TW202342232A - Carrier for double-sided polishing, and double-sided polishing method and apparatus for silicon wafer using same - Google Patents

Abstract

Provided are a double-side polishing carrier capable of extending the life of the carrier by improving wear resistance, and a method and apparatus for polishing both sides of silicon wafers using the carrier. The double-sided polishing carrier 10 according to the present invention comprises a substantially cylindrical carrier body 11 made of a resin laminated plate including a fiber base material and a wafer holding hole 12 formed in the carrier body 11. The fiber exposure rate of the main surface of the carrier body 11 is less than 50%.

Description

Carrier for double-sided grinding and double-sided grinding method and device of silicon wafer using the same

The present invention relates to a carrier for double-side polishing and a method and device for double-side polishing of a silicon wafer using the same.

Silicon wafers are widely used as substrate materials for semiconductor devices. Silicon wafers are manufactured by sequentially performing steps such as outer ring grinding, slicing, grinding, etching, double-sided grinding, single-sided grinding, and cleaning on a silicon single crystal ingot. Among them, the double-side polishing step is a necessary step to process the wafer to a predetermined thickness and improve the flatness of the wafer, and is performed using a double-side polishing device that polishes both sides of the wafer simultaneously.

The double-side polishing device uses a double-side polishing carrier that holds the wafer during polishing. The material of the carrier for double-sided polishing includes metal carriers and resin carriers. Metal carriers have a long life due to their high wear resistance, but there are problems such as scratches on the wafer end surface and melting of metal components. Although resin carriers do not suffer from scratches on the wafer end surface or melting of metal components, they have problems with low wear resistance and short lifespan.

Patent Document 1 describes a method of performing double-side polishing while holding a silicon wafer using a resin double-side polishing carrier. The carrier for double-sided polishing is composed of a resin laminate in which a hydrophilic fiber base material is impregnated with a moistening resin. The average contact angle of the front and back surfaces in contact with the polishing cloth with respect to pure water is 45° or more and 60° or less. In addition, the surface exposure rate of the fiber base material reaches more than 50%. According to the resin carrier described in Patent Document 1, the polishing rate of silicon wafers can be increased.

Furthermore, Patent Document 2 describes that before the carrier is put into the double-sided polisher to actually process the wafer, a device other than the wafer polishing device is used to perform primary polishing using a slurry containing abrasive grains, Two-stage carrier grinding (pre-treatment) consisting of secondary grinding without abrasive slurry. [Advanced technical documents] [Patent Document]

[Patent Document 1] International Publication No. 2018/105306 [Patent Document 2] Japanese Patent Application Publication No. 2017-104958

[Problem to be solved by the invention]

However, the conventional double-sided polishing carrier described in Patent Document 1 has a surface exposure rate of more than 50% of the fiber base material. Therefore, even if the polishing rate is increased, the carrier wears quickly, resulting in an increase in the frequency of carrier replacement, resulting in production losses. The issue of increased costs. In addition, generally the variation in wafer flatness quality is greatest just after the carrier is replaced. Therefore, the higher the frequency of carrier replacement, the more the number of wafers that do not meet the required flatness quality increases. In addition, resin carriers containing glass fiber substrates have an increased chance of scratching the wafer surface due to the abrasive sheets of glass fiber.

Therefore, the object of the present invention is to provide a carrier for double-side polishing that can achieve a longer life by improving wear resistance, and a method and device for double-side polishing of a silicon wafer using the carrier. [Means to solve the problem]

In order to solve the above problems, the double-sided polishing carrier of the present invention is a double-sided polishing carrier that holds the silicon wafer when performing double-sided polishing on the silicon wafer, and is composed of a resin laminate containing a fiber base material. The roughly disc-shaped carrier body and the wafer holding hole formed in the carrier body; the fiber exposure rate on the main surface of the carrier body is less than 50%.

According to the present invention, when the fiber exposure rate on the main surface of the carrier body is less than 50%, the wear resistance can be improved. Therefore, productivity can be improved by reducing the frequency of carrier replacement, and the silicon wafer yield that meets the required flatness quality can be improved.

In the present invention, the flatness of the carrier body is preferably 5 μm or less. Accordingly, by using a carrier with a flatness of 5 μm or less and a fiber exposure rate of less than 50%, the wear resistance of the carrier can be ensured and the flatness quality of the wafer can be improved.

In the present invention, the thickness of the carrier body is preferably thinner than the thickness of the silicon wafer before grinding, and the thickness difference is 5~20 μm. Even if the thickness of the carrier gradually decreases due to the repeated use of the carrier in the double-sided grinding step, resulting in a situation where the difference between the thickness of the silicon wafer before grinding and the thickness of the carrier changes within the range of 5 to 20 μm, the fiber exposure rate of the carrier is still Keep it below 50%, thus preventing the vehicle wear rate from rapidly increasing.

Preferably, the above-mentioned resin laminated board has a multi-layer structure in which a plurality of composite sheets are made of a composite sheet containing a moistening resin as the above-mentioned fiber base material; the above-mentioned resin is epoxy, phenol or arylamine; the above-mentioned fiber base material is a glass fiber woven fabric , carbon fiber fabric or organic fiber fabric; the above-mentioned multi-layer structure has more than 3 layers.

Furthermore, the double-sided polishing method of the silicon wafer of the present invention includes: the step of preparing a double-sided polishing carrier; and disposing the above-mentioned double-sided polishing carrier between the upper fixed plate and the lower fixed plate to which the polishing cloth has been pasted. After loading the silicon wafer on the tool, while supplying slurry between the upper fixed plate and the lower fixed plate, the upper fixed plate and the lower fixed plate are rotated respectively, and the silicon wafer is ground on both sides; wherein , the above-mentioned carrier for double-sided polishing is equipped with: a substantially disc-shaped carrier body composed of a resin laminate containing a fiber base material, and a wafer holding hole formed in the above-mentioned carrier body; the main surface of the above-mentioned carrier body The fiber exposure rate is less than 50%.

According to the present invention, the rapid increase in the wear rate of the carrier caused by the increase in fiber exposure rate can be prevented, so that the service life of the carrier can be prolonged. Therefore, productivity can be improved by reducing the frequency of carrier replacement, and the silicon wafer yield that meets the required flatness quality can be improved.

The double-sided grinding method of the silicon wafer of the present invention preferably further includes: before the double-sided grinding step of the silicon wafer, the flatness of the carrier body is less than 5 μm, and the fiber exposure rate is less than 50 % method, a pre-grinding step is performed on the above-mentioned double-sided grinding carrier. Accordingly, by using a carrier with a flatness of 5 μm or less and a fiber exposure rate of less than 50%, the wear resistance of the carrier can be ensured and the flatness quality of the wafer can be improved.

In the present invention, in the step of pre-polishing the double-sided polishing carrier, it is preferable to adjust the thickness of the carrier body so that it is thinner than the pre-polishing thickness of the silicon wafer and the thickness difference is 5 to 10 μm. Furthermore, in the step of double-side polishing the silicon wafer, it is preferable to use the double-side polishing carrier whose thickness difference from the thickness before polishing of the silicon wafer is within a range of 20 μm or less. Even if the thickness of the carrier gradually decreases due to repeated use of the carrier in the double-sided polishing step, and the difference between the thickness of the silicon wafer before polishing and the thickness of the carrier changes within the range of 5~20 μm, the fiber exposure rate of the carrier still remains less than 10 μm. 50%, thus preventing a sudden increase in vehicle wear rate.

Furthermore, the double-side polishing device of the present invention is provided with: an upper fixed plate and a lower fixed plate to which polishing cloths are respectively attached, and a double-sided polishing carrier that is disposed between the upper fixed plate and the lower fixed plate and holds the silicon wafer. ; Wherein, the above-mentioned carrier for double-sided polishing is equipped with: a substantially disc-shaped carrier body composed of a resin laminate containing a fiber base material, and a wafer holding hole formed in the above-mentioned carrier body; the above-mentioned carrier body The fiber exposure rate of the main surface is less than 50%.

According to the present invention, the rapid increase in the wear rate of the carrier caused by the increase in fiber exposure rate can be prevented, so that the service life of the carrier can be prolonged. Therefore, productivity can be improved by reducing the frequency of carrier replacement, and the silicon wafer yield that meets the required flatness quality can be improved. [Effects of the invention]

According to the present invention, it is possible to provide a carrier for double-side polishing that has a longer life by improving wear resistance, and a method and device for double-side polishing of a silicon wafer using the carrier.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figures 1 and 2 show the structure of a double-sided polishing device according to an embodiment of the present invention. Figure 1 is a schematic cross-sectional view, and Figure 2 is a schematic plan view.

As shown in Figures 1 and 2, the double-sided grinding device 1 is provided with an upper fixed plate 2 and a lower fixed plate 3 that are opposed to each other in the up and down direction. The upper fixed plate 2 and the lower fixed plate 3 are respectively adhered to the grinding surfaces. Abrasive cloth 4. Examples of the polishing cloth 4 series include nonwoven fabrics containing urethane resin and foamed polyurethane pads.

A slurry supply device 5 for supplying slurry between the upper fixed plate 2 and the lower fixed plate 3 is provided above the upper fixed plate 2 . The slurry supply device 5 supplies slurry from the nozzle 6 inserted into the through hole 2 a of the upper fixed plate 2 . As the slurry system, an inorganic alkali aqueous solution containing colloidal silica can be used.

A sun gear 7 is provided at the center between the upper fixed plate 2 and the lower fixed plate 3, and an internal gear 8 is provided at the outer ring, forming a planetary gear type double-sided grinding device. The upper fixed plate 2, the lower fixed plate 3, the sun gear 7 and the internal gear 8 have the same central axis of rotation and can rotate independently of each other.

A plurality (three in this case) of double-sided polishing carriers 10 (hereinafter referred to as "carriers") are arranged between the upper fixed plate 2 and the lower fixed plate 3 . Each carrier 10 is arranged between the sun gear 7 and the internal gear 8 , and the outer ring gear system of the carrier 10 meshes with both the sun gear 7 and the internal gear 8 . When the upper fixed plate 2 and the lower fixed plate 3 are rotationally driven by a driving source (not shown), they rotate together with the sun gear 7 and the internal gear 8 . Thereby, the carrier 10 revolves around the sun gear 7 while rotating between the upper fixed plate 2 and the lower fixed plate 3 . At this time, since the silicon wafer W is sealed and held in the wafer holding hole provided in the carrier 10 , both surfaces are polished simultaneously using the upper and lower polishing cloths 4 . In addition, in the polishing step, the slurry is supplied from the nozzle 6 through the through hole 2a.

FIG. 3 shows a schematic plan view of the structure of the carrier 10 .

As shown in FIG. 3 , the carrier 10 is provided with: a carrier body 11 with a substantially disc-shaped appearance, a wafer holding hole 12 for holding the silicon wafer W (hereinafter referred to as the "holding hole"), and a The outer ring teeth 13 of the outer ring portion of the carrier body 11. The holding hole 12 is a circular opening formed by following one of the main surfaces (surface or top) of the carrier body 11 and penetrating to the other main surface (back or bottom). The diameter of the holding hole 12 is approximately equal to the diameter of the silicon wafer W. . Because the center position of the holding hole 12 deviates from the center position of the carrier 10 , the silicon wafer W in the holding hole 12 rotates eccentrically when the carrier 10 rotates. In this embodiment, the number of holding holes 12 formed in the carrier 10 is only one, but a plurality of holding holes 12 may also be provided.

FIG. 4 is a sectional view showing the cross-sectional structure of the resin laminated board constituting the carrier 10 .

As shown in Fig. 4, the carrier body 11 of the double-sided polishing carrier 10 is composed of a composite sheet 20 (FRP sheet) in which a fiber base material 21 is impregnated with a moistening resin 22, and a multi-layer structure resin laminate in which a plurality of sheets are overlapped. . The fiber base material 21 is preferably glass fiber woven fabric, carbon fiber woven fabric, etc. The resin 22 is preferably made of epoxy, phenol, arylamide, etc. The resin laminated board preferably has three or more layers of composite sheets 20 laminated, and preferably has a five-layer structure as shown in the figure.

In this embodiment, the fiber exposure rate on the main surface of the carrier 10 (carrier body 11) is less than 50%. That is, in the double-sided polishing step, the carrier 10 with a fiber exposure rate of less than 50% is used, and the carrier 10 with a fiber exposure rate of 50% or more is not used. The reason is that if the fiber exposure rate reaches more than 50%, the wear resistance of the vehicle will drop rapidly, resulting in a shortened vehicle life.

The fiber exposure rate of the carrier 10 used in the double-sided polishing step is ideally 0%. However, it is extremely difficult to regularly use the 10-series carrier with a fiber exposure rate of 0%. Generally, a resin laminated board is produced by integrating a plurality of composite sheets 20 by hot pressing. During hot pressing, the resin on the outermost surface will flow off, so even if the moisture content of the resin on the fiber base material is increased, the thickness of the resin on the outermost surface will not increase.

In addition, because the flatness of the new carrier is poor if it is not used immediately after completion, pre-grinding (pre-processing) of the new carrier is performed before actual use (see Figure 5). Specifically, pre-polishing is performed so that the difference from the pre-polishing thickness of the silicon wafer to be processed is 5 to 10 μm and the carrier flatness is 5 μm or less. If such pretreatment is performed, the fiber base material 21 will definitely be exposed on the main surface of the carrier 10, and judging from the amount of grinding, the fiber exposure rate will reach more than 50%. If the fiber exposure rate reaches more than 50%, the wear rate of the vehicle will increase rapidly, resulting in a shortened vehicle life.

However, in this embodiment, the fiber exposure rate of the main surface of the carrier used in the double-sided grinding step is maintained at less than 50%, and when pre-polishing is performed on a completely unused new carrier, it is natural that the fiber exposure rate immediately after the pre-polishing is performed. Needless to say, even when the lower limit of thickness is reached due to repeated use of the carrier, the grinding amount is adjusted to maintain the fiber exposure rate below 50%, thereby improving the wear resistance of the carrier and extending its life. .

Figure 6 shows a flow chart of a method for polishing both sides of a silicon wafer according to an embodiment of the present invention.

As shown in FIG. 6 , in the double-sided polishing method of the silicon wafer in this embodiment, an unused carrier 10 is first prepared (step S1 ). As described above, the carrier 10 is formed by hot-pressing a plurality of composite sheets 20 (for example, 5 sheets) to form a resin laminated board, and then performing punching processing to form a predetermined shape including the holding holes 12 and the outer ring teeth 13 . Make.

Next, in order to adjust the thickness of the carrier 10 and improve the flatness, pre-grinding (pre-processing) of the carrier is performed (step S2). The carrier is pre-polished using a device other than the wafer polishing device, and the carrier is polished using a slurry mixed with abrasive grains. In addition, during pre-polishing of the carrier, the polishing amount is set so that the fiber exposure rate is less than 50%. For example, the polishing process is performed by setting the polishing amount to a predetermined thickness (thickness upper limit) that is 5 to 10 μm thinner than the thickness before wafer polishing (for example, 785 μm). In this way, a carrier with a flatness adjusted to less than 5 μm and a fiber exposure rate of less than 50% in one set was obtained. Because the flatness of the carriers in one set is 5 μm or less, of course the flatness of each carrier is also 5 μm or less.

Next, the pre-polished carrier 10 is used to actually perform the double-side polishing step of the silicon wafer W (step S3). The silicon wafer to be processed is polished on both sides to achieve the target thickness and flatness. After the grinding process is completed, the silicon wafer W is taken out from the carrier and sent to the next processing step (single-side grinding step).

The carrier 10 can be reused and used repeatedly until it reaches the predetermined lower limit of thickness (steps S4N, S5, S6, S3). If the carrier is used in the double-side polishing step, the thickness of the carrier will also be reduced, and the carrier itself will also be worn through repeated wafer grinding. In particular, the wear of resin carriers is greater than that of metal carriers, so the number of times they can be reused is reduced, resulting in lower productivity.

In order to perform double-side polishing of the wafer W, a carrier 10 that is thinner than the wafer W must be used. However, when a carrier 10 that is very thin relative to the target thickness of the wafer W is used, the required flatness of the wafer cannot be ensured. Therefore, the lower limit value of the thickness of the carrier that can be used in the double-sided polishing step is set near the target thickness of the wafer, and the carriers that are too thin below the lower limit value are excluded (discarded) from being used (steps S4Y, S7) . The lower limit of the thickness of the carrier is, for example, set to the thickness before wafer polishing (for example, 785 μm) minus 20 μm.

Furthermore, vehicles with a fiber exposure rate of more than 50% on the main surface of the vehicle are also excluded from continuous use (steps S5Y, S7). Generally, the fiber exposure rate of a vehicle will increase with the number of uses. Vehicles with a fiber exposure rate of more than 50% will wear out very quickly. However, since the carrier of this embodiment is formed in such a way that even if the carrier is repeatedly used from the predetermined upper thickness limit to the lower thickness limit, the fiber exposure rate is always less than 50%, it is possible to suppress an increase in the wear rate of the carrier. In order to achieve long life.

As described above, the double-sided polishing method of the silicon wafer in this embodiment uses a double-sided polishing carrier made of a resin laminated board to perform double-sided polishing of the silicon wafer, and the fiber exposure rate on the main surface of the carrier is less than 100%. 50%, thus improving wear resistance and extending the life of the vehicle.

The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. Various changes can be made without departing from the gist of the present invention. Of course, these are also included in the scope of the present invention.

For example, in the above embodiment, a double-sided polishing device capable of loading three resin carriers is given as an example. However, the structure of the double-sided polishing device is not particularly limited, and various devices capable of using resin carriers can be used. In addition, the number of wafers that can be loaded in the carrier and the shape of the carrier are not particularly limited. [Example]

＜The relationship between carrier flatness and wafer flatness quality＞ Evaluate the impact of carrier flatness on wafer flatness quality. The double-sided grinding device uses a carrier that can load 5 pieces with a diameter of 500mm. The carrier system has a single wafer holding hole and can load one 300mm diameter wafer. The wafer system uses a p-type silicon single crystal wafer with a diameter of 300mm. As the polishing pad, a urethane polishing pad containing no abrasive grains is used. The slurry uses an inorganic alkali aqueous solution containing silica abrasive particles with a particle size of 60 to 110 nm and a pH of 11 to 12.

After the produced carriers are pre-polished in advance, the thickness of the carriers is measured using a laser displacement meter to determine the flatness of the carriers within a batch. The flatness of the carrier within a batch is measured from the position 1.01r (mm) away from the center of the carrier holding hole in the four directions up, down, left, and right, and is set as the measurement point.

The calculation method of the flatness of the carrier is shown in Figure 7. Set the direction from the center C of the holding hole toward the center of the carrier as the reference orientation (θ=0°), and calculate the thickness of four places near the outer ring in the four directions of θ=0°, 90°, 180°, and 270°. Measured values X ₁ , X ₂ , X ₃ , X ₄ . The distance between the center C of the holding hole 12 and the thickness measurement point is 1.01r (mm). r is the radius of the wafer holding hole.

From a total of 20 measured values obtained from 4 places on each _of the 5 carriers, the difference between the maximum value X _max and the _minimum value X _min ΔX = (μm).

Next, the ESFQR (Edge Site flatness Front reference least Square Range) of the double-sided polished silicon wafer is measured. The flatness evaluation index (site flatness) focuses on the edge of the wafer, where flatness is prone to deteriorate, and indicates the size of edge roll off. The flatness of the wafer edge is set to an annular outer ring area ranging from 2 to 32 mm (sector length 30 mm) from the outermost ring of the wafer, and is further divided equally in the circumferential direction to obtain unit areas (parts), and then Obtained based on each unit area (part). When measuring ESFQR, a wafer flatness measuring device (Wafer Sight manufactured by KLA-Tencor) was used. The measurement conditions are as follows: the measurement range is set to 296mm (excluding the outermost 2mm), the number of sectors (number of parts) when measuring the edge portion is set to 72, and the sector length is set to 30mm. The relationship between the flatness of the carrier and the EFSQR of the polished wafer is shown in Figure 8. In addition, ESFQR is the average of the measured values of 5 wafers in one batch.

As shown in Figure 8, it is found that if the flatness of the carrier is greater than 5 μm, the ESFQR of the wafer will deteriorate rapidly. This phenomenon can be considered to be due to the large variation in carrier thickness (flatness) within one batch, resulting in variations in the polishing state of the wafers within one batch.

＜The relationship between the fiber exposure rate of the carrier and the wear rate of the carrier＞ Secondly, the impact of the fiber exposure rate on the main surface of the carrier on the wear rate of the carrier was evaluated. The material of the carrier is composed of a five-layer structure resin laminate made of five overlapping sheets made of glass fiber cloth base material moistened with epoxy resin.

The fiber exposure rate on the main surface of the carrier is determined by randomly selecting 10 places from the outer ring area within 50mm of the outer ring end of the carrier wafer holding hole as observation places, and taking CCD microscope images of each observation place. The captured image is then binarized to calculate the area ratio of the fiber part. Figure 9(a) and (b) show an example of CCD microscope images of the carrier surface. Figure 9(a) shows the image before binarization processing, and Figure 9(b) shows the image after binarization processing. The image size of each measurement location is 2.8 × 2.1 (mm). The fiber exposure rate adjustment on the surface of the carrier is performed by adjusting the polishing amount in the step of pre-polishing the carrier to adjust the thickness or flatness of the carrier.

The carrier wear rate is determined by loading a dummy silicon wafer that is slightly thinner than the carrier thickness and using a silicon wafer polishing slurry containing colloidal silicon dioxide to polish both sides of the carrier. From this point on, the carrier thickness per unit time The reduction (thickness difference before and after grinding) is calculated. The results are shown in Figure 10. In Figure 10, the vertical axis carrier wear rate is the value when the fiber exposure rate is 90%, and is the relative value when the reference value is 100.

It can be seen from Figure 10 that when the fiber exposure rate is below 42%, the carrier wear rate is a low value below 27. However, when the fiber exposure rate is around 50%, the carrier wear rate increases rapidly. When the fiber exposure rate reaches more than 60%, At this time, the vehicle wear rate is close to about 100. On the contrary, it is found that the carrier wear rate starts to decrease sharply when the fiber exposure rate is less than 60%. When the fiber exposure rate is 50%, the carrier wear rate is less than half of the carrier wear rate when the fiber exposure rate is 90%. Based on this, the reason why the carrier is prone to wear when the fiber exposure rate reaches 50% or more is considered to be due to the corrosion of the exposed glass fiber portion on the surface of the carrier by the highly alkaline polishing slurry.

＜Relationship between the fiber exposure rate of the carrier and the number of wafers processed＞ The number of wafers processed when the carrier is reused from the upper limit to the lower limit is evaluated for a carrier thickness specification set by considering a certain wafer thickness and flatness specification. The results are shown in Figure 11.

It can be seen from Figure 11 that when the fiber exposure rate is less than 42%, the number of wafers processed is around 400, but when the fiber exposure rate is 48%, the number of wafers processed is reduced to 250. When the fiber exposure rate is 48%, the number of wafers processed is reduced to 250. When it reaches more than 60%, the number of wafers processed is reduced to about 100.

The fiber exposure rate of the carrier affects the wear rate of the carrier as mentioned above. Therefore, it is best to keep the fiber exposure rate less than 50%. This can be confirmed to extend the carrier life.

1:Double-sided grinding device 2: Set the price 2a:Through hole 3: Make a final decision 4:Abrasive cloth 5: Slurry supply device 6:Nozzle 7:Sun gear 8: Internal gear 10: Carrier for double-sided grinding 11: Vehicle body 12: Wafer holding hole 13:Outer ring teeth 20: Composite sheet 20a: Composite sheet 20b: Composite sheet 21: Fiber base material 22:Resin W: silicon wafer

Figure 1 is a schematic cross-sectional view of the structure of a manufacturing device according to an embodiment of the present invention; Figure 2 is a schematic plan view of the structure of a single crystal manufacturing apparatus according to an embodiment of the present invention; Figure 3 is a schematic plan view of the vehicle; Figure 4 is a cross-sectional structural cross-sectional view of the resin laminated board constituting the carrier; Figure 5 is a schematic diagram illustrating the pre-grinding (pre-processing) of the carrier; Figure 6 is a flow chart illustrating a method for polishing both sides of a silicon wafer according to an embodiment of the present invention; Figure 7 is a schematic diagram illustrating the flatness calculation method of the vehicle; Figure 8 is a graph showing the relationship between carrier flatness and wafer outer ring flatness (ESFQR); In Figure 9, Figures 9(a) and (b) are CCD microscope images of the carrier surface, Figure 9(a) is the image before binarization processing, and Figure 9(b) is the image after binarization processing; Figure 10 is a graph showing the relationship between fiber exposure rate and wear rate of the carrier; and Figure 11 is a graph showing the relationship between carrier fiber exposure rate and the number of wafers processed.

10: Carrier for double-sided grinding

11: Vehicle body

12: Wafer holding hole

13:Outer ring teeth

Claims (9)

A carrier for double-sided polishing, which holds the silicon wafer when double-sided polishing is performed on the silicon wafer, and is provided with: A slightly disc-shaped carrier body, which is composed of resin laminates containing fiber substrates; and A wafer holding hole is formed in the above-mentioned carrier body; Among them, the fiber exposure rate on the main surface of the carrier body is less than 50%. A carrier for double-sided polishing as claimed in claim 1, wherein the flatness of the carrier body is 5 μm or less. Such as claim 2 for a carrier for double-sided polishing, wherein the thickness of the carrier body is thinner than the thickness of the silicon wafer before grinding, and the thickness difference is 5~20 μm. The carrier for double-sided polishing according to any one of claims 1 to 3, wherein the resin laminated board has a multi-layer structure in which a plurality of composite sheets are overlapped by making the fiber base material contain moistening resin; The above resin is epoxy, phenol or arylamide; The above-mentioned fiber substrate is glass fiber woven fabric, carbon fiber woven fabric or organic fiber woven fabric; The above-mentioned multi-layer structure has more than 3 layers. A method for grinding both sides of a silicon wafer, including: Steps for preparing a carrier for double-sided grinding; and After loading the silicon wafers on the above-mentioned double-sided polishing carrier arranged between the upper fixed plate and the lower fixed plate with polishing cloths respectively pasted thereon, the slurry is supplied between the upper fixed plate and the lower fixed plate while using them respectively. The above-mentioned upper fixed plate and the above-mentioned lower fixed plate rotate, and the step of grinding both sides of the above-mentioned silicon wafer is performed; Among them, the above-mentioned double-sided grinding carrier system includes: a slightly disk-shaped carrier body composed of a resin laminated board containing a fiber base material, and A wafer holding hole formed in the above-mentioned carrier body; Furthermore, the fiber exposure rate on the main surface of the carrier body is less than 50%. The method of double-sided grinding of silicon wafers as claimed in claim 5, wherein before the step of double-sided grinding of the silicon wafer, the method further includes: the flatness of the carrier body is below 5 μm, and the fiber exposure rate is If it is less than 50%, perform a pre-grinding step on the above-mentioned double-sided grinding carrier. The double-sided polishing method of claim 6, wherein the step of pre-polishing the double-sided polishing carrier is adjusted in such a way that it is thinner than the pre-polishing thickness of the silicon wafer and the thickness difference becomes 5 to 10 μm. The thickness of the vehicle body. The double-side polishing method of claim 7, wherein the step of double-side polishing the silicon wafer uses the double-side polishing carrier whose thickness difference from the thickness before polishing of the silicon wafer is within a range of 20 μm or less. A double-sided grinding device, the system has: The upper fixed plate and the lower fixed plate have been pasted with grinding cloth and A carrier for double-sided polishing, which is arranged between the above-mentioned upper fixed plate and the above-mentioned lower fixed plate and holds the silicon wafer; Among them, the above-mentioned double-sided grinding carrier system includes: a slightly disk-shaped carrier body composed of a resin laminated board containing a fiber base material, and A wafer holding hole formed in the above-mentioned carrier body; Furthermore, the fiber exposure rate on the main surface of the carrier body is less than 50%.

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