阅读说明：本技术 一种大尺寸硅圆片减薄装置及其减薄工艺 (Large-size silicon wafer thinning device and thinning process thereof ) 是由 裴坤羽 祝斌 刘蛟龙 武卫 孙晨光 刘建伟 王聚安 由佰玲 刘园 谢艳 杨春雪 于 2019-11-19 设计创作，主要内容包括：本发明提供一种大尺寸硅圆片减薄装置,包括用于放置硅圆片的载体座、用于放置左砂轮的左砂轮座以及用于放置右砂轮的右砂轮座,所述载体座、所述左砂轮座和所述右砂轮座同轴设置,所述左砂轮座和所述右砂轮座对称设置在所述载体座两侧且与所述载体座并行设置。本发明还提出一种大尺寸硅圆片减薄工艺。本发明尤其是适用于对尺寸直径为280-320mm的硅圆片进行立式双面减薄,结构设计合理且简单,不仅可对硅圆片两侧面同时同步进行磨削,而且各结构配合可控,拆装保养简单,省时省力,保证硅圆片双面减薄的平整度和稳定性,提升工作效率。(The invention provides a large-size silicon wafer thinning device which comprises a carrier seat for placing a silicon wafer, a left grinding wheel seat for placing a left grinding wheel and a right grinding wheel seat for placing a right grinding wheel, wherein the carrier seat, the left grinding wheel seat and the right grinding wheel seat are coaxially arranged, and the left grinding wheel seat and the right grinding wheel seat are symmetrically arranged on two sides of the carrier seat and are arranged in parallel with the carrier seat. The invention also provides a large-size silicon wafer thinning process. The vertical double-side thinning machine is particularly suitable for vertical double-side thinning of silicon wafers with the size diameter of 280-320mm, has reasonable and simple structural design, can simultaneously and synchronously grind the two side surfaces of the silicon wafers, has controllable matching of all structures, is simple to disassemble, assemble and maintain, saves time and labor, ensures the flatness and stability of double-side thinning of the silicon wafers, and improves the working efficiency.)

1. The utility model provides a jumbo size silicon disk attenuate device, its characterized in that, including the carrier seat that is used for placing the silicon disk, be used for placing left emery wheel's left emery wheel seat and be used for placing right emery wheel's right emery wheel seat, the carrier seat the left emery wheel seat with right emery wheel seat coaxial setting, the left side emery wheel seat with right emery wheel seat symmetry sets up carrier seat both sides and with the parallel setting of carrier seat.

2. The large-size silicon wafer thinning device as claimed in claim 1, wherein the carrier base, the left grinding wheel base and the right grinding wheel base are all of circular structure and have the same diameter; the carrier seat is vertically placed.

3. A large-size silicon wafer thinning device as claimed in claim 1 or 2, wherein a placing hole matched with the diameter of the silicon wafer is arranged on the inner side of the carrier seat, a V-shaped boss is arranged at any position of the edge of the placing hole, and the top end of the V-shaped boss is arranged towards the center of the placing hole.

4. The large-size silicon wafer thinning device as claimed in claim 3, wherein the carrier seat is provided with a deep inwardly-directed stepped groove on a side close to the left grinding wheel seat, and an internal gear on a side close to the right grinding wheel seat, and the stepped groove and the internal gear are symmetrically arranged relative to the placing hole.

5. The large-size silicon wafer thinning device as recited in claim 4, wherein the left wheel base comprises a first left disc and a second left disc coaxially arranged, and the first left disc is arranged far away from the carrier base; the left grinding wheel is arranged on one side, far away from the first left disc, of the second left disc.

6. The large-size silicon wafer thinning device as recited in claim 5, wherein the right grinding wheel base comprises a first right disk and a second right disk which are coaxially arranged, and the first right disk is arranged far away from the carrier base; the right grinding wheel is arranged on one side, far away from the first right disc, of the second right disc; and an external gear meshed with the external gear is arranged on the second right disc, and the external gear and the right gear are coaxially arranged.

7. A large size silicon wafer thinning apparatus as claimed in any one of claims 4 to 6 wherein the second left disc outer diameter and the second right disc outer diameter are both adapted to the placement hole inner diameter.

8. A process for thinning large-size silicon wafers, which comprises the use of the thinning apparatus according to any one of claims 1 to 7, and comprises the following steps: s1: carrying out coarse grinding and thinning on the silicon wafer; s2: step thinning is carried out on the silicon wafer; s3: finely grinding and thinning the silicon wafer; in the thinning process, the left grinding wheel seat and the right grinding wheel seat synchronously rotate at the same speed in the reverse direction, and the carrier seat and the right grinding wheel seat rotate in the same direction.

9. The large-size silicon wafer thinning process as claimed in claim 8, wherein the step S2 includes a first stage thinning and a second stage thinning, and the feeding speed of the left grinding wheel and the right grinding wheel in the first stage thinning is greater than that in the second stage thinning.

10. The process of claim 9, wherein the rotation speed of the silicon wafer is constant during the thinning process.

Technical Field

The invention belongs to the technical field of semiconductor monocrystalline silicon grinding, and particularly relates to a large-size silicon wafer thinning device and a thinning process thereof.

Background

The existing silicon wafer gradually develops large-size and thin-slice development, and the conventional small-size silicon wafer has two types of chemical thinning and mechanical thinning. The chemical thinning is to thin the silicon wafer by reacting with the surface layer of the silicon wafer by using a chemical reagent. For large-size silicon wafers, the required chemical reagent tank is limited in size due to large size and area, and the silicon wafers stacked with each other cannot be completely corroded by the chemical reagent, so that uneven thinning is easily caused, and the yield is low. The mechanical thinning is to polish the surface of the silicon wafer by using a grinding wheel, one surface of the silicon wafer is usually polished by using a single grinding wheel, and the other surface of the silicon wafer is processed after the silicon wafer is turned over; for a large-size silicon wafer, the thinning mode has long single-side processing time, cannot ensure the consistency of geometric parameters of two sides, has low productivity and unstable surface quality of a product, and cannot meet the existing production requirement.

Disclosure of Invention

The invention provides a large-size silicon wafer thinning device and a thinning process thereof, which are particularly suitable for a silicon wafer with the size diameter of 280-320mm, and solve the technical problems of inconsistent geometric parameters of two sides of the thinned silicon wafer, unstable surface quality and low production efficiency caused by unreasonable thinning structure design in the prior production technology.

In order to solve the technical problems, the invention adopts the technical scheme that:

the utility model provides a jumbo size silicon disk attenuate device, is including the carrier seat that is used for placing the silicon disk, the left wheel base that is used for placing left emery wheel and the right wheel base that is used for placing right emery wheel, the carrier seat the left side wheel base with right wheel base coaxial setting, the left side wheel base with right wheel base symmetry sets up carrier seat both sides and with the parallel setting of carrier seat.

Furthermore, the carrier seat, the left grinding wheel seat and the right grinding wheel seat are all of circular structures and have the same diameter; the carrier seat is vertically placed.

Further, a placing hole matched with the diameter of the silicon wafer is formed in the inner side of the carrier seat, a V-shaped boss is arranged at any position of the edge of the placing hole, and the top end of the V-shaped boss faces the center of the placing hole.

Further, the carrier seat is close to left side emery wheel seat one side is equipped with inwards along dark ladder groove, is close to right side emery wheel seat one side is equipped with the internal gear, the ladder groove with the internal gear for place the hole symmetry and set up.

Further, the left grinding wheel seat comprises a first left disc and a second left disc which are coaxially arranged, and the first left disc is far away from the carrier seat; the left grinding wheel is arranged on one side, far away from the first left disc, of the second left disc.

Further, the right grinding wheel seat comprises a first right disc and a second right disc which are coaxially arranged, and the first right disc is far away from the carrier seat; the right grinding wheel is arranged on one side, far away from the first right disc, of the second right disc; and an external gear meshed with the external gear is arranged on the second right disc, and the external gear and the right gear are coaxially arranged.

Further, the second left disc outer diameter and the second right disc outer diameter are both matched with the placing hole inner diameter.

A large-size silicon wafer thinning process comprises the step of adopting the thinning device, and the step comprises the following steps: s1: carrying out coarse grinding and thinning on the silicon wafer; s2: step thinning is carried out on the silicon wafer; s3: finely grinding and thinning the silicon wafer; in the thinning process, the left grinding wheel seat and the right grinding wheel seat synchronously rotate at the same speed in the reverse direction, and the carrier seat and the right grinding wheel seat rotate in the same direction.

Further, the step S2 includes a first stage thinning and a second stage thinning, and the feed rate of the left grinding wheel and the right grinding wheel in the first stage thinning is greater than the feed rate in the second stage thinning.

Furthermore, the rotating speed of the silicon wafer is always unchanged in the thinning process.

The large-size silicon wafer thinning device and the thinning process designed by the invention are used for synchronously grinding and thinning the vertical double surfaces of the large-size silicon wafer, have reasonable and simple structural design, can synchronously grind the two side surfaces of the silicon wafer at the same time, are simple in disassembly and maintenance, save time and labor, do not need other auxiliary devices, have good consistency of geometric parameters of the double surfaces of the processed silicon wafer, and have stable process, high production efficiency and high yield. The silicon wafer obtained by using the thinning device has uniform and consistent thinning thickness on two sides, good surface evenness, stable thinning processing process and high working efficiency.

Drawings

FIG. 1 is a schematic structural diagram of a large-sized silicon wafer according to an embodiment of the present invention;

FIG. 2 is an enlarged view of A in accordance with one embodiment of the present invention;

FIG. 3 is an exploded view of an apparatus for thinning large-sized silicon wafers according to an embodiment of the present invention;

FIG. 4 is a perspective view of a carrier mount according to one embodiment of the invention;

FIG. 5 is a top view of one embodiment of the present invention with the carrier seat adjacent the left grinding wheel side;

FIG. 6 is a top view of the carrier housing adjacent the right grinding wheel in accordance with one embodiment of the present invention;

FIG. 7 is a perspective view of a left wheel head of an embodiment of the present invention;

FIG. 8 is a top view of a left wheel head of an embodiment of the present invention;

FIG. 9 is a perspective view of a right wheel head of an embodiment of the present invention;

fig. 10 is a top view of a right wheel head according to an embodiment of the present invention.

In the figure:

10. silicon wafer 11, V-shaped groove 20 and carrier seat

21. Placing hole 22, V-shaped boss 23 and stepped groove

24. Internal gear 30, left grinding wheel seat 31, first left disk

32. A second left disc 33, a first groove 34, a second groove

40. A right grinding wheel seat 41, a first right disc 42 and a second right disc

43. Third groove 44, fourth groove 45, and external gear

50. Left grinding wheel 60 and right grinding wheel

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

The invention provides a large-size silicon wafer, as shown in figure 1, a silicon wafer 10 is a sample wafer obtained by cutting a monocrystalline silicon round rod with the diameter of 280-320mm by a diamond wire, and the sample wafer is ground, thinned, polished, cleaned, sprayed, printed and cut in sequence to finally manufacture a required semiconductor device. Wherein, the outer circumference of the silicon wafer 10 is provided with a V-shaped groove 11 with an outward opening, and the V-shaped groove 11 is used for being matched with a V-shaped boss 22 in the grinding and thinning device for fixing and clamping the silicon wafer 10. The V-shaped groove 11 is positioned on the diameter of the silicon wafer 10, the top end of the V-shaped groove 11 faces the center of the silicon wafer 10, the V-shaped groove 11 is symmetrically arranged relative to the diameter of the silicon wafer 10, and the vertex angle of the V-shaped groove 11 is of an arc structure. The central axis of the V-shaped groove 11 is located at any of four edges of any silicon wafer 10, that is, at any intersection point where four edges of the silicon round bar intersect with the silicon wafer 10, this arrangement is to prevent the silicon wafer 10 from cracking or breaking, because the silicon wafer 10 has more dislocations at the intersection point where the non-silicon round bar edge of the silicon wafer 10 intersects with the silicon wafer 10, and if the groove occurs, cracks are easily generated, which leads to breaking.

Further, as shown in fig. 2, the vertex angle of the V-shaped groove 11 is 89-95 °, when the vertex angle is smaller than 89 °, the width of the V-shaped groove 11 is too narrow, the strength of the V-shaped boss 22 matched with the V-shaped groove is not enough, the clamping stability is low, and the safety risk of vertical placement of the silicon wafer 10 is reduced; when the vertex angle is greater than 70 °, the cut-off lateral width of the silicon wafer 10 is increased, which not only increases the lateral stress of the silicon wafer 10 and increases the risk of scrap, but also reduces the utilization rate of the silicon wafer 10. Preferably, the vertex angle of the V-shaped groove 11 is 90 °, the depth of the V-shaped groove 11 is 1-1.5mm, preferably 1.25mm, at this time, the V-shaped groove 11 has a stable structure, the difference between the cut width and the height of the silicon wafer 10 is small, and the utilization rate of the silicon wafer 10 can be improved to the maximum extent while ensuring the stability of clamping and placing the silicon wafer 10. The V-shaped groove 11 is arranged, so that the overall use of the silicon wafer 10 is not influenced, the silicon wafer is convenient to match and fix with the thinning device, and meanwhile, the use of other structures is ensured under the condition that the abrasion and thinning of the silicon wafer 10 are not influenced.

In the present embodiment, the silicon wafer 10 has a diameter of 280-320mm and a thickness of 1500um, preferably 1000 um.

A large-size silicon wafer thinning device is shown in figure 3 and comprises a carrier seat 20 for placing a silicon wafer 10, a left grinding wheel seat 30 for placing a left grinding wheel 50 and a right grinding wheel seat 40 for placing a right grinding wheel 60, wherein the carrier seat 20, the left grinding wheel seat 30 and the right grinding wheel seat 40 are all vertically placed and horizontally coaxial, the carrier seat 20, the left grinding wheel seat 30 and the right grinding wheel seat 40 are all of disc-shaped structures, the maximum outer diameters of the carrier seat 20, the left grinding wheel seat 30 and the right grinding wheel seat 40 are the same, and the left grinding wheel seat 30 and the right grinding wheel seat 40 are symmetrically arranged on the left side and the right side of the carrier seat 20 and are arranged in parallel with the silicon wafer 10 in. The carrier base 20 is fixed by an external frame body, the left grinding wheel base 30 and the right grinding wheel base 40 are respectively arranged on rotating shafts which are arranged at the same horizontal position and symmetrically, the structure of the frame body and the rotating shafts is a conventional device in the field, the key point of the non-embodiment is that the drawings are omitted.

As shown in fig. 4-6, the carrier seat 20 is provided with a placement hole 21 inside, the placement hole 21 is adapted to the diameter of the silicon wafer 10, the placement hole 21 is disposed at the center of the carrier seat 20 and located at the middle position of the thickness, and the thickness of the placement hole 21 is the same as the thickness of the silicon wafer 10. A V-shaped boss 24 is arranged at any position of the edge of the placing hole 21, the top end of the V-shaped boss 24 is arranged towards the center of the placing hole 24, the V-shaped boss 24 is symmetrically arranged relative to the diameter of the placing hole 21, and the vertex angle of the V-shaped boss 24 is of an arc structure and is matched with the vertex angle of the V-shaped groove 11.

Furthermore, the vertex angle of the V-shaped boss 24 is 89-95 degrees, when the vertex angle is smaller than 89 degrees, the width of the V-shaped boss 24 is too narrow, the strength is insufficient, the clamping stability is low, and the safety risk of vertical placement of the silicon wafer 10 is reduced; when the vertex angle is greater than 70 °, the cut-off lateral width of the silicon wafer 10 is increased, which not only increases the lateral stress of the silicon wafer 10 and increases the risk of scrap, but also reduces the utilization rate of the silicon wafer 10. Preferably, the vertex angle of the V-shaped boss 24 is 90 °, the depth of the V-shaped boss 24 is 1-1.5mm, preferably 1.25mm, at this time, the V-shaped boss 24 has a stable structure, the difference between the cut width and the height of the silicon wafer 10 is small, and the utilization rate of the silicon wafer 10 can be improved to the maximum extent while the silicon wafer 10 is stably placed.

As shown in fig. 5 to 6, the carrier seat 20 is provided with a stepped groove 21 deep inward along one side close to the left wheel head 30, an internal gear 22 is provided on one side close to the right wheel head 40, the stepped groove 21 and the internal gear 22 are symmetrically arranged relative to the placement hole 23, that is, the depth of the stepped groove 21 is the same as the tooth width of the internal gear 22, and the inner diameter of the stepped groove 21 and the top cutting diameter of the internal gear 22 are both larger than the inner diameter of the placement hole 23, so as to avoid interference with grinding of the wheel on the silicon wafer 10.

As shown in fig. 7, the left wheel head 30 includes a first left disc 31 and a second left disc 32 coaxially disposed, the first left disc 31 is disposed away from the carrier base 20, the second left disc 32 is disposed close to the carrier base 20, one side of the first left disc 31 away from the second left disc 32 is connected to an external rotation shaft, and the first left disc 31 and the second left disc 32 can be integrally manufactured or fixedly connected to each other, which is not detailed herein. The outer diameter of the second left disc 32 is adapted to the inner diameter of the placing hole 21, i.e. the outer diameter of the second left disc 32 is the same as the diameter of the silicon wafer 10. A fixing hole for fixing the left grinding wheel 50 is formed in the side, away from the first left disc 31, of the second left disc 32, the left grinding wheel 50 is located on the side of the radius of the second left disc 32, the outer circle edge of the left grinding wheel 50 is slightly larger than the outer circle edge of the first left disc 31, as shown in fig. 8, the inner circle edge of the left grinding wheel 50 is smaller than the outer diameter of the second left disc 32, and the diameter of the left grinding wheel 50 is half of the diameter of the silicon wafer 10. The thickness of the second left disk 32 and the left grinding wheel 50 is greater than the depth of the stepped groove 22 in order to prevent the carrier block 20 from interfering with the left grinding wheel block 30. In the grinding process, the silicon wafer 10 rotates oppositely to the left grinding wheel 50, the left grinding wheel 50 feeds while rotating, and if the diameter of the left grinding wheel 50 is not equal to half of the diameter of the silicon wafer 10, the thickness of the silicon wafer 10 is not uniform in grinding, and the product quality is seriously affected. The left grinding wheel 50 is a circularly arranged grinding wheel, commercially available and omitted herein.

As shown in fig. 8, a first groove 33 with an outward opening is disposed on an outer edge of the first left disc 31, the first groove 33 is U-shaped and disposed along a diameter of the first left disc 33 toward a center of the circle, a lower end surface of the first groove 33 is perpendicular to the diameter of the first left disc 33, and the first groove 33 is symmetrically disposed with respect to the diameter of the first left disc 33. The first recess 33 is provided to fit into a tongue in the upper end cap of the grinding device (not shown). The outer fringe of second left side dish 32 is equipped with opening second recess 34 that sets up outwards, and second recess 34 is big semicircular structure, is located first recess 33 under, and first recess 33, second recess 34 and the fixed orifices that is used for installing left emery wheel 50 all are located the central axis of second left side dish 32, and second recess 33 and left emery wheel 50 are located the diameter both ends of second left side dish 32 respectively. The second grooves 33 are internally tangent to the stepped grooves 21 in the carrier block 20, the second grooves 33 are arranged in the same configuration as the fourth grooves 43 of the right wheel head 40, and the fourth grooves 43 are fixedly provided with external gears 45 engaged with the internal gears 22 in the carrier block 20, as shown in fig. 9. In the present embodiment, the second groove 33 is provided as a space, which is reserved to fit the internal gear 22 in the carrier base 20; since the side of the carrier seat 20 close to the left grinding wheel 50 is the stepped groove 21, the second groove 33 is a vacant arc groove.

As shown in fig. 9, the right wheel carrier 40 includes a first right disc 41 and a second right disc 42 coaxially disposed, the first right disc 41 is disposed away from the carrier 20, the first right disc 41 and the second right disc 42 have the same structure and size as the first left disc 31 and the second left disc 32, that is, the first right disc 41 has the same outer diameter as the first left disc 31, a third groove 43 with an outward opening is disposed on the outer edge of the first right disc 41, and the third groove 43 has the same structure and size as the first groove 33. The outer diameter of the second right disc 42 is matched with the inner diameter of the placing hole 21, namely the diameter of the silicon wafer 10 is the same, the right grinding wheel 60 is fixedly arranged on one side of the second right disc 42 away from the first right disc 41, the position of the right grinding wheel 60 is opposite to that of the left grinding wheel 50, and the size and the structure of the left grinding wheel 60 are the same as those of the left grinding wheel 50, as shown in fig. 10. A fourth groove 44 is formed in the outer periphery of the second right disk 42, the fourth groove 44 has the same structure as the second groove 34, and an external gear 45 is provided in the fourth groove 44, the external gear 45 being engaged with the internal gear 22 in the carrier block 20. The third groove 43, the fourth groove 44 and the right grinding wheel 60 are all located on the central axis of the second right disc 42, and the fourth groove 44 and the right grinding wheel 60 are respectively located at two ends of the diameter of the second right disc 42. In the present embodiment, the thickness of the second right disk 42 and the right grinding wheel 60 is greater than the depth of the stepped groove 22, and the tooth width of the external gear 45 is not greater than the tooth width of the internal gear 23, in order to prevent the carrier block 20 from interfering with the right grinding wheel block 40 in the case where the internal gear 23 and the external gear 45 are normally engaged.

The working process of the embodiment: the silicon wafer 10 is placed in the placing hole 21 in the carrier seat 20, the left grinding wheel seat 30 drives the left grinding wheel 50 to contact with the left side surface of the silicon wafer 10, the right grinding wheel seat 40 drives the right grinding wheel 60 to contact with the right side surface of the silicon wafer 10, and meanwhile, the external gear 45 arranged on the right grinding wheel seat 40 is meshed with the internal gear 23 on the carrier seat 20; the left grinding wheel seat 30 and the right grinding wheel seat 40 reversely and synchronously rotate, so that the left grinding wheel 50 and the right grinding wheel 60 reversely and synchronously rotate, the right grinding wheel seat 40 is meshed with the inner gear 23 through the outer gear 45 to drive the carrier seat 20 and the right grinding wheel seat 40 to rotate in the same direction, namely the silicon wafer 10 and the right grinding wheel 60 rotate in the same direction, and the left grinding wheel 50 reversely rotates relative to the silicon wafer 10; the left grinding wheel seat 30 and the right grinding wheel seat 40 respectively drive the left grinding wheel 50 and the right grinding wheel 60 to rotate and feed, and the silicon wafer 10 is ground synchronously at the same side, so that the two sides of the silicon wafer 10 are synchronously thinned, the thickness grinding of the two sides of the silicon wafer 10 is uniform, the consistency of the thinned thickness is ensured, and compared with the prior art, the thinning efficiency is improved, the grinding quality of the two sides is also ensured, the yield is improved, and the production cost is reduced.

A large-size silicon wafer thinning process adopts the thinning device, and comprises the following steps:

s1: roughly grinding and thinning the silicon wafer 10;

s2: step thinning is carried out on the silicon wafer 10;

s3: finely grinding and thinning the silicon wafer 10;

in the thinning process, the left grinding wheel seat 30 for fixing the left grinding wheel 50 and the right grinding wheel seat 40 for fixing the right grinding wheel 60 rotate reversely, synchronously and at the same speed, and the carrier seat 20 for fixing the silicon wafer 10 and the right grinding wheel seat 40 rotate in the same direction. Since the speed of the silicon wafer 10 is controlled by meshing gears, it is understood that the rotational speed of the silicon wafer 10 is not the same as the rotational speed of the grinding wheel.

Specifically, in the fine grinding and thinning process of S1, the thickness of the sample silicon wafer 10 is a fixed value, and the rotation speeds of the left grinding wheel 50 and the right grinding wheel 60 are set, so that the left grinding wheel 50 and the right grinding wheel 60 synchronously rotate in opposite directions; meanwhile, the feeding speeds of the left grinding wheel 50 and the right grinding wheel 60 are the same, and after grinding for a certain time, coarse grinding and thinning of the silicon wafer 10 are further completed.

In the step thinning process of S2, the step thinning process includes a first stage thinning and a second stage thinning, the first stage thinning is a transitional thinning, the first stage thinning is thicker than the second stage thinning, and the feeding speed of the left grinding wheel 50 and the right grinding wheel 60 in the first stage thinning is further required to be faster than the feeding speed in the second stage thinning. No matter the thinning is performed in the first stage or the thinning is performed in the second stage, the rotating speeds of the left grinding wheel 50 and the right grinding wheel 60 are the same, and after grinding for a certain time, the step thinning of the silicon wafer 10 is further completed.

In the finish grinding thinning process of S3, grinding thinning is continued on the basis of the stepped thinning, in the process, the rotating speed of the left grinding wheel 50 is the same as that of the right grinding wheel 60, the feeding speed of finish grinding thinning is smaller than that in the thinning in the second stage, and after grinding for a certain time, finish grinding thinning of the silicon wafer 10 is further completed.

In this embodiment, the rotation speed of the silicon wafer 10 is constant during the grinding and thinning process.

Taking a sample wafer of a silicon wafer 10 with a diameter of 300mm as an example, the thickness of the sample wafer is 1000um, the thickness requirement after the sample wafer is thinned is 700um, namely, the thinning thickness of the double sides is 300um, and the thinning thickness of the single side is 150 um.

In the coarse grinding and thinning process of S1, the rotation speeds of the left grinding wheel 50 and the right grinding wheel 60 are both 5000-. The feeding speed of the left grinding wheel 50 and the right grinding wheel 60 is 250-.

In the step thinning process of S2, the rotating speed of the left grinding wheel 50 and the right grinding wheel 60 in the first stage thinning process is 4500-5500r/min, and the rotating speed of the silicon wafer 10 is 50-60 r/min. The feeding speed of the left grinding wheel 50 and the right grinding wheel 60 is 100-120um/min, and the thickness can be reduced by 40 +/-5 um after the left grinding wheel and the right grinding wheel are worn for 50-70 s. The rotating speeds of the left grinding wheel 50 and the right grinding wheel 60 in the second stage of thinning are 4500-5500r/min, and the rotating speed of the silicon wafer 10 is 50-60 r/min. The feeding speed of the left grinding wheel 50 and the right grinding wheel 60 is 70-100um/min, and the left grinding wheel and the right grinding wheel can be thinned by 20 +/-5 um after being worn for 30-50 s. The overall reduced thickness of the silicon wafer 10 at this stage is 60 + -5 um.

In the fine grinding and thinning process of S3, the rotating speeds of the left grinding wheel 50 and the right grinding wheel 60 are both 4000-. The feeding speed of the left grinding wheel 50 and the right grinding wheel 60 is 50-80um/min, and the thickness can be reduced by 10 +/-5 um after the grinding is carried out for 10-30 s.

Finally, the silicon wafer 10 with the single-side thinned thickness of 150um and the double-side thinned thickness of 700um can be obtained.

The large-size silicon wafer designed by the invention is characterized in that the V-shaped groove with an angle of 89-95 degrees is arranged on the outer circumference of the silicon wafer, the depth of the V-shaped groove is 1-1.5mm, preferably, the vertex angle of the V-shaped groove is 90 degrees, the depth is 1.25mm, and the V-shaped groove structure is arranged at any intersection point of four ridge lines of the silicon round bar and the silicon wafer, so that the whole use of the silicon wafer is not influenced, the large-size silicon wafer is convenient to be matched and fixed with a thinning device, and the silicon wafer can be prevented from cracking or breaking.

The large-size silicon wafer thinning device and the thinning process designed by the invention are used for synchronously grinding and thinning the vertical double surfaces of the large-size silicon wafer, have reasonable and simple structural design, can synchronously grind the two side surfaces of the silicon wafer at the same time, are simple in disassembly and maintenance, save time and labor, do not need other auxiliary devices, have good consistency of geometric parameters of the double surfaces of the processed silicon wafer, and have stable process, high production efficiency and high yield. The silicon wafer obtained by using the thinning device has uniform and consistent thinning thickness on two sides, good surface evenness, stable thinning processing process and high working efficiency.

The embodiments of the present invention have been described in detail, and the description is only for the preferred embodiments of the present invention and should not be construed as limiting the scope of the present invention. All equivalent changes and modifications made within the scope of the present invention shall fall within the scope of the present invention.