Wafer polishing method and polishing apparatus

Abstract

The present application belongs to the field of precision grinding, and discloses a wafer grinding method, which can obtain extremely high wafer surface quality and maintain extremely high wafer grinding efficiency without changing the grinding platform. The wafer is placed on a rotating predetermined grinding surface, a grinding liquid film is injected between the predetermined grinding surface and the wafer, the wafer and the predetermined grinding surface are separated by the grinding liquid film, and the two are made to rotate relatively. A concave mirror surface recessed towards the predetermined grinding surface is arranged directly below the predetermined grinding surface, and an upwardly emitting laser beam is arranged directly below the concave mirror surface, the laser beam is diffused through the concave mirror surface to form an auxiliary heating light spot covering the grinding liquid film, so that the auxiliary heating light spot heats the grinding liquid film, and the predetermined grinding surface grinds the wafer. The present application also discloses a wafer grinding device for implementing the above grinding method, and the device has a simple structure.

Description

Technical Field

[0001] This invention belongs to the field of precision grinding, specifically relating to a wafer grinding method and grinding apparatus. Background Technology

[0002] Currently, precision grinding of wafers mainly employs a combination of mechanical grinding and chemical mechanical polishing (CMP). Traditional single-sided grinding equipment typically includes basic components such as a grinding disc, workpiece fixing device, grinding slurry supply system, and pressure application system. For example, the grinding machine produced by Dongguan Shenggao Grinding Technology Co., Ltd. uses a working method of "counter-clockwise rotation of the grinding disc, workpiece rotation driven by a correction wheel, and gravity pressure." Although this type of equipment can achieve a certain degree of flatness, it mainly relies on purely mechanical action, resulting in limited material removal rate and a tendency to produce scratches and subsurface damage on the processed surface.

[0003] For applications requiring higher precision, such as the processing of YAG wafers, existing technologies employ multi-step grinding and polishing processes, such as a combination of boron carbide rough grinding, alumina fine grinding, and diamond bonded abrasive polishing. While this method can achieve high surface quality, the related equipment and processes are complex, time-consuming, and require frequent changes to abrasives and equipment settings. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the present invention provides a simple wafer grinding method and grinding apparatus, which can simultaneously obtain extremely high wafer surface quality and maintain extremely high wafer grinding efficiency without changing the grinding platform.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A wafer polishing method involves placing a wafer on a rotating predetermined polishing surface, injecting a polishing slurry film between the predetermined polishing surface and the wafer, separating the wafer and the predetermined polishing surface through the polishing slurry film and causing them to rotate relative to each other; a concave mirror surface recessed towards the predetermined polishing surface is provided directly below the predetermined polishing surface, and an upward-emitting laser beam is provided directly below the concave mirror surface; the laser beam diffuses through the concave mirror surface to form an auxiliary heating spot covering the polishing slurry film, thereby heating the polishing slurry film, while the predetermined polishing surface polishes the wafer.

[0006] Preferably, the predetermined grinding surface and the concave mirror surface are made into two opposing surfaces of the transparent grinding disc, and a positive pressure is applied to the wafer toward the predetermined grinding surface.

[0007] Preferably, the predetermined grinding surface is divided into at least two grinding areas, and a wafer is placed in each grinding area.

[0008] Furthermore, when the wafer is placed on the predetermined grinding surface, the wafer has one rotational degree of freedom and two translational degrees of freedom. By constraining the two translational degrees of freedom, the wafer is constrained within the corresponding grinding area when the predetermined grinding surface and the wafer rotate relative to each other.

[0009] A wafer grinding apparatus for grinding wafers includes: a self-rotating transparent grinding disc having a horizontal predetermined grinding surface and a concave mirror surface, the concave mirror surface being directly below the predetermined grinding surface and recessed toward the predetermined grinding surface; a grinding slurry injection pipe with its opening facing the predetermined grinding surface; and a laser emitter having a vertically upward emitting head located directly below the concave mirror surface, with the emission direction coaxial with the principal optical axis of the concave mirror surface.

[0010] Preferably, the present invention further includes a device base, a drive motor, and a grinding disc mounting frame. The drive motor is disposed in the device base, and the output shaft of the drive motor is connected to the bottom of the grinding disc mounting frame. The transparent grinding disc is detachably disposed on the top of the grinding disc mounting frame, and the top of the grinding disc mounting frame is open to the concave mirror surface. The main optical axis of the concave mirror surface is coaxial with the output shaft of the drive motor. There is a space between the top and bottom of the grinding disc mounting frame. The laser emitter is disposed in the space between the frame via a cross slide, thereby giving the laser emitter two degrees of freedom of movement.

[0011] Furthermore, the edge of the concave mirror extends to form a skirt facing the grinding disc mounting bracket, and the top of the grinding disc mounting bracket forms a ring-shaped mounting body. The mounting body extends along its own extension direction to form a continuous closed mounting step, and the edge of the mounting skirt is inserted into the mounting step, so that the transparent grinding disc is detachably mounted on the mounting body.

[0012] Furthermore, the present invention also includes a pair of clamping arc hoops, which are disposed facing each other and detachably on the upper surface of the combined entity. When the pair of clamping arc hoops move towards each other or away from each other, the transparent grinding disc is fixed relative to the grinding disc mounting frame by clamping the combined skirt.

[0013] Furthermore, the present invention also includes a plurality of constraint components arranged around the transparent grinding disc. Each constraint component includes a constraint rod and a constraint ring. The constraint rod has a coupling side and a constraint side. The coupling side is disposed on the device base, and the constraint side forms a constraint position. The constraint position is located within the grinding area, and the constraint position has a pair of constraint protrusions distributed along the circumference of the transparent grinding disc. The constraint ring is correspondingly sleeved on the outer periphery of the wafer, and the pair of constraint protrusions respectively roll in contact with the outer peripheral surface of the constraint ring. The wrap angle corresponding to the pair of contact points formed by the pair of constraint protrusions on the outer periphery of the constraint ring is greater than or equal to 120°.

[0014] Furthermore, the constraint assembly also includes a pair of constraint guide wheels, which are correspondingly disposed on a pair of constraint protrusions, and the constraint guide wheels and the constraint ring are externally tangent and in rolling contact.

[0015] Furthermore, the device base has a chip collection hole, the transparent grinding disc is coaxial with the chip collection hole and located at a predetermined distance directly above the chip collection hole, the diameter of the chip collection hole is larger than the diameter of the transparent grinding disc, the device base is also provided with a chip discharge channel, and the chip collection hole is open to the outside through the chip discharge channel.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Because the wafer polishing method of the present invention involves placing a wafer on a rotating predetermined polishing surface, injecting a polishing slurry film between the predetermined polishing surface and the wafer, separating the wafer and the predetermined polishing surface through the polishing slurry film, and causing them to rotate relative to each other; a concave mirror surface recessed towards the predetermined polishing surface is provided directly below the predetermined polishing surface, and an upward-emitting laser beam is provided directly below the concave mirror surface. The laser beam diffuses through the concave mirror surface to form an auxiliary heating spot covering the polishing slurry film, thereby heating the polishing slurry film, while the predetermined polishing surface polishes the wafer. Specifically, the polishing process is the process of removing silicon dioxide from the wafer surface through a hydrolysis reaction of the bases in the polishing slurry. Under heating, the silicon-oxygen bonds on the wafer surface are more easily broken, which significantly accelerates the hydrolysis reaction, so that the polishing slurry can quickly remove silicon dioxide from the wafer surface, completing the polishing of the wafer. Therefore, the present invention can obtain extremely high wafer surface quality and maintain extremely high wafer polishing efficiency without changing the polishing platform.

[0017] 2. Because the present invention makes the predetermined grinding surface and the concave mirror surface into two opposing surfaces of the transparent grinding disc, the present invention simplifies the setting of the universal transparent grinding disc setting component.

[0018] 3. Because the wafer has one rotational degree of freedom and two translational degrees of freedom when it is placed on the predetermined grinding surface, and the two translational degrees of freedom are constrained, the wafer is constrained within the corresponding grinding area when the predetermined grinding surface and the wafer rotate relative to each other. Therefore, the present invention can grind multiple wafers simultaneously, thereby further improving the grinding efficiency.

[0019] 4. Because the present invention also includes a device base, a drive motor, and a grinding disc mounting frame, the drive motor is installed inside the device base, the output shaft of the drive motor is connected to the bottom of the grinding disc mounting frame, the transparent grinding disc is detachably mounted on the top of the grinding disc mounting frame, and the top of the grinding disc mounting frame is open towards the concave mirror surface. The main optical axis of the concave mirror surface is coaxial with the output shaft of the drive motor. There is a space between the top and bottom of the grinding disc mounting frame, and the laser emitter is mounted in the space through a cross slide, thus the laser emitter has two degrees of freedom of movement. Therefore, the present invention not only avoids mutual installation interference between the output shaft of the drive motor and the laser emitter through the grinding disc mounting frame, but also makes the emission direction of the laser emitter adjustable through the cross slide, thereby ensuring that the laser emission direction is coaxial with the main optical axis of the concave mirror surface.

[0020] 5. Because the edge of the concave mirror surface of the present invention extends to form a skirt facing the grinding disc mounting frame, and the top of the grinding disc mounting frame forms a ring-shaped mounting body, the mounting body extends along its own extension direction to form a continuous closed mounting step, and the edge of the mounting skirt is inserted into the mounting step, so that the transparent grinding disc is detachably mounted on the mounting body. Therefore, the present invention ensures that the transparent grinding disc is stably mounted on the top of the grinding disc mounting frame through the mounting step.

[0021] 6. Because the present invention also includes a pair of clamping arc hoops, which are disposed facing each other and detachably on the upper surface of the combined entity, when the pair of clamping arc hoops move towards each other or away from each other, the transparent grinding disc is fixed relative to the grinding disc mounting frame by clamping the combined skirt. Therefore, the present invention enables the transparent grinding disc to be fixedly positioned on the top of the grinding disc mounting frame by means of a pair of clamping arc hoops.

[0022] 7. Because the wafer polishing apparatus of the present invention further includes multiple constraint components arranged around a transparent polishing disc, each constraint component includes a constraint rod and a constraint ring. The constraint rod has a coupling side and a constraint side. The coupling side is disposed on the device base, and the constraint side forms a constraint position. The constraint position is located within the polishing area, and the constraint position has a pair of constraint protrusions distributed circumferentially along the transparent polishing disc. The constraint ring is correspondingly sleeved on the outer periphery of the wafer, and the pair of constraint protrusions respectively roll in contact with the outer peripheral surface of the constraint ring. The wrap angle corresponding to the pair of contact points formed by the pair of constraint protrusions on the outer periphery of the constraint ring is greater than or equal to 120°. Therefore, the present invention constrains multiple wafers within the corresponding polishing area through the constraint components.

[0023] 8. Because the constraint assembly of the present invention also includes a pair of constraint guide wheels, which are correspondingly disposed on a pair of constraint protrusions, and the constraint guide wheels and the constraint ring are externally tangential and in rolling contact, that is, when the transparent grinding disc drives the wafer to rotate, it simultaneously drives the constraint ring to rotate. At this time, at least one constraint guide wheel is not parallel to the direction of rotation of the constraint ring in the tangential direction formed on the outer periphery of the constraint ring, so that the constraint guide wheel and the constraint ring rotate relative to each other, so that the constraint ring rotates smoothly and drives the wafer to rotate. Therefore, the present invention makes the wafer rotate more smoothly by setting a pair of constraint guide wheels and a constraint ring. Attached Figure Description

[0024] Figure 1 A perspective view of a wafer grinding apparatus according to an embodiment of the present invention. Figure 1 .

[0025] Figure 2 A perspective view of a wafer grinding apparatus according to an embodiment of the present invention. Figure 2 (A rough sketch of a transparent grinding disc).

[0026] Figure 3 This is an assembly diagram of the drive motor, grinding disc mounting bracket, cross slide, clamping arc hoop, and transparent grinding disc, which are embodiments of the present invention.

[0027] Figure 4 for Figure 3 Cross-sectional view (drive motor is sketched).

[0028] Figure 5 Exploded view of the millstone mounting frame, cross slide, and clamping hoop.

[0029] Figure 6 This is a schematic diagram of the constraint component according to an embodiment of the present invention (the constraint ring is omitted).

[0030] In the diagram: 100, wafer grinding apparatus; 10, apparatus base; 10a, top surface; 10b, chip collection hole; 10c, chip discharge channel; M, drive motor; 20, grinding disc mounting frame; 20a, space within the frame; 21, support plate; 22, connecting entity; 22a, connecting step; 30, transparent grinding disc; 30a, predetermined grinding surface; 30b, concave mirror surface; 30c, connecting skirt; 40, laser emitter; 40a, emitter head; W, cross slide; W1. First direction slider, W2, second direction slider, 50, clamping arc hoop, 50a, sliding waist hole, 50b, arc hoop end, 60, constraint assembly, 61, constraint rod, 61a, coupling side, 61b, constraint side, 61c, constraint protrusion, 61d, mating waist groove, 62, constraint guide wheel, 63, constraint ring, 64, mounting base, 64a, lifting waist hole, 65, connector, 65a, plug-in protrusion, 70, grinding fluid supply device, 70a, grinding fluid injection pipe. Detailed Implementation

[0031] To make the technical means, creative features, objectives and effects of the present invention easier to understand, the following embodiments, in conjunction with the accompanying drawings, specifically illustrate the wafer grinding method and grinding apparatus of the present invention. It should be noted that the description of these embodiments is for the purpose of helping to understand the present invention, but does not constitute a limitation of the present invention.

[0032] In the wafer polishing method of this embodiment, a wafer is placed on a rotating predetermined polishing surface, and a polishing slurry film is injected between the predetermined polishing surface and the wafer. The wafer and the predetermined polishing surface are separated by the polishing slurry film, and the two rotate relative to each other.

[0033] Specifically, the polishing process is the removal of SiO2 (oxide, hereinafter the same) from the surface of the wafer. The polishing slurry contains not only abrasive grains for polishing but also OH groups. - (Bases, the same below), through OH - It undergoes a hydrolysis reaction with SiO2, thereby softening SiO2 and making it easier to grind out.

[0034] The hydrolysis reaction formula is: Among them, since silicate tetrahydrate (Si(OH)4) is soluble in water, the oxides after the reaction are easily removed by abrasive particles in an aqueous environment.

[0035] A concave mirror is set directly below the predetermined grinding surface, and an upward-emitting laser beam is set directly below the concave mirror. The laser beam diffuses through the concave mirror to form an auxiliary heating spot covering the grinding slurry film. The auxiliary heating spot heats the grinding slurry film, while the predetermined grinding surface grinds the wafer.

[0036] Specifically, under the irradiation of the auxiliary heating spot, the polishing slurry film of the corresponding wafer is locally heated, generating high temperature and electric field. At the same time, the laser excites electrons on the wafer surface, making it easier to break the silicon-oxygen bonds (Si-O) of the oxide. These two aspects greatly increase the speed of the hydrolysis reaction.

[0037] The predetermined grinding surface and the concave mirror surface are made into two opposing surfaces of the transparent grinding disc. Specifically, the transparent grinding disc is made of transparent glass, which simultaneously has the shape of both the predetermined grinding surface and the concave mirror surface and the function of both.

[0038] A positive pressure is applied to the wafer toward a predetermined grinding surface, so that the predetermined grinding surface can effectively grind the wafer when it rotates relative to the wafer.

[0039] The predetermined grinding surface is divided into at least two grinding areas, and each grinding area corresponds to a wafer. Specifically, the predetermined grinding surface is much larger than the grinding area, so that multiple grinding areas can be set at the same time, so that multiple wafers can be ground using a predetermined grinding surface at the same time.

[0040] When a wafer is placed on a predetermined grinding surface, the wafer has one rotational degree of freedom and two translational degrees of freedom. By constraining the two translational degrees of freedom, the wafer is constrained within the corresponding grinding area when the predetermined grinding surface and the wafer rotate relative to each other. Specifically, the wafer is ground by rotating relative to the predetermined grinding surface. To achieve this effect, its mobility should be constrained.

[0041] like Figure 1 and Figure 2 As shown, the wafer polishing apparatus 100 for implementing the above polishing method includes an apparatus base 10, a polishing disc mounting frame 20, a transparent polishing disc 30, a laser emitter 40, a clamping arc hoop 50, a constraint assembly 60, and a polishing slurry supply device 70.

[0042] The device base 10 has a top surface 10a, a chip collection hole 10b, and a chip discharge channel 10c.

[0043] The chip collection hole 10b is open to the outside through the chip discharge channel 10c. Specifically, the device base 10 is hollow, the top surface 10a is horizontally set, the chip collection hole 10b is a sinking circular hole formed on the top surface 10a, one end of the chip discharge channel 10c is located on the bottom surface of the chip collection hole 10b, and the other end is open to the outside.

[0044] The drive motor M is located inside the device base 10. The output shaft of the drive motor M is vertically upward and extends from the center of the chip collection hole 10b.

[0045] The bottom of the grinding disc mounting bracket 20 is connected to the output shaft of the drive motor M. The top of the grinding disc mounting bracket 20 is open towards the transparent grinding disc 30. There is a space 20a between the top and bottom of the grinding disc mounting bracket 20. The top of the grinding disc mounting bracket 20 forms a ring-shaped connecting entity 22. The connecting entity 22 extends along its own extension direction to form a continuous closed connecting step. Specifically, as shown... Figure 3 As shown, the drive motor M, the grinding disc mounting frame 20, and the transparent grinding disc 30 are coupled sequentially from bottom to top, and both the grinding disc mounting frame 20 and the transparent grinding disc 30 are located outside the device base 10. The grinding disc mounting frame 20 has a double-layer plate structure, including a bearing plate 21 and a connecting entity 22 that are parallel to each other. The bearing plate 21 is located at the bottom of the grinding disc mounting frame 20, that is, it is set on the output shaft of the drive motor M, so that the drive motor M can drive the grinding disc mounting frame 20 to rotate. A space 20a is formed between the bearing plate 21 and the connecting entity 22.

[0046] The transparent grinding disc 30 is detachably mounted on the top of the grinding disc mounting bracket 20, so that when the grinding disc mounting bracket 20 rotates, it drives the transparent grinding disc 30 to rotate as well.

[0047] like Figure 4 As shown, the transparent grinding disc 30 has a horizontal predetermined grinding surface 30a and a concave mirror surface 30b. The concave mirror surface 30b is located directly below the predetermined grinding surface 30a and is recessed towards the predetermined grinding surface 30a. The bonding entity 22 faces the concave mirror surface 30b. Specifically, multiple grinding areas (not shown in the figure) are evenly and continuously distributed in the outer ring area of ​​the edge of the predetermined grinding surface 30a. Each grinding area corresponds to grinding a wafer B1. In order to enhance the friction, a pressure block B2 is placed on the upper surface of the wafer B1 to apply axial grinding pressure to the wafer B1.

[0048] Specifically, the rotation axis of the predetermined grinding surface 30a, the main optical axis of the concave mirror surface 30b, and the output shaft of the drive motor M are coaxial. The diameter of the chip collection hole 10b is larger than the diameter of the transparent grinding disk 30. Furthermore, in the vertical direction, the transparent grinding disk 30 does not obstruct the opening of the chip discharge channel 10c. Therefore, the chips generated during wafer grinding will ultimately be automatically or manually removed from the predetermined grinding surface 30a into the chip collection hole 10b, and automatically or manually discharged from the chip discharge channel 10c. In this embodiment, the transparent grinding disk 30 is made of glass.

[0049] The edge of the concave mirror 30b extends to form a connecting skirt 30c facing the grinding disc mounting bracket 20. The edge of the connecting skirt 30c is inserted into the connecting step 22a, so that the transparent grinding disc 30 is detachably mounted on the connecting body 22.

[0050] The laser emitter 40 is mounted on the upper surface of the support plate 21 via a cross slide W, i.e., within the space 20a in the frame. The laser emitter 40 has a vertically upward-facing emitting head 40a, which is located directly below the concave mirror 30b, and its emission direction is coaxial with the main optical axis of the concave mirror 30b. Specifically, the emission direction of the emitting head 40a, the main optical axis of the concave mirror 30b, and the output shaft of the drive motor M are coaxial.

[0051] The laser emitter 40 has two degrees of freedom of movement. Specifically, the cross slide W has a first direction slider W1 and a second direction slider W2, and the first direction slider W1 and the second direction slider W2 have mutually perpendicular degrees of freedom of movement. The laser emitter 40 is mounted on the second direction slider W2. The cross slide W is mounted on the upper surface of the support plate 21, that is, inside the frame space 20a. The frame space 20a is circumferentially open outward, so that the operator (not shown in the figure) can operate the cross slide W from the outside. That is, the operator can move the first direction slider W1 in the first horizontal direction by manually adjusting the knob, and the second direction slider W1 can be moved in the second horizontal direction by manually adjusting the knob. Thus, the laser emitter 40 can be positioned within a predetermined horizontal range, thereby ensuring that the emission direction of the emitting head 40a is coaxial with the principal optical axis of the concave mirror surface 30b.

[0052] like Figure 5 As shown, there is a pair of clamping arc hoops 50. The pair of clamping arc hoops 50 are detachably mounted on the upper surface of the connecting entity 22 facing each other. When the pair of clamping arc hoops 50 move towards or away from each other, the transparent grinding disc 30 is fixed relative to the grinding disc mounting frame 20 by clamping the connecting skirt 30c.

[0053] Specifically, the diameter formed by the connecting step 22a is larger than the maximum outer diameter of the connecting skirt 30c. Therefore, after the connecting skirt 30c is inserted into the connecting step 22a, the transparent grinding disc 30 is in an unfixed state relative to the connecting entity 22. The clamping arc hoop 50 is semi-circular, with a sliding waist hole 50a and a pair of arc hoop ends 50b. The sliding waist hole 50a extends radially along the clamping arc hoop 50, and the clamping arc hoop 50 is locked by bolts passing through the sliding waist hole 50a and a through hole (not shown in the attached figure) on the upper surface of the connecting entity 22. The pair of arc hoop ends 50b are located at the two ends of the extended arc of the clamping arc hoop 50. Each arc hoop... The end 50b has a locking through hole (not shown in the figure). The two pairs of locking through holes of a pair of clamping arc hoops 50 correspond to each other. When a pair of clamping arc hoops 50 can move radially along the clamping arc hoops 50 through the sliding waist hole 50a to fit against the surface of the connecting skirt 30c, a pair of clamping arc hoops 50 are simultaneously passed through the two pairs of locking through holes by a pair of bolts, so that the transparent grinding disc 30 is fixed relative to the connecting entity 22. Therefore, after each time the transparent grinding disc 30 is fixed relative to the connecting entity 22, the direction of the concave mirror surface 30b will inevitably change. When the change is large, it is necessary to adjust the position of the laser emitter 40 by means of the cross slide W.

[0054] The number of constraint components 60 is multiple, and the multiple constraint components 60 are arranged around the transparent grinding disc 30. Specifically, the multiple constraint components 60 are all arranged on the top surface 10a.

[0055] like Figure 6As shown, the constraint assembly 60 includes a constraint rod 61, a constraint guide wheel 62, and a constraint ring 63.

[0056] The constraint member 61 has a coupling side 61a and a constraint side 61b. The coupling side 61a is disposed on the device base 10, and the constraint side 61b forms a constraint position (not shown in the figure). The constraint position is located in the grinding area, and the constraint position has a pair of constraint protrusions 61c distributed circumferentially along the transparent grinding disc 30. Specifically, the constraint side 61b is located above the grinding area and does not contact the grinding area. In the vertical direction, the constraint side 61b corresponds to the grinding area.

[0057] Specifically, the constraint assembly 60 also includes a mounting base 64 and a connector 65. The mounting base 64 is disposed on the top surface 10a and has a vertically extending lifting groove 64a. The connector 65 is rod-shaped, with one end of the connector 65 inserted into the lifting groove 64a and movable in the vertical direction. A protruding insertion protrusion 65a is formed on the circumferential surface of the other end. The constraint rod 61 has a horizontally extending mating groove 61d, with the insertion protrusion 65a inserted into the mating groove 61d and movable in the horizontal direction. Thus, the constraint rod 61 has both a vertical degree of freedom and a horizontal degree of freedom.

[0058] The number of constraint guide wheels 62 is one pair, and the pair of constraint guide wheels 62 are respectively set on a pair of constraint protrusions 61c, and have horizontal rotational degrees of freedom.

[0059] The constraint ring 63 is fitted around the outer periphery of the wafer B1, and a pair of constraint guide wheels 62 are tangentially and rollingly contacting the outer periphery of the constraint ring 63. A pair of constraint protrusions 61c form a pair of contact points on the outer periphery of the constraint ring 63, with the wrap angle of the constraint ring 63 being greater than or equal to 120°. Specifically, the wafer B1 and the pressure block B2 are both located inside the constraint ring 63, and the outer edge of the wafer B1 is slightly interference-fitted with the inner ring surface of the constraint ring 63. Thus, when the constraint ring 63 moves, it will drive the wafer B1 and the pressure block B2 to move together.

[0060] Specifically, when wafer B1 is located on the horizontal predetermined grinding surface 30a, wafer B1 has two translational degrees of freedom and one rotational degree of freedom remaining out of its six spatial degrees of freedom. By setting a pair of constraint sides 61b and constraint ring 63, wafer B1 has only one rotational degree of freedom left, which can only rotate on its own axis, while the two translational degrees of freedom are constrained, thus wafer B1 is constrained within the corresponding grinding area.

[0061] Specifically, when the transparent grinding disc 30 drives the wafer B1 to rotate along the circumference of the transparent grinding disc 30, it simultaneously drives the constraint ring 63 to rotate. At this time, the velocity vector direction of the constraint ring 63 is the tangential direction of the transparent grinding disc 30. Meanwhile, at least one constraint guide wheel 62 forms a tangential direction on the outer circumference of the constraint ring 63 that is not parallel to the direction of rotation of the constraint ring 63, i.e., the tangential direction of the transparent grinding disc 30. As a result, the constraint guide wheel 62 and the constraint ring 63 rotate relative to each other, allowing the constraint ring 63 to rotate smoothly and drive the wafer B1 to rotate. By adjusting the friction coefficient between the predetermined grinding surface and the wafer B1, and the friction coefficient between the constraint guide wheel 62 and the constraint ring 63, the wafer B1 carrying the pressure block B2 can rotate relative to the predetermined grinding surface, thereby producing a grinding effect on the wafer B1.

[0062] The inlet of the polishing slurry injection pipe 70a faces the predetermined polishing surface 30a. Specifically, a polishing slurry supply device 70 is provided near the device housing 10, and the polishing slurry injection pipe 70a is the output end of the polishing slurry supply device 70.

[0063] The above embodiments are preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Various modifications or variations that can be made by those skilled in the art without creative effort within the scope of the appended claims are still within the scope of protection of this patent.

Claims

1. A wafer grinding method, Its features are: in, A wafer is placed on a rotating predetermined grinding surface, and a polishing slurry film is injected between the predetermined grinding surface and the wafer. The wafer and the predetermined grinding surface are separated by the polishing slurry film, and the two rotate relative to each other. A concave mirror is disposed directly below the predetermined grinding surface and facing the predetermined grinding surface. A laser beam emitted upward is disposed directly below the concave mirror. The laser beam diffuses through the concave mirror to form an auxiliary heating spot covering the grinding slurry film. The auxiliary heating spot heats the grinding slurry film, while the predetermined grinding surface grinds the wafer.

2. The wafer grinding method according to claim 1, characterized in that: in, The predetermined grinding surface and the concave mirror surface are made into two opposing surfaces of a transparent grinding disc, and a positive pressure is applied to the wafer toward the predetermined grinding surface.

3. The wafer grinding method according to claim 1 or 2, characterized in that: in, The predetermined grinding surface is divided into at least two grinding regions, and each grinding region corresponds to a wafer.

4. The wafer grinding method according to claim 3, characterized in that: in, When the wafer is placed on the predetermined grinding surface, the wafer has one rotational degree of freedom and two translational degrees of freedom. The two translational degrees of freedom are constrained so that when the predetermined grinding surface and the wafer rotate relative to each other, the wafer is constrained within the corresponding grinding area.

5. A wafer grinding apparatus for grinding wafers, characterized in that, include: A self-rotating transparent grinding disc has a horizontal predetermined grinding surface and a concave mirror surface, the concave mirror surface being located directly below the predetermined grinding surface and recessed towards the predetermined grinding surface. The grinding fluid injection tube has its opening facing the predetermined grinding surface. The laser emitter has a vertically upward-facing emitting head located directly below the concave mirror surface, and the emission direction is coaxial with the principal optical axis of the concave mirror surface.

6. The wafer grinding apparatus according to claim 5, characterized in that, Also includes: The device includes a base, a drive motor, and a grinding disc mounting bracket. The drive motor is housed within the base, and its output shaft is connected to the bottom of the grinding disc mounting bracket. The transparent grinding disc is detachably mounted on the top of the mounting bracket, with the top of the bracket opening towards the concave mirror surface. The principal optical axis of the concave mirror surface is coaxial with the output shaft of the drive motor. The grinding wheel mounting frame has a space between its top and bottom, and the laser emitter is mounted in the space via a cross slide, thus giving the laser emitter two degrees of freedom of movement.

7. The wafer grinding apparatus according to claim 6, characterized in that: in, The edge of the concave mirror extends to form a skirt that connects to the grinding disc mounting bracket. The top of the grinding disc mounting bracket has a ring-shaped connecting entity. This connecting entity extends along its own extension direction to form a continuous closed connecting step. The edge of the connecting skirt is inserted into the connecting step, so that the transparent grinding disc can be detachably mounted on the connecting entity.

8. The wafer grinding apparatus according to claim 7, characterized in that, Also includes: A pair of clamping arc hoops are detachably mounted on the upper surface of the combined entity. When the pair of clamping arc hoops move towards or away from each other, they clamp the combined skirt to fix the transparent grinding disc relative to the grinding disc mounting frame.

9. The wafer grinding apparatus according to claim 6, characterized in that, Also includes: Multiple constraint components are arranged around the transparent grinding disc. The constraint assembly includes constraint bars and constraint rings. The constraint rod has a coupling side and a constraint side. The coupling side is disposed on the device base, and the constraint side forms a constraint position located within the grinding area. The constraint position has a pair of constraint protrusions distributed circumferentially along the transparent grinding disc. The constraint ring is correspondingly sleeved on the outer periphery of the wafer, and a pair of constraint protrusions respectively roll in contact with the outer peripheral surface of the constraint ring, and the wrap angle corresponding to the pair of contact points formed by the pair of constraint protrusions on the outer periphery of the constraint ring is greater than or equal to 120°.

10. The wafer grinding apparatus according to claim 9, characterized in that: in, The constraint assembly further includes a pair of constraint guide wheels, which are correspondingly disposed on a pair of constraint protrusions, and the constraint guide wheels and the constraint ring are externally tangent and in rolling contact.

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