TW202330174A - Double side polishing apparatus, double side polishing method for semiconductor silicon wafer, double side polished silicon wafer and method for producing same - Google Patents

Abstract

The present invention provides a double side polishing apparatus which is provided with: upper and lower polishing plates, to each of which a polishing cloth is bonded; a slurry supply mechanism which supplies a slurry to the space between the upper and lower polishing plates; and a carrier for double side polishing apparatuses, the carrier being arranged between the upper and lower polishing plates, while being provided with a holding hole for holding a semiconductor silicon wafer that is sandwiched between the upper and lower polishing plates when polished. With respect to this double side polishing apparatus, the carrier for double side polishing apparatuses is a metal carrier which has a contact angle with pure water of 50 DEG or more on the front and back surfaces that are in contact with the polishing cloths; and the polishing cloths have a contact angle with pure water of 100 DEG or more and a compression rate of 5.0% or more. Consequently, the present invention provides: a double side polished silicon wafer which has fewer surface defects, low haze level and high surface quality; and a double side polishing apparatus which is capable of producing such a double side polished silicon wafer.

Description

Double-side grinding device, double-side grinding method of semiconductor silicon wafer, double-side grinding silicon wafer and manufacturing method thereof

The invention relates to a double-side grinding device, a double-side grinding method of a semiconductor silicon wafer, a manufacturing method of a double-side grinding silicon wafer, and a semiconductor silicon wafer.

When simultaneously polishing both sides of a semiconductor silicon wafer (hereinafter, also referred to as "silicon wafer" or "wafer"), etc., the double-sided grinding device uses a carrier (hereinafter , also simply referred to as "carrier") to hold the wafer. The carrier for a double-side polishing device is formed to be thinner than the wafer, and has holding holes for holding the wafer. The wafer is inserted into the holding hole to hold it, and the carrier is arranged at a predetermined position between the upper stage and the lower stage of the double-side polishing device. A polishing cloth is attached to the upper and lower stages to sandwich the upper and lower surfaces of the wafer, and polishing is performed on both sides while supplying abrasive (slurry) between the upper and lower stages (Patent Document 1).

[Prior Art Literature] (patent documents) Patent Document 1: Japanese Patent Laid-Open No. 2015-123553 Patent Document 2: Japanese Patent Laid-Open No. 2015-009315 Patent Document 3: International Publication No. 2018/105306 Patent Document 4: Japanese Patent Laid-Open No. 2006-045757

[Problem to be solved by the invention] In the double-sided grinding generally practiced at present, the surface quality of the wafer is sacrificed in order to ensure the grinding removal rate and the wafer margin, so it is difficult to manufacture a wafer with a high-quality surface. In order to solve such problems, various attempts have been made to adjust polishing members and polishing conditions. So far, reports have been made on various effects of suppressing an increase in polishing removal rate and wear of a member by adjusting the wettability of the polishing member in the double-sided polishing step (Patent Documents 2, 3, etc.). Among them, there is also a report, as described in Patent Document 4, that the contact angle of the surface of the polishing cloth is set to be greater than 60∘ and less than 130∘ to reduce scratches during polishing.

In double-sided polishing of wafers, not only high-precision planarization, which has been a conventional problem, is required, but also high-quality surfaces are required in order to improve the yield of semiconductor devices in recent years. As an evaluation standard of surface quality, surface defects and haze are exemplified. The surface defect is mainly the process-altered layer caused by the defects caused by the abrasive grains in the grinding process; the haze refers to the blurring degree of the wafer surface. To improve these qualities, it is important to select efficient components and conditions, making the selection of the most applicable components and conditions a problem.

The present invention is completed to solve the above-mentioned problems, and the purpose is to provide a double-sided polished silicon wafer having a high-quality surface with few surface defects and a low haze level, and double-sided grinding that can obtain such a double-sided polished silicon wafer. device.

[Technical means to solve the problem] The present invention is completed in order to achieve the above object, and it provides a double-sided grinding device, which has: upper and lower platforms, which are individually attached with polishing cloths; a slurry supply mechanism, which supplies slurry between the upper and lower platforms; and, double-sided A carrier for a grinding device, which is arranged between the aforementioned upper and lower platforms, and is formed with a holding hole to hold the semiconductor silicon wafer sandwiched between the aforementioned upper and lower platforms during grinding; wherein, the carrier for the aforementioned double-sided grinding device A metal carrier having a contact angle of 50∘ or more with respect to the pure water on the surface and the back surface in contact with the abrasive cloth; above.

According to this double-side polishing apparatus, it is possible to obtain a double-side polished silicon wafer having a high-quality surface with few surface defects and a low haze level.

In this case, the abrasive cloth may be a foamed urethane-based or non-woven cloth-based abrasive cloth having a Shore hardness A of 70 or more.

This enables stable double-sided ground silicon wafers with high-quality surfaces to be obtained.

At this time, it can be set as a double-sided grinding method of a semiconductor silicon wafer, and the carrier for the double-sided grinding device is arranged between the upper and lower platforms individually attached with grinding cloth; the aforementioned semiconductor silicon wafer is held In the holding hole formed in the carrier for the double-sided polishing device, double-sided polishing is performed while supplying the slurry between the upper and lower platforms; wherein the double-sided polishing method uses the above-mentioned double-sided polishing device.

According to this double-side grinding method of a semiconductor silicon wafer, a double-side ground silicon wafer having a high-quality surface with few surface defects and a low haze level can be obtained.

In this case, it can be set as a method of manufacturing a double-side ground silicon wafer, and a double-side ground silicon wafer is produced by the above-mentioned double-side grinding method of a semiconductor silicon wafer.

Thereby, a double-sided polished silicon wafer having a high-quality surface with few surface defects and a low level of haze can be manufactured.

The present invention also provides a double-sided ground silicon wafer, converted to a wafer with a diameter of 300 mm, with less than 10 surface defects of 90 nm or more detected by a light scattering particle counter and a haze of less than 1.0 ppm.

The double-side ground silicon wafer has a high-quality surface with few surface defects and a low level of haze, and is beneficial to improving the yield rate of semiconductor devices.

[Effect of the invention] As above, according to the double-side polishing apparatus of the present invention, it is possible to obtain a double-side polished silicon wafer having a high-quality surface with few surface defects and a low haze level. According to the double-side grinding method of the semiconductor silicon wafer of the present invention, a double-side ground silicon wafer having a high-quality surface with few surface defects and a low haze level can be obtained. In addition, the double-sided ground silicon wafer of the present invention has a high-quality surface with few surface defects and a low level of haze, and is beneficial to improving the yield rate of semiconductor devices and the like.

Hereinafter, the present invention will be described in detail, but the present invention is not limited to these embodiments.

As described above, a double-sided polished silicon wafer having a high-quality surface with few surface defects and a low haze level, and a double-sided polishing apparatus capable of manufacturing such a double-sided polished silicon wafer are desired.

The present inventor repeatedly carried out creative examinations on the above-mentioned problems, and found a double-sided grinding device with: upper and lower platforms, which are individually attached with grinding cloths; a slurry supply mechanism, which supplies slurry between the upper and lower platforms; and , a carrier for a double-sided grinding device, which is arranged between the aforementioned upper and lower platforms, and is formed with a holding hole to hold the semiconductor silicon wafer sandwiched between the aforementioned upper and lower platforms when grinding; wherein the aforementioned double-sided grinding The device carrier is a metal carrier having a contact angle of 50∘ or more to pure water on the surface and the back surface in contact with the abrasive cloth; the aforementioned abrasive cloth has a contact angle to pure water of 100∘ or more and the compression 5.0% or more; with this double-sided polishing device, a double-sided polished silicon wafer with a high-quality surface having fewer surface defects and a low haze level can be obtained, thereby completing the present invention.

The inventors of the present invention have found a double-sided ground silicon wafer. Converted to a wafer with a diameter of 300mm, the number of surface defects above 90nm detected by a light scattering particle counter is less than 10 and the haze is less than 1.0ppm; This is useful for improving the yield rate of the semiconductor device, etc., thereby completing the present invention.

Hereinafter, description will be made with reference to the drawings.

[Double-sided grinding device] First, the double-sided polishing device of the present invention will be described. Fig. 1 is a vertical cross-sectional view of an example of a double-sided polishing device according to the present invention; Fig. 2 is an internal structural view of the double-sided polishing device in plan view. As shown in Fig. 1 and Fig. 2, regarding the double-sided grinding device 2 of the present invention, it is equipped with a lower platform 3 and an upper platform 4 that are arranged to face up and down, and on the opposite side of each platform 3, 4, A polishing cloth 5 is attached individually. Also, a slurry supply mechanism 6 (nozzle 7 and through hole 8 of the upper platform 4 ) is provided on the upper part of the upper platform 4 to supply the slurry between the upper platform 4 and the lower platform 3 . As the slurry, for example, an inorganic alkaline aqueous solution containing colloidal silica can be used.

In the aspect shown in Fig. 1 and Fig. 2, it is a double-sided grinding device of a 4way type, which is provided with a sun gear 9 at the center between the upper platform 4 and the lower platform 3; internal gear 10. In addition, the double-sided polishing apparatus of the present invention is not limited to such a planetary gear type polishing apparatus, and may be a swing type polishing apparatus.

The semiconductor silicon wafer W is held in the holding hole 11 of the carrier 1 for a double-side polishing apparatus, and is sandwiched between the upper stage 4 and the lower stage 3 . This double-sided polishing device carrier 1 is made of metal, and has a contact angle (hereinafter, simply referred to as "contact angle") of pure water on the surface and the back surface in contact with the polishing cloth 5 of 50∘ or more. When the contact angle is less than 50∘, the number of surface defects increases. In addition, the upper limit of the contact angle is not particularly limited, and the larger the contact angle, that is, the higher the water repellency, the better, but it can be set to 80∘ or less, for example. In addition, the carrier may be made of metal, and examples of metal include SUS, titanium, and the like. By using a metal carrier, the grinding removal rate can be improved. In addition, the contact angle between the surface and the back of the carrier can be adjusted according to the change of the metal base material. The preferred contact angle is 60±5∘.

The polishing cloth 5 used has a contact angle to pure water of 100∘ or more and a compressibility of 5.0% or more. When the contact angle is less than 100∘, sufficient reduction of the haze level cannot be expected. Also, when the compressibility is less than 5.0%, the number of surface defects increases.

The upper limit of the contact angle of the polishing cloth is not particularly limited, and the larger the contact angle, that is, the higher the water repellency, the better. However, for example, it can be set to 150∘ or less. The contact angle of the polishing cloth can be adjusted by adding materials etc. when making the polishing cloth. The better contact angle is 120±10∘.

Also, the upper limit of the compressibility of the polishing cloth is not particularly limited, and the higher the compressibility, the better, but it can be set to 15% or less, for example. The compressibility of the abrasive cloth can be adjusted by additives etc. in the preparation of the abrasive cloth. A more preferable compression rate is 5.0% or more and 10.0% or less. In addition, the compressibility of the abrasive cloth is regulated by JIS L1096.

In addition, as the polishing cloth 5 , for example, a foamed urethane-based or non-woven cloth-based polishing cloth can be used, and a polishing cloth having a Shore hardness A of 70 or more is preferable. Because it can obtain stable double-sided ground silicon wafers with high-quality surfaces. The upper limit of the Shore hardness A is not particularly limited, but for example, a polishing cloth of 90 or less can be used.

In addition, for the measurement of the contact angle of the carrier and the polishing cloth, for example, PCA-11 of Kyowa Interface Science Co., Ltd. can be used. For the measurement, for example, a 2.0 μL drop of pure water can be dropped on the evaluation surface, and the contact angle can be obtained from the screen analysis. However, the contact angle measurement method is not limited thereto and can be appropriately determined.

Furthermore, as shown in FIGS. 1 and 2, the outer peripheral teeth of the carrier 1 are engaged with the teeth of the sun gear 9 and the internal gear 10, and the upper platform 4 is driven by a driving source not shown. With the rotation of the lower platform 3, the carrier 1 revolves around the sun gear 9 while rotating on its own. At this time, the semiconductor silicon wafer W is held by the holding hole 11 of the carrier 1 , and both sides are simultaneously polished by the upper and lower polishing cloths 5 . In addition, when grinding, the slurry is supplied from the nozzle 7 through the through hole 8 .

This double-sided lapping device can obtain double-sided lapped silicon wafers with high-quality surfaces with few surface defects and low haze levels

[Double-side grinding method and double-side grinding silicon wafer manufacturing method] The double-side polishing method of the semiconductor silicon wafer of the present invention is a method performed using the above-mentioned double-side polishing apparatus of the present invention. That is, using the double-side grinding device of the present invention, a carrier for the double-side grinding device is arranged between the upper and lower platforms on which the grinding cloth is individually attached, and the semiconductor silicon wafer is held on the surface formed on the double-side grinding device. Hold the hole of the carrier for the device, and perform double-sided polishing while supplying the slurry between the upper and lower stages.

Specifically, for example, as shown in FIG. 1 and FIG. 2 , the carrier 1 capable of holding the semiconductor silicon wafer W is inserted between the upper and lower platforms 3 and 4 of the double-side grinding device 2 . Next, the semiconductor silicon wafer W is held in the holding hole 11 of the carrier 1 . Furthermore, while the slurry is supplied to the polishing surface by the slurry supply mechanism 6 , the upper and lower stages 3 and 4 are rotated, and the carrier 1 is rotated and revolved. In this way, both sides of the semiconductor silicon wafer W are brought into sliding contact with the polishing cloth 5 , whereby both sides of the semiconductor silicon wafer W can be polished.

If the double-sided polishing method of semiconductor silicon wafers according to the present invention is used, it is possible to manufacture double-sided polished silicon wafers having a high-quality surface with few surface defects and a low haze level.

[Double-sided grinding silicon wafer] As described above, the double-sided polishing method of semiconductor silicon wafers implemented using the double-sided polishing apparatus of the present invention can obtain double-sided polished silicon wafers with high-quality surfaces. Specifically, it is a double-sided polished silicon wafer with a diameter of 300 mm converted to a wafer with a surface defect of 90 nm or more detected by a light-scattering particle counter with less than 10 and a haze of 1.0 ppm or less. The double-side ground silicon wafer has a high-quality surface with few surface defects and a low haze level, and is beneficial to improving the yield rate of semiconductor devices. In addition, the diameter, conduction form, and surface direction of the main surface of the silicon wafer are not particularly limited.

[Example] Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these Examples.

(Common Experimental Conditions) As a double-side polishing device, DSP-20B manufactured by Fujikoshi Machinery Co., Ltd., which is a 4way type double-side polishing device, was used. A foamed urethane pad with a Shore A hardness of 78 is used for the abrasive cloth; the slurry is a slurry containing silicon oxide abrasive grains, an average particle size of 35nm, an abrasive grain concentration of 1.0wt%, a pH of 10.5, and a KOH-based slurry. The object of the double-side grinding process was a P-type silicon wafer with a main surface of (100) and a diameter of 300 mm, and a total of 5 wafers were subjected to double-side grinding processing. The processed wafer was subjected to SC-1 cleaning under the condition of NH ₄ OH:H ₂ O ₂ :H ₂ O=1:1:15.

The contact angle of the carrier and the abrasive cloth was measured with a portable contact angle measuring instrument manufactured by Kyowa Interface Science Co., Ltd. The surface quality of double-sided polished silicon wafers with surface defects and haze was measured with the laser scattering particle counter SP5 manufactured by KLA. For the measurement conditions, refer to the haze measured in the DW-2 channel.

(comparative example 1,2) First, only the compressibility of the polishing cloth was changed as follows, and the conditions other than the compressibility of the polishing cloth were the same. Comparative Example 1: The compression ratio of the abrasive cloth is set to 2.0% Comparative Example 2: The compression ratio of the abrasive cloth is set to 9.0% Unify components and polishing conditions such as carriers and slurries that affect the surface quality other than the compressibility of the polishing cloth to investigate the influence of the difference in the compressibility of the polishing cloth on the surface quality of double-sided polished silicon wafers . In addition, the carrier used and the contact angle conditions of the polishing angle were 30∘ for the carrier and 50∘ for the polishing cloth.

Fig. 3 shows the results of comparing the number of surface defects. Figure 4 shows the results of comparing haze levels. As shown in Figures 3 and 4, it can be seen that the surface defects and haze of the wafer polished with the polishing cloth of Comparative Example 2 with a compression ratio of 9.0% are low, and compared with the compression ratio of Comparative Example 1 Low abrasive cloths are more suitable.

(Example 1) Prepare a carrier made of SUS metal base material with a contact angle of 50∘ (water repellency) on the front and back as a carrier, and prepare a polishing cloth with a contact angle of 100∘ (water repellency) and a compressibility of 5.0% or more As a polishing cloth, perform double-sided polishing of silicon wafers and investigate surface quality. As a result, the number of surface defects was 16 at maximum and 9.8 on average. Moreover, the haze level was 0.88 ppm at the maximum and 0.71 ppm on average. It was a good result that both surface defects and haze were low.

(Comparative Examples 3-5, Example 2) Based on the results of Comparative Examples 1 and 2 above, in Example 2 and Comparative Examples 3 to 5, a polishing cloth having a compressibility of 9.0% was used. For the contact angle between the carrier and the abrasive cloth, prepare a carrier with a contact angle of less than 50∘ (hydrophilic) and a carrier with a contact angle of 50∘ or more (water repellent); prepare a abrasive cloth with a contact angle of less than 100∘ (hydrophilic). ) abrasive cloth and abrasive cloth above 100∘ (water repellent). Fig. 5 shows the measurement results of the contact angles of the prepared two types of carriers, and Fig. 6 shows the measurement results of the contact angles of the prepared two types of polishing cloths.

The prepared carrier and polishing cloth were combined as follows to perform double-sided polishing of the silicon wafer and investigate the surface quality. Comparative Example 3: The contact angle of the carrier is less than 50∘ (hydrophilic) + the contact angle of the abrasive cloth is less than 100∘ (hydrophilic) Comparative Example 4: The contact angle of the carrier is less than 50∘ (hydrophilic) + the contact angle of the abrasive cloth is more than 100∘ (water repellent) Comparative Example 5: The contact angle of the carrier is 50∘ or more (water repellent) + the contact angle of the abrasive cloth is less than 100∘ (hydrophilic) Example 2: The contact angle of the carrier is 50∘ or more (water repelling) + the contact angle of the abrasive cloth is 100∘ or more (water repelling)

Fig. 7 shows the results of comparing the number of surface defects. Fig. 8 shows the results of comparing haze levels. As shown in FIG. 7 and FIG. 8, it can be seen that the surface quality of the wafer of Example 2 is the highest. Regarding the number of surface defects, even the maximum value of the wafer of Example 2 was less than 10 (the average value was 4.8), and the variation was small. Also, regarding the haze level, the wafer of Example 2 was at a low level even at a maximum value of less than 1.0 ppm (average value: 0.64 ppm).

In the grinding conditions of embodiments 1 and 2, any one of the carrier and the polishing cloth is set to a high water-repellent condition, so the improvement of the surface quality of the double-sided grinding wafer can be determined as a member of the water-repellent system (the surface of the carrier) The contact angle is 50∘ or more, and the contact angle of the abrasive cloth is 100∘ or more), and the abrasive cloth with high compressibility is the most suitable.

In addition, this invention is not limited to the said embodiment. The above-mentioned embodiments are examples, and any embodiment that has substantially the same configuration and exerts the same effect as the technical idea described in the claims of the present invention is included in the technical scope of the present invention.

1: Carrier (carrier for double-sided grinding device) 2: Double-sided grinding device 3: Get off the platform 4: on the platform 5: Grinding cloth 6: Slurry supply mechanism 7: Nozzle 8: Through hole 9: sun gear 10: Internal gear 11: Hold hole W: silicon wafer (semiconductor silicon wafer)

Fig. 1 is a longitudinal sectional view showing an example of a double-side polishing device according to the present invention. Fig. 2 is an internal structural diagram showing an example of a double-side polishing device in plan view. Fig. 3 shows the results of comparing the number of surface defects with respect to Comparative Examples 1 and 2. Fig. 4 shows the results of comparison of haze levels with respect to Comparative Examples 1 and 2. Fig. 5 shows the measurement results of the contact angles of the carriers used in Example 2 and Comparative Examples 3-5. Fig. 6 shows the measurement results of the contact angles of the polishing cloths used in Example 2 and Comparative Examples 3-5. Fig. 7 shows the results of comparing the number of surface defects with respect to Examples 1 and 2 and Comparative Examples 3-5. Fig. 8 shows the results of comparison of haze levels with respect to Examples 1 and 2 and Comparative Examples 3-5.

Domestic deposit information (please note in order of depositor, date, and number) none

Overseas storage information (please note in order of storage country, organization, date, and number) none

1: Carrier (carrier for double-sided grinding device)

2: Double-sided grinding device

3: Get off the platform

4: on the platform

5: Grinding cloth

6: Slurry supply mechanism

7: Nozzle

8: Through hole

9: sun gear

10: Internal gear

W: silicon wafer (semiconductor silicon wafer)

Claims (5)

A double-sided grinding device, comprising: Upper and lower platforms, which are individually attached with abrasive cloths; a slurry supply mechanism that supplies slurry between the upper and lower platforms; and, A carrier for a double-sided grinding device, which is arranged between the upper and lower platforms, and is formed with a holding hole to hold the semiconductor silicon wafer sandwiched between the upper and lower platforms during grinding; The double-sided polishing device is characterized in that the carrier for the double-sided polishing device is a metal carrier with a contact angle of 50∘ or more for pure water on the surface and the back surface in contact with the polishing cloth; The aforementioned polishing cloth has a contact angle with respect to pure water of 100∘ or more and a compressibility of 5.0% or more. The double-sided polishing device according to claim 1, wherein the polishing cloth is a foamed urethane-based or non-woven cloth-based polishing cloth having a Shore hardness A of 70 or higher. A method for double-sided grinding of semiconductor silicon wafers. The carrier for the double-sided grinding device is arranged between the upper and lower platforms individually attached with grinding cloth; the aforementioned semiconductor silicon wafer is held on the double-sided surface The holding hole of the carrier for the grinding device, and performs double-sided grinding while supplying the slurry between the aforementioned upper and lower platforms; The double-sided grinding method is characterized by comprising the double-sided grinding device described in claim 1 or 2. A method for manufacturing a double-side ground silicon wafer, characterized in that the double-side ground silicon wafer is produced by the method for manufacturing a double-side ground silicon wafer described in Claim 3. A double-sided ground silicon wafer is characterized in that, converted to a wafer with a diameter of 300 mm, the number of surface defects of 90 nm or more detected by a light scattering particle counter is less than 10 and the haze is less than 1.0 ppm.