature of 11a and 11b according to the process design or requirements. Then, after the wafer W is thinned by further grinding and polishing (such as by chemical mechanical polishing, CMP), the influence of the stress on the wafer W gradually increases, causing its bow value to change to a negative value. And since the wafer W has a positive bow value through heat treatment as described above before grinding and polishing, its bow value changes to a normal value between -25 microns and 25 microns, or even a normal value between -15 microns and 15 microns due to the influence of the stress after grinding and polishing.

[0044] In this embodiment, the inclination angles of the first inclined surface 110a and the second inclined surface 120a relative to the pressing directions D1 and D2 may be between 0 and 45 degrees, preferably between 15 and 35 degrees, more preferably between 20 and 30 degrees, still more preferably between 22 and 28 degrees, and most preferably 25 degrees. By designing the inclination angles of the first inclined surface 110a and the second inclined surface 120a as the above angles, their inclination directions can generally correspond to the aforementioned <11-20> direction, so that the dislocations slide along the <11-20> direction on the carbon surface of the wafer W to partially eliminate the residual stress of the wafer W as described above.

[0045] In this embodiment, the first jig 110 has a bottom surface 110c relative to the first inclined surface 110a, and the second jig 120 has a top surface 120c relative to the second inclined surface 120a. Both the bottom surface 110c and the top surface 120c are horizontal surfaces perpendicular to the pressing directions D1 and D2, facilitating pressing on the second jig 120 from the top surface 120c and facilitating the first jig 110 to be carried by the base 105 through the bottom surface 120c.

[0046] Please refer to Figure 1 and Figure 2 , the wafer jig structure 100 of this embodiment further includes at least one positioning member 130. Correspondingly, the outer peripheral surface of the first jig 110 has at least one first groove 110b, and the outer peripheral surface of the second jig 120 has at least one second groove 120b. The positioning member 130 is adapted to be partially embedded in the first groove 110b and partially embedded in the second groove 120b to fix the relative positions of the first jig 110 and the second jig 120. And the positioning member 130 can block the wafer W on the first jig 110 when the first jig 110 and the second jig 120 are not yet in contact, preventing the wafer W from sliding off the first jig 110.

[0047] The wafer jig structure 100 of this embodiment may further include Figure 4The two sacrificial layers 140 shown. The two sacrificial layers 140 can be respectively disposed on the first inclined surface 110a of the first jig 110 and the second inclined surface 120a of the second jig 120 to contact the wafer W, so as to prevent the wafer W from directly contacting the first jig 110 and the second jig 120, and unexpectedly generating a chemical reaction at high temperature. For example, if the material of the wafer W is silicon carbide, the material of the sacrificial layer 140 can be the same as that of the wafer W and be a silicon carbide spacer, but the present invention is not limited thereto. Figure 7 It is a partial enlarged view of the first jig, the second jig and the wafer according to another embodiment of the present invention. Figure 7 The embodiment shown and Figure 5 The difference between the shown embodiment and Figure 7 The first jig 110 and the second jig 120 of are respectively coated with a silicon carbide CVD coating on the first inclined surface 110a and the second inclined surface 120a, thus forming the sacrificial layer 140'.

[0048] In other embodiments, the first inclined surface 110a and the second inclined surface 120a can respectively have recesses, so that when the sacrificial layer 140 is a wafer, the wafer can be positioned in the recesses and is less likely to slip. The depth of the recess is greater than the thickness of the sacrificial layer.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wafer fixture structure, characterized in that, comprising: a first fixture having a first inclined surface; and a second fixture having a second inclined surface, wherein the first fixture and the second fixture are mutually abutted such that the first inclined surface faces the second inclined surface and a clamping space is formed between the first inclined surface and the second inclined surface, an outer peripheral portion of the first fixture and an outer peripheral portion of the second fixture surround the clamping space, and there is a gap between the outer peripheral portion of the first fixture and the outer peripheral portion of the second fixture, the distance between the first inclined surface and the second inclined surface is greater than the distance between the outer peripheral portion of the first fixture and the outer peripheral portion of the second fixture.

2. The wafer fixture structure according to claim 1, characterized in that, when the first fixture and the second fixture are mutually abutted, the first fixture and the second fixture together form a cylindrical structure.

3. The wafer fixture structure according to claim 1, characterized in that, further comprising at least one positioning member, wherein at least one first groove is provided on an outer peripheral surface of the first fixture, at least one second groove is provided on an outer peripheral surface of the second fixture, and the at least one positioning member is adapted to be partially embedded in the at least one first groove and partially embedded in the at least one second groove.

4. The wafer fixture structure according to claim 1, characterized in that, further comprising a force-applying assembly, wherein the force-applying assembly is adapted to be connected to the first fixture and the second fixture and apply an external force to the first fixture and the second fixture.

5. The wafer fixture structure according to claim 1, characterized in that, further comprising two sacrificial layers, and the two sacrificial layers are adapted to be respectively disposed on the first inclined surface and the second inclined surface to contact the wafer.

6. The wafer fixture structure according to claim 5, characterized in that, each of the sacrificial layers is a silicon carbide spacer or a silicon carbide CVD coating.

7. The wafer fixture structure according to claim 1, characterized in that, the first fixture has a bottom surface relative to the first inclined surface, the second fixture has a top surface relative to the second inclined surface, and both the bottom surface and the top surface are horizontal surfaces.

8. A wafer fixture structure, characterized in that, comprising: a first fixture having a first inclined surface; and a second fixture having a second inclined surface, wherein when the first fixture and the second fixture are mutually abutted and clamp the wafer between the first inclined surface and the second inclined surface, the first inclined surface and the second inclined surface are parallel to each other and inclined to the pressing direction, and the first fixture and the second fixture are adapted to press the wafer by an external force applied along the pressing direction, the distance between the first inclined surface and the second inclined surface is greater than the distance between the outer peripheral portion of the first fixture and the outer peripheral portion of the second fixture.

9. A wafer processing apparatus, characterized in that, comprising: the wafer fixture structure according to claim 8; and a heat source adapted to heat the wafer clamped between the first inclined surface and the second inclined surface.

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