JP2011240460A - Carrier for double-side polishing apparatus and double-side polishing apparatus using the same, and double-side polishing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier for a double-side polishing apparatus, a double-side polishing apparatus and a double-side polishing method which suppress deterioration in the shape of a chamfered portion of a wafer, and the occurrence of scratches in the plane of the wafer and the chamfered portion while preventing the breakage of a peripheral edge of the wafer.SOLUTION: The carrier for the double-side polishing apparatus for polishing double sides of a wafer having a chamfered portion at its peripheral edge includes at least a carrier base body which is disposed between upper and lower surface plates having polishing cloths attached thereto, respectively, and has a holding hole for holding the wafer sandwiched between the upper and lower surface plates during the polishing of the wafer, and a ring-shaped resin ring which is disposed along the inner circumference of the holding hole in the carrier base body, and brought into contact with the chamfered portion of the wafer to be held to protect the chamfered portion. The tensile modulus of the resin ring based on the tensile test in compliance with ASTM D638 is ≥12 GPa and ≤20 GPa, and the resin ring is formed of the resin not containing any inorganic reinforcing material.

Description

  The present invention relates to a double-side polishing apparatus carrier for holding a wafer when polishing the wafer in a double-side polishing apparatus, and a double-side polishing method using the apparatus including the carrier.

  When simultaneously polishing both surfaces of the wafer by polishing or the like, the wafer is held by a carrier for a double-side polishing apparatus. The carrier for a double-side polishing apparatus is formed with a thickness thinner than that of the wafer, and includes a holding hole for holding the wafer at a predetermined position between the upper and lower surface plates of the double-side polishing apparatus. The wafer is inserted and held in this holding hole, and the upper and lower surfaces of the wafer are sandwiched by polishing tools such as polishing cloth provided on the opposing surfaces of the upper and lower surface plates, and both surfaces are supplied while supplying the polishing agent to the polishing surface. At the same time, polishing is performed.

Here, the carrier for the double-side polishing apparatus used for double-side polishing of such a wafer is mainly made of metal.
For this reason, in order to protect the peripheral part of a wafer from the damage by the metal carrier for double-side polish apparatuses, the resin ring is attached along the inner peripheral part of a holding hole.
In this way, it is possible to prevent the peripheral edge of the wafer from being damaged by attaching and polishing the resin ring between the holding hole of the carrier and the wafer.

Normally, the periphery of the wafer is chamfered, and when performing double-side polishing of a wafer having a chamfered portion on the periphery as described above, the peripheral portion of the wafer is worn by contact between the wafer and the resin ring, and the chamfering is performed. There was a problem that the shape deteriorated.
In order to suppress the deterioration of the chamfered shape of the wafer against such problems, the shape of the inner end surface with which the wafer is held in the holding hole of the carrier made of epoxy resin was formed in the same shape as the chamfered portion of the wafer. A carrier for double-side polishing (see Patent Document 1) and a region including the peripheral portion of the work holding hole are configured by concentrically orienting glass fibers impregnated with resin, and curved on the inner peripheral surface of the work holding hole. A polishing machine carrier (see Patent Document 2) in which a recess is formed is disclosed.

JP-A-8-197416 JP 2000-301451 A

However, even if double-side polishing of a wafer having a chamfered portion is performed using such a conventional carrier, although the wear of the peripheral portion can be suppressed to some extent, the chamfered shape is still deformed and deteriorated.
Furthermore, depending on the carrier, there is a problem that scratches occur in the wafer surface or in the chamfered portion.

  Therefore, the inventors conducted experiments for investigating the deterioration of the chamfered shape of the wafer and the cause of occurrence of scratches in the wafer surface or in the chamfered portion, and repeated investigations. As a result, it was found that the chamfered shape of the wafer deteriorates when a resin ring having a low tensile elastic modulus is used. Further, when the material of the resin ring includes an inorganic reinforcing material such as glass fiber or inorganic filler, the reinforcing material is finely crushed during the polishing of the wafer, and scratches are generated in the wafer surface or in the chamfered portion. It was revealed.

  The present invention has been made in view of the above-described problems, and is capable of suppressing the deterioration of the chamfered shape of the wafer and the generation of scratches in the wafer surface or in the chamfered portion while preventing damage to the peripheral portion of the wafer. It is an object of the present invention to provide a carrier for a polishing apparatus, a double-side polishing apparatus and a double-side polishing method using the same.

  In order to achieve the above object, according to the present invention, there is provided a carrier for a double-side polishing apparatus in a double-side polishing apparatus for polishing both surfaces of a wafer having a chamfered portion at the periphery, at least an upper and lower surface plate to which a polishing cloth is stuck And a carrier base having a holding hole for holding the wafer sandwiched between the upper and lower surface plates during polishing, and an inner periphery of the holding hole of the carrier base A ring-shaped resin ring that is in contact with the chamfered portion of the held wafer and protects the chamfered portion, and the resin ring has a tensile modulus of elasticity of 12 GPa or more based on a tensile test based on ASTM D638, There is provided a carrier for a double-side polishing apparatus characterized by being made of a resin that is 20 GPa or less and does not contain an inorganic reinforcing material.

  Thus, if the resin ring has a tensile elastic modulus of 12 GPa or more and 20 GPa or less based on a tensile test based on ASTM D638 and is made of a resin not containing an inorganic reinforcing material, It becomes a carrier for a double-side polishing apparatus capable of suppressing the deterioration of the chamfered shape of the wafer and the generation of scratches in the wafer surface or in the chamfered portion while preventing breakage. As a result, the product yield can be improved.

  At this time, the tensile modulus based on the tensile test based on the ASTM D638 is 12 GPa or more and 20 GPa or less, and specifically, as a resin not containing an inorganic reinforcing material, specifically, wood powder-filled phenol resin, chipped roving filling failure Any of a saturated polyester resin, a polyamideimide resin, an allyl resin, and a wholly aromatic liquid crystal polyester resin can be used.

Moreover, according to this invention, the double-side polish apparatus provided with the carrier for double-side polish apparatuses which concerns on the said this invention at least is provided.
Thus, if double-side polishing of the wafer is performed using the double-side polishing apparatus provided with the carrier for double-side polishing apparatus according to the present invention, the chamfered shape of the wafer is deteriorated while preventing damage to the peripheral edge of the wafer to be polished. It is possible to perform double-side polishing of the wafer while suppressing the generation of scratches in the wafer surface or in the chamfered portion.

  Further, according to the present invention, there is provided a method for polishing a wafer on both sides, wherein the carrier for a double-side polishing apparatus of the present invention is disposed between upper and lower surface plates to which a polishing cloth is attached, and the holding holes of the carrier are provided. A resin ring made of a resin having a tensile modulus of elasticity of 12 GPa or more and 20 GPa or less according to ASTM D638 tensile test disposed on the inner periphery is held in contact with the chamfered portion of the wafer, and the wafer is placed between the upper and lower surface plates. A double-side polishing method for a wafer is provided, characterized in that the double-side polishing is performed with the wafer sandwiched therebetween.

  As described above, the resin ring made of a resin having a tensile elastic modulus of 12 GPa or more and 20 GPa or less by the ASTM D638 tensile test arranged on the inner periphery of the carrier holding hole is held in contact with the chamfered portion of the wafer. If the wafer is sandwiched between the upper and lower surface plates and polished on both sides, damage to the peripheral portion of the wafer can be prevented, and deterioration of the chamfered shape of the wafer and occurrence of scratches in the wafer surface and in the chamfered portion can be suppressed. . Thereby, the product yield can be improved.

  The carrier for a double-side polishing apparatus of the present invention has a resin ring made of a resin having a tensile elastic modulus of 12 GPa or more and 20 GPa or less based on a tensile test based on ASTM D638, and does not contain an inorganic reinforcing material. While preventing the peripheral edge from being damaged, it is possible to suppress the deterioration of the chamfered shape of the wafer and the generation of scratches in the wafer surface or in the chamfered portion.

It is the schematic sectional drawing which showed an example of the double-side polish apparatus of this invention. It is an internal structure figure of the double-side polish apparatus of this invention by planar view. It is the schematic which showed an example of the carrier for double-side polish apparatuses of this invention. It is explanatory drawing showing a mode that the peripheral part (chamfering part) of the wafer contacted the internal peripheral surface of the resin ring of the carrier for double-side polish apparatuses of this invention. It is a figure which shows the shape of the peripheral part of the wafer after grinding | polishing in Example 1. FIG. It is a figure which shows the shape of the peripheral part of the wafer after grinding | polishing in the comparative example 1. FIG. It is a figure which shows the shape of the peripheral part of the wafer after grinding | polishing in the comparative example 2. FIG.

Hereinafter, although an embodiment is described about the present invention, the present invention is not limited to this.
Conventionally, when performing double-side polishing of a wafer having a chamfered portion at the periphery, there has been a problem that the peripheral portion of the wafer is worn by contact between the carrier and the wafer, and the chamfered shape deteriorates. For this problem, a double-side polishing machine carrier is known in which a curved concave portion is formed on the inner peripheral surface of a holding hole of a glass fiber carrier impregnated with an epoxy resin or a resin in order to suppress deterioration of the chamfered shape of the wafer. However, even when such a carrier is used, the chamfered shape may still deteriorate. Further, depending on the material of the carrier, there is a problem that scratches occur in the wafer surface or in the chamfered portion.

  Therefore, the present inventors have made extensive studies to solve such problems. As a result, it was found that the chamfered shape of the wafer deteriorates when a resin ring having a low tensile elastic modulus is used. In addition, the tensile modulus of elasticity of the resin ring can be increased by including, for example, glass fiber or inorganic filler as a reinforcing material. In this case, the reinforcing material is finely crushed during the polishing of the wafer, which is the wafer. It became clear that it was a cause of scratches in the in-plane or chamfer.

  Then, the inventors further experimented, and if the resin ring is made of a resin having a tensile modulus of elasticity of 12 GPa or more and 20 GPa or less based on a tensile test based on ASTM D638 and not containing an inorganic reinforcing material. The inventors have found that the change in shape due to wear of the chamfered portion of the wafer can be suppressed while preventing the peripheral edge of the wafer from being damaged, and the occurrence of scratches in the wafer surface and the chamfered portion can also be suppressed, thereby completing the present invention.

  Here, FIG. 1 is a schematic sectional view of a double-side polishing apparatus provided with the carrier for double-side polishing apparatus of the present invention, and FIG. 2 is an internal structural view of the double-side polishing apparatus in plan view.

  As shown in FIGS. 1 and 2, a double-side polishing apparatus 20 provided with the carrier 1 for a double-side polishing apparatus of the present invention includes an upper surface plate 6 and a lower surface plate 7 provided opposite to each other in the vertical direction, A polishing cloth 5 is affixed to the opposing surface side of each of the surface plates 6 and 7. A sun gear 9 is provided at the center between the upper surface plate 6 and the lower surface plate 7, and an internal gear 10 is provided at the peripheral portion. The wafer W is held in the holding hole 4 of the carrier 1 for double-side polishing apparatus, and is sandwiched between the upper surface plate 6 and the lower surface plate 7.

  The teeth of the sun gear 9 and the internal gear 10 are engaged with the outer peripheral teeth of the double-side polishing machine carrier 1, and the upper surface plate 6 and the lower surface plate 7 are rotated by a drive source (not shown). Accordingly, the carrier 1 for double-side polishing apparatus revolves around the sun gear 9 while rotating. At this time, the wafer W is held in the holding holes 4 of the carrier 1 for a double-side polishing apparatus, and both sides are simultaneously polished by the upper and lower polishing cloths 5. In polishing, a polishing liquid is supplied from a nozzle (not shown).

As shown in FIG. 3, the double-side polishing apparatus carrier 1 has a metal carrier base 3 in which a holding hole 4 for holding a wafer W is formed. A resin ring 2 is arranged along the inner peripheral surface of the holding hole 4 of the carrier base 3.
The resin ring 2 in the carrier for a double-side polishing apparatus according to the present invention has a tensile elastic modulus of 12 GPa or more and 20 GPa or less based on a tensile test based on ASTM D638. It is made of a resin that does not contain.

The wafer W is inserted and held in the holding hole 4 of the carrier 1 for double-side polishing apparatus in which such a resin ring 2 is disposed on the inner peripheral surface. The resin ring 2 can prevent the wafer W from coming into contact with the metallic carrier base 3 during polishing to cause damage such as cracks in the peripheral edge of the wafer W.
Here, FIG. 4 shows a state in which the wafer W is inserted into the holding hole 4 of the carrier 1 for double-side polishing apparatus, and the peripheral portion of the wafer W is in contact with the inner peripheral surface of the resin ring 2.
As shown in FIG. 4, the peripheral portion of the wafer W to be polished is chamfered and has a chamfered portion 8. The periphery of the wafer W having the chamfered portion 8 is brought into contact with the inner periphery of the resin ring 2 to hold the wafer W.

Here, the inner peripheral surface of the resin ring 2 shown in FIG. 4 is formed flat. When the polishing of the wafer W is repeatedly performed, the inner peripheral surface gradually becomes a concave shape along the shape of the chamfered portion 8 of the wafer W. Or you may form in the concave shape along the shape of the chamfered part 8 of the wafer W from the beginning. In the present invention, the shape of the inner peripheral surface of the resin ring 2 is not particularly limited.
When a conventional resin ring made of a soft resin having a tensile modulus of elasticity of less than 12 GPa is used, the resin ring is formed in a concave shape along the shape of the chamfered portion 8 of the wafer W as described above. Even if it has, the peripheral part of the wafer W is deformed into a shape recessed toward the inner side of the wafer W due to wear, particularly in the vicinity of the center in the thickness direction, and the chamfered shape deteriorates.

In the carrier for a double-side polishing apparatus of the present invention, since the resin ring 2 uses a resin having a tensile modulus of elasticity of 12 GPa or more, deformation due to wear of the chamfered portion 8 of the wafer W can be suppressed. Further, since the tensile elastic modulus is 20 GPa or less, damage such as cracks does not occur in the peripheral portion of the wafer W due to the hardness of the resin ring 2.
Furthermore, since the resin ring 2 of the present invention does not include an inorganic reinforcing material, it is possible to suppress the generation of scratches in the wafer surface or the chamfered portion 8 due to the inorganic reinforcing material being finely crushed.

At this time, as a resin having a tensile modulus of elasticity of 12 GPa or more and 20 GPa or less based on a tensile test based on the ASTM D638 and does not include an inorganic reinforcing material, wood powder-filled phenol resin, chipped roving-filled unsaturated polyester resin Thermosetting resins such as polyamideimide resin and allyl resin, and thermoplastic resins such as wholly aromatic liquid crystal polyester resin can be used.
In general, the wholly aromatic liquid crystalline polyester resin has the highest tensile elastic modulus (19.69 GPa) among the resins not including the inorganic reinforcing material, and therefore the deformation of the chamfered shape of the wafer W of the present invention. In order to simultaneously exhibit the effect of suppressing the generation of scratches in the wafer surface or in the chamfered portion 8, the tensile elastic modulus needs to be 20 GPa or less.

  Such a resin ring 2 can be attached to the carrier 1 for a double-side polishing apparatus by forming the resin into a sheet shape by extrusion molding, then processing it into a ring shape, and fitting the resin ring 2 into the carrier base material 3. Alternatively, resin pellets may be used as raw materials and directly injection-molded and mounted on the carrier base material 3.

  2 and 3, each double-side polishing apparatus carrier 1 holds one wafer W, but it can also be a double-side polishing apparatus carrier having a plurality of holding holes 4. A plurality of wafers W may be held in each double-side polishing machine carrier.

Next, the double-side polishing method for a wafer of the present invention will be described below.
The wafer double-side polishing method of the present invention has a resin ring 2 made of a resin having a tensile modulus of elasticity of 12 GPa or more and 20 GPa or less based on a tensile test based on ASTM D638 and not containing an inorganic reinforcing material. A double-side polishing apparatus carrier 1 as shown in FIG. 1 and a double-side polishing apparatus 20 as shown in FIG. 1 equipped with the double-side polishing apparatus carrier 1 are used. A carrier 1 for a double-side polishing apparatus is disposed between the boards 6 and 7.

Next, the wafer W is inserted into the holding hole 4 of the carrier 1 for double-side polishing apparatus, and the peripheral edge having the chamfered portion 8 of the resin ring 2 and the wafer W disposed on the inner periphery of the holding hole 4 of the carrier 1 for double-side polishing apparatus Hold the part in contact.
Then, the upper and lower polishing surfaces of the wafer W are sandwiched between the polishing cloths 5 affixed to the upper and lower surface plates 6 and 7, and both surfaces of the wafer are polished while supplying an abrasive to the polishing surface.

  By polishing in this way, it is possible to suppress the deterioration of the chamfered shape of the wafer and the generation of scratches in the wafer surface or in the chamfered portion while preventing damage to the peripheral edge of the wafer. Thereby, the product yield can be improved.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples of the present invention, but the present invention is not limited to these.

(Example 1-3)
Using a double-side polishing apparatus as shown in FIG. 1 having a double-side polishing apparatus carrier as shown in FIG. 3, 200 silicon wafers having a diameter of 300 mm were double-side polished according to the double-side polishing method of the present invention. The material of the resin ring of the carrier for the double-side polishing apparatus is a wholly aromatic liquid crystal polyester resin (Example 1), an allyl resin (Example 2), and a wood powder-filled phenol resin (Example 3), and after polishing in each case The shape of the peripheral portion of the wafer and the occurrence rate of scratches in the in-plane and chamfered portions were evaluated.

Here, at the time of producing the carrier for the double-side polishing apparatus, a tensile test of each material used for the resin ring was performed, and the tensile elastic modulus was measured.
This tensile modulus is measured based on a tensile test in accordance with ASTM D638. The tensile tester keeps the moving speed of the crosshead constant during the test and consists of a gripper, a load indicator, and an extensometer. We used what was to be done.

Moreover, the test piece used the dumbbell-shaped thing as a typical shape, and the tensile speed was 5 mm / sec. The tensile elastic modulus was calculated by the following formula using the first linear portion of the tensile stress-strain curve. Where E is the tensile modulus, σ is the difference in stress due to the original average cross-sectional area between two points on the straight line, and ε is the difference in strain between the same two points.
E = σ / ε

Also, the shape of the peripheral edge of the wafer is evaluated by the difference between the position of the outermost peripheral edge (center in the thickness direction of the wafer) of the wafer before polishing and the position of the portion deformed due to wear after polishing. Was performed using Taylor Hobson's LSM-3000.
Scratches were measured with KLA-TENCOR SURFSCAN SP-1.
The results are shown in Table 1. As shown in Table 1, in all of Examples 1-3, the difference in position described above is extremely small, that is, there is almost no change in the shape of the peripheral edge of the wafer, and the occurrence rate of scratches in the in-plane and chamfered portions is also sufficient. It is suppressed. This result was found to be improved compared to the results of Comparative Examples 1 and 2 described later.

FIG. 5 shows the measurement results of the shape of the peripheral edge of the wafer in Example 1. FIG. 5 shows the position plotted on the drawing with the peripheral edge of the wafer facing upward. As can be seen from FIG. 5, the peripheral edge of the wafer is hardly worn.
Further, no damage to the peripheral edge of the wafer occurred.
In this way, by performing double-side polishing using the carrier for a double-side polishing apparatus of the present invention, while preventing damage to the peripheral edge of the wafer, deterioration of the chamfered shape of the wafer and scratches (scratches) in the wafer surface or in the chamfered portion. It was confirmed that the occurrence could be suppressed.

(Comparative Example 1-3)
Example 1-3, except that the resin ring material of the carrier for a double-side polishing apparatus was aramid fiber reinforced epoxy resin (Comparative Example 1), polycarbonate resin (Comparative Example 2), and glass fiber reinforced epoxy resin (Comparative Example 3) The silicon wafer was polished on both sides under the same conditions as in Example 1-3 and evaluated in the same manner as in Example 1-3. Here, the tensile elastic modulus of the aramid fiber reinforced epoxy resin and the polycarbonate resin is 9.00 GPa, 2.38 GPa and less than 12 GPa, respectively, and the tensile elastic modulus of the glass fiber reinforced epoxy resin is 21.09 GPa and 20 GPa or more.

  The results are shown in Table 1. As shown in Table 1, in Comparative Examples 1 and 2 in which the tensile elastic modulus of the resin ring is less than 12 GPa, the wear on the peripheral edge of the wafer is greatly generated compared to Example 1-3, and the chamfered shape is deteriorated. It was found that the smaller the tensile modulus, the greater the deterioration of the shape. Further, it was found that in Comparative Examples 1 and 3 using a resin including a reinforcing material in the resin ring, scratches frequently occurred in the wafer surface and the chamfered portion. In Comparative Example 3, although the chamfered shape of the wafer is not deteriorated, scratches frequently occur in the wafer surface and the chamfered portion, and the yield is deteriorated.

6 and 7 show the measurement results of the shape of the peripheral edge of the wafer in Comparative Examples 1 and 2, respectively. 6 and 7 are the positions plotted on the drawing with the peripheral edge of the wafer facing upward as in FIG.
As shown in FIG. 6, in Comparative Example 1, it was confirmed that the peripheral edge of the wafer was deformed due to wear and was concave toward the inside of the wafer. Further, as shown in FIG. 7, in Comparative Example 2, it was confirmed that the wafer was greatly deformed into a concave shape toward the inside of the wafer.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has any configuration that has substantially the same configuration as the technical idea described in the claims of the present invention and that exhibits the same effects. Are included in the technical scope.

DESCRIPTION OF SYMBOLS 1 ... Carrier for double-side polishing apparatus, 2 ... Resin ring, 3 ... Carrier matrix,
4 ... holding hole, 5 ... polishing cloth, 6 ... upper surface plate, 7 ... lower surface plate, 8 ... chamfered portion,
9 ... Sun gear, 10 ... Internal gear, 20 ... Double-side polishing machine, W ... Wafer.

Claims (4)

  A carrier for a double-side polishing apparatus in a double-side polishing apparatus that polishes both surfaces of a wafer having a chamfered portion at the periphery, and is disposed at least between upper and lower surface plates to which a polishing cloth is attached, and the upper and lower surfaces are fixed during polishing. A carrier base in which a holding hole for holding the wafer sandwiched between the boards is formed, and an inner circumference of the holding hole of the carrier base, and is in contact with a chamfered portion of the held wafer. A ring-shaped resin ring that protects the chamfered portion, and the resin ring has a tensile elastic modulus based on a tensile test based on ASTM D638 of 12 GPa or more and 20 GPa or less, and does not contain an inorganic reinforcing material. A carrier for a double-side polishing apparatus, characterized by comprising:   2. The resin ring according to claim 1, wherein the resin ring is made of any one of wood powder-filled phenol resin, chipped roving-filled unsaturated polyester resin, polyamideimide resin, allyl resin, and wholly aromatic liquid crystal polyester resin. The carrier for double-side polishing apparatus as described.   A double-side polishing apparatus comprising at least the carrier for a double-side polishing apparatus according to claim 1 or 2.   A method for double-side polishing a wafer, wherein the carrier for a double-side polishing apparatus according to claim 1 or 2 is disposed between upper and lower surface plates to which a polishing cloth is attached, and an inner periphery of a holding hole of the carrier A resin ring made of a resin having a tensile modulus of elasticity of 12 GPa or more and 20 GPa or less and a chamfered portion of the wafer placed in contact with each other and held by the chamfered portion of the wafer, and the wafer is sandwiched between the upper and lower surface plates A double-side polishing method for a wafer, characterized in that the double-side polishing is performed with a wafer.

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