TW201943496A - Carrier, method of manufacturing carrier, method of evaluating carrier, and method of polishing semiconductor wafer - Google Patents

Abstract

A carrier, which is capable of facilitating to obtain a semiconductor wafer having a high flatness in the outer peripheral portion after double-side polishing, a method of manufacturing the carrier, a method of evaluating a carrier, and a method of polishing a semiconductor wafer are provided. In a carrier for double-sided polishing, which has a holding hole for holding a semiconductor wafer, the difference between the thickness of the carrier at the position of the inner wall defining the holding hole and the thickness of the carrier from the inner wall to a position 6 mm radially outside of the holding hole is 1 [mu]m or less.

Description

Carrier, manufacturing method of carrier, carrier evaluation method, and semiconductor wafer polishing method

The present invention relates to a carrier, a method for manufacturing the carrier, a method for evaluating the carrier, and a method for polishing a semiconductor wafer.

In the manufacture of semiconductor wafers used as the substrate of semiconductor devices, in order to obtain higher flatness and surface roughness, a pair of pressure plates attached with polishing pads are used to sandwich the semiconductor wafer and supply polishing slurry at the same time. In order to perform a double-side polishing step of simultaneously polishing both sides of a semiconductor wafer. At this time, the semiconductor wafer is held by a carrier.

The carrier is mainly a carrier made of metal such as stainless steel or titanium. FIG. 1 illustrates an example of a metal carrier (for example, see Patent Document 1). The carrier 1 shown in this figure is provided with a metal portion 11 as a carrier body, so that a semiconductor wafer can be held in a holding hole 12 provided in the metal portion 11.

When the semiconductor wafer is held in the holding hole 12 of the metal portion 11 and double-sided polishing is performed, if the outer peripheral portion of the semiconductor wafer contacts the inner wall 12a defining the holding hole 12, the semiconductor wafer may be damaged. Doubts. Therefore, an annular resin portion 13 made of a resin softer than metal is provided along the inner wall 12 a of the holding hole 12 of the metal portion 11 to protect the outer peripheral portion of the semiconductor wafer.

Furthermore, unlike the metal carrier 1 shown in FIG. 1, as shown in FIG. 2, a resin carrier 2 made of a resin in which the carrier body 21 is made is also proposed to hold the semiconductor wafer in a holding state. In the hole 22 (see, for example, Patent Document 2).

For example, the carrier described above can be manufactured by the method described below. First, in the case of a metal carrier 1, for example, after performing laser processing or milling processing on a stainless steel plate, a step of removing deformation by heat treatment is performed to process the metal portion 11 into the shape of the carrier, and The wafer holding hole 12 is provided.

On the other hand, the resin portion 13 can be obtained, for example, by processing a sheet material of aromatic polyamide to obtain a ring-shaped member. At this time, the thickness of the ring-shaped member is made larger than that of the metal portion 11, and then the ring-shaped member is embedded along the inner wall 12 a of the holding hole 12, and the ring-shaped member is polished by grinding to make it The thickness may match the thickness of the metal portion 11. In this way, the carrier 1 made of metal can be manufactured.

In the case of the resin-made carrier 2, for example, a laminated board obtained by immersing a resin in carbon fibers is processed into the shape of the carrier, and then the holding holes 22 are formed. Then, the thickness can be adjusted by lapping or polishing to manufacture a resin-made carrier 2.

The semiconductor wafer to be polished, such as a silicon wafer, is held in a holding hole of a carrier manufactured as described above, and the carrier is sandwiched between an upper platen and a lower platen of a double-sided grinding equipment (not shown). Meanwhile, by rotating the upper platen and the lower platen while supplying the slurry, both sides of the semiconductor wafer can be polished.
[Prior Art Literature]
[Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 5648623
[Patent Document 2] Japanese Patent Laid-Open No. Showa 58-143954

[Problems to be Solved by the Invention]

By the way, in recent years, with the development of miniaturization and high integration of semiconductor devices, semiconductor wafers need to have extremely high flatness. In addition, the device formation area also expands year by year on the radially outer side of the wafer, and the outer peripheral portion of the wafer also requires high flatness.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a carrier, a method for manufacturing the carrier, a method for evaluating the carrier, and a method for polishing a semiconductor wafer. Degrees of semiconductor wafers.
[Means for solving problems]

The gist of the present invention for solving the above problems is as follows.
(1) A carrier having a thickness for defining a position of an inner wall of the holding hole in the carrier, and a carrier for a double-side polishing having a holding hole for holding a semiconductor wafer, and the carrier The difference in thickness from the inner wall to the position radially outside 6 mm of the holding hole is 1 μm or less.

(2) The carrier according to (1), wherein the carrier includes a metal part as a main body of the carrier, and is disposed along an inner wall defining an opening portion provided in the metal part for protecting the semiconductor crystal. A circular resin portion having a circular outer peripheral portion, and an opening portion provided in the resin portion constitutes the aforementioned holding hole.

(3) The carrier according to (1), wherein the aforementioned carrier is made of resin.

(4) A method for manufacturing a carrier, which is the method for manufacturing a carrier according to any one of (1) to (3), which comprises processing an original plate made of a predetermined material into a predetermined shape to The processing steps of forming the intermediate structure of the carrier, and adjusting the intermediate structure of the carrier to a predetermined thickness and flatness to obtain a thickness adjustment step of the carrier. The aforementioned thickness adjustment step includes a grinding process step and a grinding process step. The processing amount of the grinding processing step is larger than that of the aforementioned grinding processing step.

(5) The method for manufacturing a vehicle according to (4), wherein the thickness of the intermediate structure of the vehicle before the grinding process step is greater than the thickness of the intermediate structure of the vehicle after the grinding process step 10 μm or more.

(6) The method for manufacturing a carrier according to (4) or (5), wherein the processing amount in the grinding step is 10 μm or less.

(7) An evaluation method of a carrier, which is an evaluation method of a carrier having a holding hole for holding a semiconductor wafer and applied to a double-side polishing step of the semiconductor wafer, wherein the holding hole is defined in the carrier The thickness of the inner wall of the carrier and the thickness of the carrier from the inner wall to a position radially outside 6 mm of the holding hole were measured, and it was judged that the quality was good when the difference between the two was 1 μm or less.

(8) The method for evaluating a vehicle according to (7), wherein the vehicle includes a metal portion as a vehicle body, and is provided along an inner wall of the retaining hole defined in the metal portion for use in the vehicle. The annular resin portion of the outer peripheral portion of the semiconductor wafer is protected.

(9) The method for evaluating a vehicle according to (7), wherein the vehicle is made of resin.

(10) A method for polishing a semiconductor wafer using the carrier according to any one of (1) to (3), and the carrier according to any one of (4) to (6) The carrier manufactured by the manufacturing method, or a carrier judged to be of good quality according to the carrier evaluation method described in any one of (7) to (9), performs double-side polishing of the semiconductor wafer.

(11) The method for polishing a semiconductor wafer according to (10), wherein after performing double-side polishing, the thickness of the inner wall of the holding hole is defined in the carrier, and from the inner wall to the aforementioned in the carrier. The thickness at a position 6 mm radially outward of the holding hole is measured, and if the difference between the two exceeds 1 μm, it is replaced with another carrier having a thickness difference of 1 μm or less for the next double-side polishing.

(12) The method for polishing a semiconductor wafer according to (10)) or (11), wherein the semiconductor wafer is a silicon wafer.
[Effect of the present invention]

According to the present invention, a semiconductor wafer having a high flatness in the outer peripheral portion after double-side polishing can be obtained.

(vehicle)
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The carrier according to the present invention is a carrier for double-side polishing having a holding hole for holding a semiconductor wafer. Here, the difference between the thickness of the position of the inner wall of the holding hole in the carrier and the position of 6 mm from the inner wall to the radially outer side of the holding hole in the carrier (hereinafter also referred to as "holding hole of the carrier" The amount of collapse '') is 1 μm or less.

In order to obtain a semiconductor wafer having a high flatness in the outer peripheral portion after double-sided polishing, the inventors performed double-sided polishing on the semiconductor wafer using various carriers, and checked the flatness of the outer peripheral portion of the polished semiconductor wafer. As a result, it can be found that, as shown in FIG. 3, the thickness of the carrier in the peripheral area of the holding hole (the area shown by α in FIG. 3) is reduced, that is, “collapse”, and the peripheral portion of the wafer after double-side polishing The degree of flatness is closely related.

That is, when a semiconductor wafer is double-sidedly polished using a carrier having a low degree of collapse in the peripheral area of the holding hole, the flatness value of the outer peripheral portion of the wafer is small, compared with that in the periphery of the holding hole. In the case of a carrier having a high degree of area collapse, the flatness value of the peripheral portion of the wafer becomes large.

It is considered that this is because when a carrier with a high degree of collapse in the peripheral area of the holding hole is used for double-side polishing, the polishing pad attached to the upper platen or the lower platen enters the collapsed portion around the holding hole in the carrier. So that the peripheral portion of the wafer is excessively polished. Therefore, in order to obtain a semiconductor wafer having high flatness in the outer peripheral portion after double-side polishing, it is considered that it is important to perform double-side polishing using a carrier having a low degree of collapse in the thickness around the hole.

Based on the above speculations, the present inventors have conducted intensive studies on conditions under which a semiconductor wafer having a high flatness in the outer peripheral portion after double-side polishing can be obtained. As a result, it was found that when the thickness of the position defining the inner wall of the holding hole in the carrier and the thickness of the carrier from the inner wall to the position outside 6 mm in the radial direction of the holding hole were 1 μm or less, A semiconductor wafer with extremely high flatness in the outer peripheral portion after double-sided polishing has completed the present invention.

As described above, the carrier for double-side polishing according to the present invention is characterized in that the degree of collapse of the thickness of the peripheral area of the holding hole is adjusted to be within a predetermined range, and other structures can appropriately use the previously used structures. Known structure.

For example, as the carrier of the present invention, any one of a metal carrier 1 as shown in FIG. 1 and a resin carrier 2 as shown in FIG. 2 may be used, and the carrier 1 is provided as a carrier. A metal portion 11 of the main body and an annular resin portion 13 provided along an inner wall 12a defining an opening portion provided in the metal portion 11 to protect the outer peripheral portion of the semiconductor wafer W are provided on the resin. The opening portion of the portion 13 constitutes a holding hole 12. When the carrier is a metal carrier 1, the thickness of the position of the inner wall 13a of the resin portion 13 in the carrier 1 and the position of 6 mm from the inner wall 13a to the radially outer side of the holding hole 12 in the carrier 1 The difference in thickness (the amount of collapse of the holding hole of the carrier) is 1 μm or less. In addition, in the ring-shaped resin portion 13 described in Japanese Patent Laid-Open No. 2003-109925, in order to prevent the resin portion 13 from rotating to a portion contacting the inner wall 12a of the holding hole 12 of the metal portion 11, There is a non-circular portion protruding from the metal portion 11, but the amount of collapse of the holding hole of the carrier is evaluated at a position where the non-circular portion does not exist.

In the case of a metal carrier 1, the metal portion 11 may be made of a metal such as stainless steel or titanium, and a laser processing or milling process is performed on a sheet of this metal to process the shape of the carrier. The step of removing the deformation is performed by a heat treatment to form the metal portion 11.

In addition, the resin portion 13 may be made of a general resin, and aromatic polyamines, nylon-based polyamines (PA), polyacetals (POM), polyvinyl chloride (PVC), and polypropylene (PP) may be used. ), Polyvinylidene fluoride (PVDF) and fluorocarbon resin (PFA / ETFE), etc.

The resin portion 13 preferably contains glass fibers. This can improve the durability of the resin member. The content of the glass fiber is calculated based on the volume ratio, and preferably 10 to 60%.

Furthermore, when the carrier is a resin carrier 2 as shown in FIG. 2, the carrier body may be made of resin such as epoxy resin, phenol, polyimide, polyimide, glass fiber, and carbon fiber. And fiber-reinforced plastics formed by combining reinforcing fibers such as aromatic polyamide fibers. Furthermore, it may be a carrier coated with diamond (DLC). Among them, considering the advantages of pollution and cost, it is better to use a composite material of epoxy resin and glass fiber. In addition, it is preferable that the resin portion 13 which is the same as the carrier 1 made of metal contains glass fiber, and the content of the glass fiber is preferably 10 to 60% by volume ratio.

In addition, a non-contact sensor such as a laser displacement meter or a capacitance sensor can be used to measure the thickness of the carrier along the radial direction of the carrier, thereby obtaining the thickness distribution of the carrier as shown in FIG. 4 curve. Then, the amount of collapse of the holding hole of the carrier can be obtained from the obtained thickness distribution curve.

In this way, according to the carrier for double-side polishing of the present invention, the flatness of the outer peripheral portion of the semiconductor wafer after double-side polishing can be improved. Specifically, the maximum value of ESFQR can be set to 70 nm or less.
In addition, the so-called ESFQR (Edge flatness metric, Sector based, Front surface referenced, Site Front least sQuaresRange) is an index indicating the flatness measured on the SFQR in a fan-shaped area formed on the outer peripheral portion of the wafer, and A smaller value means higher flatness.

(Manufacturing method of vehicle)
Next, the manufacturing method of the carrier based on this invention is demonstrated. The manufacturing method of a carrier according to the present invention is the above-mentioned manufacturing method of a carrier according to the present invention, and includes processing steps (steps) of processing an original plate made of a predetermined material into a predetermined shape to form an intermediate structure of the vehicle. S1), and adjusting the intermediate structure of the carrier to a predetermined thickness and flatness to obtain a thickness adjustment step of the carrier (step S2). Here, the thickness adjustment step includes a grinding processing step and a grinding processing step, and the processing amount of the grinding processing step is greater than the processing amount of the grinding processing step.

As described above, the present inventors have found that the degree of the carrier collapse in the peripheral region of the holding hole has a great influence on the flatness of the outer peripheral portion of the wafer after double-side polishing, and also found that by using the carrier By holding the carrier in which the amount of collapse of the hole is 1 μm or less, a semiconductor wafer having an extremely high flatness in the outer peripheral portion after double-side polishing can be obtained.

However, as a result of intensive research by the present inventors, when the carrier is manufactured by a general method, the degree of collapse of the carrier in the peripheral region of the holding hole becomes large, and the amount of collapse of the holding hole of the carrier is Carriers below 1 μm are by no means easy. Therefore, first, the present inventors conducted intensive research on the reason why the degree of collapse of the carrier in the peripheral region of the holding hole becomes large. As a result, it was found that the reason why the degree of collapse of the carrier became larger was that when the thickness of the carrier was adjusted by the grinding process using a double-sided grinding device, the polishing pads attached to the upper and lower platens entered the holding holes. Inside so that the peripheral area of the holding hole of the carrier becomes rounded.

According to the results of further research by the present inventors, when a double-side polishing apparatus is used without a polishing pad, the degree of collapse of the carrier around the holding hole is small. Therefore, in order to suppress the collapse of the carrier in the peripheral region of the holding hole, it is preferable to adjust the thickness of the carrier by grinding. However, there is a problem that the surface of the carrier after grinding is rough.

Therefore, the present inventors have conducted intensive research on how to manufacture a carrier that can suppress the collapse of the peripheral region of the holding hole and that the amount of the holding hole of the carrier is 1 μm or less. As a result, it was found that the thickness adjustment step of the carrier includes a grinding processing step and a grinding step, and the processing amount of the grinding processing step is set to be larger than that of the grinding processing step, which has a very significant effect.

In addition, in the present invention, the "polishing process step" refers to a step of processing using a carrier having a double-side polishing apparatus including an upper platen and a lower platen, and a polishing pad is attached to these platens. "Machining step" refers to the step of processing using a double-sided grinding device, and the two steps are clearly distinguished. The processing amount refers to a change in the thickness of the center of the carrier. In addition, the polishing processing step may be performed a plurality of times, and the processing amount of the polishing processing step means the total processing amount of the multiple polishing processing steps. Each step is described below.

First, in step S1, the original plate constituting the main body of the vehicle is processed into a predetermined shape to form an intermediate structure of the vehicle (processing step). In the case where the carrier is a metal carrier 1 shown in FIG. 1, first, a plate such as stainless steel or titanium is cut into an appropriate size according to the size of the final carrier, and processed into metal as the carrier body. Section 11.

In addition, the method of forming the resin portion 13 can be divided into two methods of forming the resin portion 13 separately from the metal portion 11 and two methods of injection molding into the holding hole 12 of the metal portion 11. In the case where it is formed separately from the metal portion 11, for example, a resin material made of epoxy resin is prepared and adjusted to a desired thickness by a grinding process or a grinding process, and then cut into a ring having an appropriate size and thickness. Shaped parts. Thereafter, the above-mentioned ring-shaped member may be subjected to a milling process and burrs may be removed to form the resin portion 13. The obtained resin portion 13 is embedded therein along the inner wall 12 a of the holding hole 12 of the metal portion 11. In this way, the intermediate structure of the vehicle can be obtained.

In addition, in a case where the resin portion 13 is formed by injection molding, the metal portion 11 is placed in a mold and sandwiched in the mold. Next, the resin flows radially from the center of the holding hole 12 and is formed by cooling. After that, excess resin was removed and chamfered. In this way, the resin portion 13 can be formed in the holding hole 12 by injection molding. Therefore, an intermediate structure of the vehicle can be obtained.

When the carrier is a resin carrier 2 shown in FIG. 2, for example, a plate made of epoxy resin containing glass fiber is cut into an appropriate size according to the size of the final carrier, and The shape of the vehicle is processed to obtain the intermediate structure of the vehicle.

Next, in step S2, the intermediate structure of the vehicle obtained in step S1 is adjusted to a predetermined thickness and flatness to obtain a vehicle (thickness adjustment step). First, by a grinding process using a double-sided grinding device, both sides of the intermediate structure of the carrier are ground with a predetermined processing amount.

Next, both sides of the intermediate structure subjected to the grinding process are ground using a double-side grinding apparatus. At this time, it is important that the processing amount of the grinding processing step is larger than that of the grinding processing step. This makes it possible to obtain a carrier in which the holding hole of the carrier has a collapse amount of 1 μm or less.

In addition, by simultaneously performing the grinding process on the intermediate structure of the plurality of carriers (for example, the intermediate structure of five carriers for a 300 mm wafer), the thickness of the intermediate structures of the plurality of carriers can be the same. , Can also achieve the effect of eliminating the scar on the surface of the intermediate structure of the vehicle.

In the case where a plurality of grinding steps are performed, the rough grinding step may be performed after the first rough grinding step, and the rough grinding step may be repeated after the second and subsequent times. In addition, it is preferable to perform a thickness measurement step after the first rough grinding process step, and perform a classification step based on the measured thickness to reduce variation in the thickness of the intermediate structure of the carrier, and then further perform a second grinding process. step,. By adding such a thickness measurement step and a classification step, it is possible to make the thickness of the intermediate structure of a plurality of carriers placed in the double-side polishing device at the same time more uniform and more accurate.

In this way, as the specific shape of the holding hole of the carrier, it can be obtained that the lower end portion of the holding hole of the carrier is 90 degrees (right angle ± 1 degree), and the degree of collapse of the holding hole of the carrier on the surface side exceeds 0 μm and is A shape of 1 μm or less.

In addition, the thickness of the intermediate structure of the carrier before the grinding processing step is preferably greater than the thickness of the intermediate structure of the carrier by 10 μm or more after the grinding processing step. In this way, it is possible to further suppress the carrier collapse around the holding hole, and to further improve the flatness of the outer peripheral portion of the semiconductor wafer after double-side polishing.

The processing amount in the polishing process step is preferably 10 μm or less. In this way, it is possible to further suppress the carrier collapse around the holding hole, and to further improve the flatness of the outer peripheral portion of the semiconductor wafer after double-side polishing.

(Vehicle evaluation method)
Next, a method for evaluating a vehicle according to the present invention will be described. An evaluation method of a carrier according to the present invention is an evaluation method of a carrier having a holding hole for holding a semiconductor wafer and applied to double-side polishing of the semiconductor wafer. Here, the thickness of the inner wall defining the holding hole in the carrier and the thickness from the inner wall to a position outside the radial direction of 6 mm from the holding hole were measured. The difference between the two (the collapse of the holding hole of the carrier When the amount) is 1 μm or less, it is determined that the quality is good.

As described above, the present inventors have found that by using a carrier in which the holding hole of the carrier has a collapse amount of 1 μm or less, a semiconductor wafer having an extremely high flatness in the outer peripheral portion after double-side polishing can be obtained. According to the evaluation method of the vehicle according to the present invention, it can be judged whether the vehicle meets the above requirements.

The thickness of the aforementioned carrier can be measured by using a non-contact sensor such as a laser displacement meter or a capacitive sensor.

Furthermore, as the vehicle to be evaluated, any one of the metal vehicle 1 shown in FIG. 1 and the resin vehicle shown in FIG. 2 can be evaluated.

(Semiconductor wafer polishing method)
Next, a method for polishing a semiconductor wafer according to the present invention will be described. According to the method for polishing a semiconductor wafer according to the present invention, the carrier according to the present invention is used, a carrier manufactured by the carrier manufacturing method according to the present invention, or an evaluation method of the carrier according to the present invention. The carrier judged to be of good quality was subjected to double-side polishing of the semiconductor wafer.

The double-side polishing itself can be performed using a conventionally known method. The semiconductor wafer to be polished is held in the holding hole of the carrier, and the carrier is sandwiched between the upper and lower pressing plates of the double-side polishing equipment (not shown). Then, by rotating the upper and lower platens while supplying the slurry, both sides of the semiconductor wafer can be polished. In this way, a semiconductor wafer having a high flatness in the outer peripheral portion after double-side polishing can be obtained.

The semiconductor wafer to be polished is not particularly limited, and may be, for example, a silicon wafer.

In addition, during manufacturing, even if the holding hole of the carrier collapses to 1 μm or less, when the double-sided polishing of the semiconductor wafer is continuously repeated, the peripheral area of the holding hole of the carrier may be polished by the double-sided polishing equipment. When the pad is ground, the degree of collapse is increased. When the double-side polishing is performed in a state where the difference in thickness of the carrier exceeds 1 μm, the flatness of the outer peripheral portion of the wafer is reduced.

Therefore, after double-sided polishing, determine whether the amount of the holding hole of the carrier is 1 μm or less. If it exceeds 1 μm, replace the carrier with a thickness of 1 μm or less for the next double-sided polishing Better. In this way, even if the double-sided polishing of the semiconductor wafer is repeated, a semiconductor wafer having a high flatness in the outer peripheral portion can be continuously obtained.
[Example]

Hereinafter, examples of the present invention will be specifically described, but the present invention is not limited to the examples.

> Manufacture of Vehicles>
(Inventive Example 1)
Based on the target set thickness of a 300mm wafer, a carrier with a final thickness set between 760 and 820 μm is manufactured as described below. First, an original plate made of epoxy resin containing glass fibers is cut and processed into the shape of a carrier to obtain an intermediate structure of the carrier. Next, in order to achieve the purpose of improving the dimensional accuracy and shape accuracy, a double-side grinding device is used to perform the grinding treatment, in which abrasive particles with a particle size of # 200 are used as a polishing liquid, and the load L is set to about 250 g / cm ² The sun gear and the internal gear are rotated to grind both sides of the dummy silicon substrate and the intermediate structure of the carrier accommodated in the carrier. Then, the intermediate structure of the carrier was ground to a grinding processing amount of 26 μm, and then washed. Then, according to a known technique, primary polishing (rough polishing) and secondary polishing (fine polishing) are performed by a double-side polishing apparatus to perform double-side polishing with a polishing processing amount of only 15 μm. The total processing amount was 41 μm.

(Inventive Example 2)
Similarly to Invention Example 1, a carrier having a final thickness was manufactured. However, the processing amount in the grinding processing step is 32 μm, the processing amount in the grinding processing step is 9 μm, and the total processing amount is 41 μm. The other conditions are exactly the same as those of Invention Example 1.

(Inventive Example 3)
Similarly to Invention Example 1, a carrier having a final thickness was manufactured. However, the manufactured vehicle includes a metal portion as a vehicle body and a ring-shaped resin portion (insertion member). Specifically, an original plate made of an aromatic polyamide resin is cut and processed into a ring shape to fit into the metal of the carrier body. In order to prevent the thickness of the metal part of the carrier body from being reduced in the grinding process step and the grinding process step, the thickness of the metal part is set to be 40 μm thinner than the thickness of the insert member. Then, in the same manner as in Inventive Example 1, a double-side grinding process and a double-side grinding process were performed. After processing, the thickness of the metal portion and the insert member as the carrier body becomes the same.

(Comparative Example 1)
Similarly to Invention Example 1, a carrier having a final thickness was manufactured. However, the thickness of the original plate was selected to be 20 μm thinner than that of Invention Example 1. No grinding process step was performed. The processing amount in the grinding process step was set to 21 μm, and the total processing amount was 21 μm. The other conditions are exactly the same as those of Invention Example 1.

(Comparative Example 2)
A vehicle was manufactured in the same manner as in Comparative Example 1. However, the thickness of the original plate was selected to be 20 μm thinner than that of Invention Example 1, the processing amount of polishing was set to 11 μm, and the total processing amount was 11 μm. Other conditions are exactly the same as those of Comparative Example 1.

> Evaluation of the amount of collapse of the holding hole of the vehicle>
For the carriers manufactured according to Invention Examples 1 to 3 and Comparative Examples 1 and 2, a laser displacement meter manufactured by Keyence was used to measure the amount of collapse of the holding holes of the carrier. As a result, the amount of collapse of the holding hole of the carrier was 1.0 μm in Inventive Example 1, 0.2 μm in Inventive Example 2, 1.0 μm in Inventive Example 3, and 1.9 μm in Comparative Example 1. In Example 2, it was 1.2 μm. The results obtained are shown in Figure 5.

Referring to FIG. 5, it can be seen from the comparison between Invention Examples 1 to 3 and Comparative Examples 1 and 2 that compared with Comparative Examples 1 and 2 in which the thickness of the carrier is adjusted only by the grinding process step, In Invention Examples 1 to 3 in which the thickness of the carrier is adjusted by a combination of a cutting process and a grinding process, the value of the amount of collapse of the holding hole of the carrier is small, and a carrier having a low degree of collapse in the peripheral region of the holding hole can be obtained . Furthermore, it can be seen from the comparison between Inventive Example 1 and Inventive Example 2 that in Comparative Example 1 in which the processing amount of the grinding process step is large, the value of the amount of the holding hole of the carrier is large, and the holding hole can be obtained Vehicles with a high degree of collapse in the surrounding area.

> Evaluation of the flatness of the peripheral portion of the wafer>
Using the carriers manufactured in Invention Examples 1 to 3 and Comparative Examples 1 and 2, a silicon wafer (diameter: 300 mm) was polished on both sides. Next, the flatness measuring device (manufactured by KLA-Tencor: WaferSight) was used to measure the ESFQR of the silicon wafer after double-side polishing. Specifically, the measurement exclusion region (edge exclusion region) is set to 1 mm, and the entire circumference of the wafer is divided into 72 points at intervals of 5 degrees, and the measurement is performed in a fan-shaped region whose length is 30 mm. The measured maximum value of ESFQR is shown in Figure 6.

As shown in FIG. 6, it is clear from the comparison between Invention Examples 1 to 3 and Comparative Examples 1 and 2 that Invention Example 1 is used to adjust the thickness of the carrier by using a combination of a grinding process step and a grinding process step. ～ 3, the maximum value of ESFQR after double-side polishing is 70 nm or less, and high flatness of the outer peripheral portion of the wafer can be achieved. Furthermore, it can be known from the comparison between Inventive Example 1 and Inventive Example 2 that by setting the polishing amount in the polishing process step to 10 μm or less, the maximum value of ESFQR can be further reduced.
[Industrial profitability]

According to the present invention, since a semiconductor wafer having a high flatness in the outer peripheral portion after double-side polishing can be obtained, it is beneficial to the semiconductor wafer manufacturing industry.

1, 2‧‧‧ vehicles

11‧‧‧ metal parts

12, 22‧‧‧ holding holes

12a, 13a, 21a ‧‧‧ inner wall

13‧‧‧ resin part

21‧‧‧ vehicle body

FIG. 1 is a schematic diagram showing an example of a metal carrier.

Fig. 2 is a schematic diagram showing an example of a resin-made carrier.

3 is a schematic diagram showing a positional relationship among a polishing pad, a semiconductor wafer, and a carrier in a double-side polishing step.

FIG. 4 is a diagram showing an example of a thickness distribution curve of a vehicle.

[Fig. 5] The difference between the thickness of the position defining the inner wall of the holding hole in the carrier and the thickness of the position from the inner wall to the radially outer position of 6 mm in the carrier (holding hole of the carrier) Slump) value.

6 is a diagram showing a maximum value of ESFQR for an example.

Claims (12)

A carrier in which the thickness of the position defining the position of the inner wall of the holding hole in the carrier and the thickness of the position of the inner wall of the holding hole in the carrier is from the aforementioned in the carrier The difference in thickness between the inner wall and the position outside 6 mm in the radial direction of the holding hole is 1 μm or less. The carrier according to item 1 of the scope of patent application, wherein the carrier includes a metal part as a main body of the carrier, and is disposed along an inner wall defining an opening portion provided in the metal part for protecting the semiconductor crystal. A circular resin portion having a circular outer peripheral portion, and an opening portion provided in the resin portion constitutes the aforementioned holding hole. The carrier according to item 1 of the scope of patent application, wherein the aforementioned carrier is made of resin. A manufacturing method of a vehicle is the manufacturing method of a vehicle according to any one of claims 1 to 3 of the scope of application for a patent, which comprises processing an original plate made of a predetermined material into a predetermined shape to form a vehicle. A processing step of the intermediate structure of the tool, and a step of adjusting the thickness of the intermediate structure of the carrier to a predetermined thickness and flatness to obtain a thickness adjustment step of the carrier. The thickness adjustment step includes a grinding process step and a grinding process step. The processing amount of the processing step is larger than that of the aforementioned grinding processing step. The method for manufacturing a vehicle according to item 4 of the scope of patent application, wherein the thickness of the intermediate structure of the vehicle before the grinding process step is greater than the thickness of the intermediate structure of the vehicle after the grinding process step 10 μm or more. The method for manufacturing a carrier according to item 4 or 5 of the scope of the patent application, wherein the processing amount of the grinding step is 10 μm or less. An evaluation method of a carrier is an evaluation method of a carrier having a holding hole for holding a semiconductor wafer and applied to a double-side polishing step of the semiconductor wafer, wherein an inner wall of the holding hole is defined in the carrier The thickness of the carrier and the thickness of 6 mm from the inner wall to the radially outer side of the holding hole in the carrier were measured, and it was judged that the quality was good when the difference between the two was 1 μm or less. The method for evaluating a vehicle according to item 7 of the scope of patent application, wherein the vehicle has a metal portion as a vehicle body, and is disposed along an inner wall of the retaining hole defined in the metal portion for use in the vehicle. A ring-shaped resin portion that protects an outer peripheral portion of the semiconductor wafer, and an opening portion provided in the resin portion constitutes the holding hole. The method for evaluating a vehicle according to item 7 of the scope of patent application, wherein the aforementioned vehicle is made of resin. A method for polishing a semiconductor wafer, using the carrier according to any one of claims 1 to 3 in the scope of patent application, and manufacturing the carrier according to any one of claims 4 to 6 in the scope of patent application The carrier manufactured by the method, or a carrier judged to be of good quality according to the carrier evaluation method described in any one of items 7 to 9 of the scope of patent application, performs double-sided polishing of the semiconductor wafer. The polishing method of a semiconductor wafer as described in the patent application item 10, After performing double-side grinding, the thickness of the inner wall of the carrier defining the holding hole and the thickness of the carrier from the inner wall to the radially outer position of 6 mm from the holding wall were measured. When the difference is more than 1 μm, the next double-side polishing is performed with another carrier having a thickness difference of 1 μm or less. The method for polishing a semiconductor wafer according to item 10 or 11 of the scope of patent application, wherein the aforementioned semiconductor wafer is a silicon wafer.