Carrier for double-sided polishing device, double-sided polishing device and double-sided polishing process

Abstract

Carrier (1) for a double-sided polishing device (2) configured for double-sided polishing of a semiconductor silicon wafer, wherein the carrier (1) is arranged between an upper and lower rotary table (3, 4), each having a polishing pad (5) attached thereto, and includes a retaining hole (11) formed therein to hold the semiconductor silicon wafer clamped between the upper and lower rotary tables (3, 4) during polishing, wherein the carrier (1) for a double-sided polishing device (2) is made of a resin, the average contact angle of the front and back surfaces of the carrier (1) coming into contact with the polishing pads (5) with pure water is 45° or more and 60° or less, and the difference in the average contact angles between the front surface and the back surface is 5° or less;wherein the resin-containing support (1) for a double-sided polishing device (2) is a layered resin sheet, and the layered resin sheet comprises a hydrophilic fibrous base material impregnated with a resin; and wherein the hydrophilic fibrous base material of the layered resin sheet has an exposed surface area of ​​50% or more.

Description

TECHNICAL AREA

[0001] The present invention relates to: a support for a double-sided polishing device for holding a semiconductor silicon wafer when the semiconductor silicon wafer is polished on both sides; and a double-sided polishing device and a double-sided polishing method that use this support. STATE OF THE ART

[0002] When both surfaces of a semiconductor silicon wafer (hereinafter also referred to simply as silicon wafer or wafer) are polished simultaneously by a polishing process or the like, the wafer is held by a carrier for a double-sided polishing device. Such a carrier for a double-sided polishing device is designed to have a thickness less than that of the wafer and includes a holding hole for the wafer. The wafer is inserted into and held in the holding hole, and this carrier is positioned at a predetermined location between an upper rotary table and a lower rotary table of the double-sided polishing device.After the polishing pads have been attached to these upper and lower rotary tables, the top and bottom of the wafer are clamped between them, and double-sided polishing is carried out while a polishing compound (slurry) is fed between the upper and lower rotary tables (Patent 1).

[0003] There are various types of carriers for a double-sided polishing device as described above, depending on the substrate material, design and surface finish (e.g. coating and roughness).

[0004] Resin substrates, in particular, offer advantages such as low weight, low cost and simple structure, since their retention holes, unlike those of metal substrates (metallic substrates), do not require an insert to protect a circumferential section of a wafer. COUNTERPOINT LIST PATENT LITERATURE

[0005] Patent specification 1: Unexamined Japanese patent application (Kokai) No. 2015-123553 BRIEF DESCRIPTION OF THE INVENTIONAL PROBLEM

[0006] However, resin-containing substrates are about 40% worse than metallic substrates in terms of the polishing rate for wafers and have a problem with productivity when using double-sided polished wafers.

[0007] The present invention was made with regard to the problem described above. One object of the present invention is to provide: a support for a double-sided polishing device capable of increasing the polishing rate for a semiconductor silicon wafer using a resin-containing support; and a double-sided polishing device and a double-sided polishing method utilizing the support. SOLUTION TO THE PROBLEM

[0008] To solve the problem, the present invention provides a carrier for a double-sided polishing device configured for double-sided polishing of a semiconductor silicon wafer, wherein the carrier is arranged between an upper and lower rotary table, each having a polishing pad attached thereto, and includes a retaining hole formed therein to hold the semiconductor silicon wafer clamped between the upper and lower rotary table during polishing, wherein the carrier for a double-sided polishing device is made of a resin an average contact angle of the front and back surfaces of the carrier coming into contact with the polishing pads and pure water is 45° or more and 60° or less, and a difference in the average contact angle between the front surface and the back surface is 5° or less.

[0009] Such a carrier for a double-sided polishing device is able to significantly increase the polishing rate when double-sided polishing a carrier-held semiconductor silicon wafer compared to the use of a conventional resin-containing carrier for a double-sided polishing device, thus increasing the productivity of the double-sided polished wafer.

[0010] Furthermore, the resin-containing support for a double-sided polishing device can be a layered resin plate, and the layered resin plate has a hydrophilic fibrous base material that is impregnated with a resin.

[0011] Layered resin sheets with resin-impregnated fibrous base materials are frequently used as resin-containing substrates for double-sided polishing devices. The present invention therefore enables manufacturing using conventionally used materials and is easy to produce. Furthermore, the use of such a hydrophilic fibrous base material facilitates the formation of hydrophilic surfaces that exhibit the contact angles with pure water as described above.

[0012] Furthermore, the hydrophilic fibrous base material of the layered resin plate can have an exposed surface area of ​​50% or more.

[0013] Such a configuration allows the front and back surfaces of the carrier for a double-sided polishing device to more reliably meet the contact angle conditions with pure water as described above.

[0014] Furthermore, the present invention provides a double-sided polishing device comprising: an upper and lower rotary table, each with a polishing pad attached to it; a slurry feeding mechanism configured to feed slurry between the upper and lower rotary tables; and a carrier for the double-sided polishing device, wherein the carrier is arranged between the upper and lower rotary tables and includes a retaining hole formed therein to hold a semiconductor silicon wafer which is clamped between the upper and lower rotary tables during polishing, wherein The support for the double-sided polishing device is the inventive support for a double-sided polishing device described above.

[0015] Such a double-sided polishing device is able to significantly increase the polishing rate when double-sided polishing a semiconductor silicon wafer compared to using a conventional resin-coated support for a double-sided polishing device. This allows for increased productivity of the double-sided polished wafer.

[0016] Furthermore, the present invention provides a method for double-sided polishing of a semiconductor silicon wafer, the method comprising: Arranging the inventive support described above for a double-sided polishing device between an upper and lower rotary table, each having a polishing pad attached to it; Holding the semiconductor silicon wafer with a holding hole formed in the carrier for a double-sided polishing device; and Performing double-sided polishing with the addition of a slurry between the upper and lower rotary tables.

[0017] Such a double-sided polishing process makes it possible to significantly increase the polishing rate compared to conventional methods and to increase productivity. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0018] As described above, the inventive support for a double-sided polishing device, the double-sided polishing device comprising the support, and the inventive double-sided polishing method enable a significant increase in the polishing rate compared to the use of a conventional resin-containing support for a double-sided polishing device. This allows for increased productivity. List of characters Fig.Figure 1 is a longitudinal sectional view showing an example of a support for a double-sided polishing device and a double-sided polishing device corresponding to the present invention. Fig. Figure 2 is a diagram of an internal structure, showing an example of the double-sided polishing device in a top view. Fig. Figure 3 is an image taken to show an example of a surface of the resinous support (the inventive support). Fig. Figure 4 is an image taken to show another example of the surface of a resin-containing substrate (conventional substrate). Fig. Figure 5 is a diagram comparing the polishing rates of examples and comparison examples. DESCRIPTION OF THE EXECUTION FORMS

[0019] To solve the aforementioned problem, the present inventors have seriously investigated and discovered that the hydrophilicity on the surface of a resin-containing support contributes to the polishing rate of a semiconductor silicon wafer.

[0020] The inventors have quantified hydrophilicity by measuring the contact angles with pure water. They have found that if the average contact angle between the front and back surfaces of a substrate is 45° or more and 60° or less, and the difference in the average contact angles between the front and back surfaces is 5° or less, the polishing rate for a wafer can be significantly increased. These findings led to the completion of the present invention.

[0021] Embodiments of the present invention are described below with reference to the drawings. However, the present invention is not limited to these.

[0022] Fig. Figure 1 is a longitudinal sectional view of an example of a double-sided polishing device of the present invention, comprising a support for a double-sided polishing device of the present invention. Fig. Figure 2 is a diagram of the internal structure of the double-sided polishing device in a top view.

[0023] As in the Fig. 1 and Fig. 2 shown includes a double-sided polishing device 2 the present invention, which is a carrier 1 for a double-sided polishing device (hereinafter also simply referred to as carrier) of the present invention comprises a lower rotary table 3 and an upper turntable 4 , which are facing each other in a vertical direction, and polishing pads 5 are located on opposite surfaces of the turntables 3 and 4 attached. When the polishing pads 5Foamed polyurethane pads can also be used, for example.

[0024] Furthermore, on an upper section of the upper turntable 4 a sludge feeding mechanism 6 (a nozzle 7 and a through hole 8 in the upper turntable 4 ) provided, which is configured to hold a slurry between the upper rotary table 4 and the lower turntable 3 to be supplied. An aqueous inorganic alkaline solution containing colloidal silica can be used as a slurry.

[0025] Furthermore, on a central section between the upper rotary table 4 and the lower turntable 3 a sun wheel 9 provided; a ring gear is located on a circumferential section in between. 10 provided for. Thus, the one in the Fig. 1 and Fig. 2. The embodiment shown is a type of double-sided 4-way polishing device.

[0026] It is noted that the inventive double-sided polishing device is not limited to such a planetary gear type and can also be an oscillation type.

[0027] A semiconductor silicon wafer W is equipped with a retaining hole 11 in the carrier 1 held and between the upper turntable 4 and the lower turntable 3 trapped.

[0028] This carrier 1 It is made of a resin. An average contact angle with the polishing wheels. 5 front and back surfaces of the carrier coming into contact 1 with pure water is 45° or more and 60° or less, and the difference in the average contact angles between the front surface and the back surface is 5° or less. The inventive holder 1 It meets the contact angle conditions described above. This allows for a higher polishing rate for the wafer. WCompared to the use of a conventional resin-containing substrate, the polishing rate can be significantly increased. For example, the polishing rate can be increased by 10% or more, 25% or more, or even more. Depending on the conventional substrate being compared, the present invention can also double the polishing rate or increase it even further. As a result, the productivity of double-sided polished wafers can be significantly increased.

[0029] Furthermore, the PCA can be used, for example, to measure the contact angle of the carrier. 11The method used is from Kyowa Interface Science Co. Ltd. For example, in this measurement, 2.0 µL drops of pure water are dropped onto each surface at five points, and the contact angles are determined by image analysis. Their average value can be considered the average for each individual surface. Furthermore, when considering the front and back surfaces, an average value and the difference between the average values ​​of the front and back surfaces can be calculated. However, the contact angle measurement method is not limited to this and can be customized in each case. If necessary, the measurement can be performed at more (or fewer) points than five to obtain an average value.

[0030] Additionally, the carrier should 1They must consist of a resin that meets at least the aforementioned predetermined contact angle requirements. Otherwise, the material used is not particularly restricted.

[0031] The carrier is further preferred 1 A layered resin sheet. As an example of the substrate material, a composite material (GFRP) can be used, in which a hydrophilic fibrous base material is impregnated with a resin. Examples of the fibrous base material are glass, liquid crystal polymer, cellulose, and the like. Examples of the resin are epoxy, aramid, phenol, and the like. These materials have been frequently used to date and can easily be adapted for the fabrication of the substrate. 1can be manufactured. However, in the present invention, the hydrophilicity of the front and back surfaces is adapted. These materials facilitate the formation of the carrier with surfaces exhibiting suitable hydrophilicity and are effective in fulfilling the contact angle requirements.

[0032] It is noted that if the hydrophilic fibrous base material of the layered resin plate has an exposed surface area of ​​50% or more, the contact angle conditions mentioned above can be met more reliably. Particularly preferably, the exposed surface area of ​​the fibrous base material is [insert value here] on both the front and back surfaces of the substrate. 150% or more. However, the present invention is naturally not limited to this. The exposed surface area of ​​the fibrous base material can be adjusted as desired, depending on the fibrous base material and the resin used, etc. The contact angle conditions mentioned above should ultimately be met.

[0033] By adjusting the exposed surface area of ​​the hydrophilic fibrous base material to a suitable range, the substrate can be polished under more mechanical conditions than the substrate used for the actual wafer polishing. For example, polishing can be performed using foamed polyurethane pads, while a slurry containing silicon dioxide abrasive grains is applied to expose the fibrous base material.

[0034] Fig.Figure 3 shows an example of a surface where glass fibers were used as the hydrophilic fiber substrate and which exhibited a contact angle of 50.7° with pure water (the inventive support). An image of the support surface is shown. 1 The image was taken under a dark-field microscope. The black color indicates the optical fibers. The optical fibers have an exposed area of ​​67%.

[0035] Fig. Figure 4 shows an example when the contact angle is 66.8° (conventional carrier). In this case, the glass fibers have an exposed area of ​​36%.

[0036] Therefore, the higher the proportion of exposed glass fibers, the smaller the contact angle.

[0037] In this way, the contact angle can vary depending on the exposed area of ​​the hydrophilic fibrous base material. Thus, the carrier can 1, which meets the above contact angle conditions, can be achieved each time by appropriately adjusting the exposed area fraction.

[0038] As in the Fig. 1 and Fig. As shown in section 2, each tooth of the sun gear also engages. 9 and the ring gear 10 into the outer circumferential teeth of the carrier 1 one. If the upper turntable 4 and the lower turntable 3 The carrier rotates when rotated by a drive source not shown. 1 and revolves around the sun wheel 9 around. In this case, the wafer W with the retaining hole 11 in the carrier 1 held, and both surfaces are simultaneously polished with the upper and lower polishing pads. 5 polished. It is noted that a slurry is produced from the nozzle during polishing. 7 through the through-hole 8 is supplied.

[0039] Such a double-sided polishing device comprises the inventive carrier 1 , increases the polishing rate for the wafer W significantly and can therefore increase the productivity of double-sided polished wafers.

[0040] A double-sided polishing method of the present invention comprises: arranging the inventive carrier for a double-sided polishing device described above between upper and lower rotary tables, to which a polishing pad is attached; holding the semiconductor silicon wafer with a holding hole formed in the carrier for a double-sided polishing device; and carrying out the double-sided polishing with the supply of a slurry between the upper and lower rotary tables. This makes it possible to significantly increase the polishing rate and productivity compared to double-sided polishing using a conventional carrier for a double-sided polishing device.

[0041] In particular, for example, as in the Fig. 1 and Fig. 2 shown, the wafer W in the holding hole 11 of the carrier 1 held. Then the carrier 1 , which holds the wafer W, between the upper and lower rotary table 3 and 4 the double-sided polishing device 2 used. While the slurry feeding device 6 When a slurry is applied to the surfaces to be polished, the carrier is then... 1 rotated and set in motion, whereby the upper and lower turntables 3 and 4 rotate. In this way, both surfaces of the wafer W come into sliding contact with the polishing pads. 5 brought about, which enables the double-sided polishing of the wafer W. EXAMPLE

[0042] The present invention is described in detail below, particularly with reference to examples and comparative examples. However, the present invention is not limited thereto. (Examples 1 to 3)

[0043] The inventive supports for a double-sided polishing device were prepared such that each support had different contact angle conditions with the others. Then the in Fig. 1. The double-sided polishing device shown was prepared. A semiconductor silicon wafer, held in the holding hole of one of the carriers for a double-sided polishing device, was positioned between the upper and lower rotary tables and polished on both sides while a slurry was supplied.

[0044] After polishing on both sides, the wafer was cleaned. The polishing rate was calculated based on the difference in thickness before and after polishing.

[0045] The polishing and measuring conditions were as follows. • P-silicon single-crystal wafers with a diameter of 300 mm each were used. • The DSP-20B polishing machine from Fujikoshi Machinery Corp. was used. • Foamed polyurethane pads with a Shore A hardness of 90 were used as polishing pads. • GRP was used as the support material, in which glass fibers were impregnated with epoxy resin. • A KOH-based slurry containing silicon dioxide abrasive grains was used as the slurry, with an average grain size of 35 nm, an abrasive grain concentration of 1.0 wt% and a pH of 10.5. • The processing load was set to 100 gf / cm² 2 set. • The processing time was set so that the wafer thickness was flush with the substrate. • The speed of each drive unit was set as follows: The upper rotary table had -13.4 rpm, the lower rotary table had 35 rpm, the sun gear had 25 rpm and the ring gear had 7 rpm. • The polishing pads were dressed by bringing a dressing plate with electroplated diamond abrasive grains into sliding contact with the upper and lower polishing pads at a predetermined pressure while pure water flowed. • An SC-1 purification was carried out at a ratio of NH4OH:H2O2:H2O=1:1:15.

[0046] The thickness differences of five wafers per batch before and after treatment were measured using a nanometer (manufactured by Kuroda Precision Industries Ltd.). An average of the thickness differences of the five wafers was divided by the polishing time to determine the polishing rate. • A PCA-11 from Kyowa Interface Science Co., Ltd. was used to measure the contact angles of the substrates. In the measurement, 2.0 µL of pure water droplets were dropped onto each surface at five points, and the contact angles were determined by image analysis. Their average value was considered the average value for each individual surface. Furthermore, when considering the front and back surfaces, an average value (Ave) and a difference (Dif) were calculated from the average values ​​of the front and back surfaces. (Comparative examples 1 to 4)

[0047] Conventional carriers for a double-sided polishing device were manufactured, exhibiting contact angle conditions outside the scope of the present invention.

[0048] Apart from the supports for a double-sided polishing device, the same double-sided polishing device as in the examples was prepared, and semiconductor silicon wafers were polished and cleaned on both sides, and the polishing rates were calculated in the same way as in the examples.

[0049] Table 1 shows a summary of the carrier contact angle conditions and polishing rates for Examples 1 to 3 and Comparison Examples 1 to 4. Furthermore, it shows Fig. 5 a diagram of polishing rates. It is noted that the polishing rates are shown in both Table 1 and in Fig. 5 were normalized based on the polishing rate of comparison example 2.

[0050] It should be noted that examples 1 to 3 fulfill both condition A, contact angle with respect to pure water: 45° ≤ Ave ≤ 60°, and condition B: Dif ≤ 5°. Comparison examples 1 to 4 did not fulfill both conditions A and B, or fulfilled only one of them. [Table 1] Comparison example 1 Comparison example 2 Comparison example 3 Comparison example 4 Example l 1 Example l 2 Example 1 3 contact angle Av e 69° 64° 55° 42° 60° 53° 45° Different 9° 3° 7° 2° 3° 5° 2° Condition A not fulfilled not fulfilled fulfilled not fulfilled fulfilled fulfilled fulfilled B not fulfilled fulfilled not fulfilled fulfilled fulfilled fulfilled fulfilled Polishing rate 0,58 1,00 0,67 0,50 1,13 1,17 1,25

[0051] As shown in Table 1 and Fig. As shown in Figure 5, in all examples 1 to 3, which used the carriers for a double-sided polishing device that met both of the contact angle conditions A, B in the present invention, and the double-sided polishing device, the polishing rates were successfully increased compared to comparative examples 1 to 4, which used the carriers for a double-sided polishing device that met at most one of the contact angle conditions A, B in the present invention.

[0052] For example, in contrast to comparison example 2, which served as the reference (polishing rate: 1.00), example 1 was 1.13, representing an increase of 10% or more. Furthermore, example 3 was 1.25, representing an increase of up to 25%. As can also be seen from the comparison between comparison example 4 (0.50) and example 3 (1.25), it was possible to achieve a polishing rate that was more than doubled.

[0053] The comparison between the examples and comparison examples shows that the numerical values ​​of the upper limit and the lower limit of the contact angle conditions in the present invention are critical.

[0054] In example 4 (polishing rate: 0.50), the Ave and Dif values ​​are (42°, 2°), while in example 3 (1.25) they are (45°, 2°). Thus, depending on whether Ave is 45° or more, the polishing rate can be drastically increased.

[0055] It is noted that in comparative example 4, wear was observed when the support used for a double-sided device was being monitored.

[0056] As can be seen from the comparison between example 2 (polishing rate: 1.00) (64°, 3°) and example 1 (1.13) (60°, 3°), the polishing rate was also successfully increased by at least 1.1 times with an average value of 60° or less.

[0057] As can be further seen from the comparison between example 3 (polishing rate: 0.67) (55°, 7°) and example 2 (1.17) (53°, 5°), with a difference of 5° or less the polishing rate was successfully increased by at least 1.7 times.

[0058] It should be noted that the present invention is not limited to the embodiments described above. The embodiments are merely examples, and all examples that exhibit essentially the same properties and demonstrate the same functions and effects as those in the technical concept disclosed in the claims of the present invention are included within the technical scope of the present invention. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] JP 2015123553

[0005]

Claims

[1] Carrier for a double-sided polishing device configured for double-sided polishing of a semiconductor silicon wafer, wherein the carrier is arranged between an upper and lower rotary table, each having a polishing pad attached thereto, and includes a retaining hole formed therein to hold the semiconductor silicon wafer clamped between the upper and lower rotary table during polishing, wherein the carrier for a double-sided polishing device is made of a resin an average contact angle of the front and back surfaces of the carrier coming into contact with the polishing pads and pure water is 45° or more and 60° or less, and a difference in the average contact angle between the front surface and the back surface is 5° or less. [2] Carrier for a double-sided polishing device according to claim 1, wherein The resin-containing carrier for a double-sided polishing device is a layered resin plate, and The layered resin plate has a hydrophilic fibrous base material that is impregnated with a resin. [3] Carrier for a double-sided polishing device according to claim 2, wherein the hydrophilic fibrous base material of the layered resin plate has an exposed surface area of ​​50% or more. [4] Double-sided polishing device comprising: an upper and lower rotary table, each with a polishing pad attached to it; a slurry feeding mechanism configured to feed slurry between the upper and lower rotary tables; and a carrier for the double-sided polishing device, wherein the carrier is arranged between the upper and lower rotary tables and includes a retaining hole formed therein to hold a semiconductor silicon wafer which is clamped between the upper and lower rotary tables during polishing, wherein the support for the double-sided polishing device is the support for the double-sided polishing device according to one of claims 1 to 3. [5] Method for double-sided polishing of a semiconductor silicon wafer, the method comprising: Arranging the carrier for a double-sided polishing device according to one of claims 1 to 3 between an upper and lower rotary table, each having a polishing pad attached thereto; Holding the semiconductor silicon wafer with a holding hole formed in the carrier for a double-sided polishing device; and Performing double-sided polishing with the addition of a slurry between the upper and lower rotary tables.