JPH09207064A - Carrier for double side polisher and method for polishing both faces of work using the carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the occurrence of a trouble, such as metallic pollution by a method wherein when the both faces of, for example, a semiconductor substrate are polished, the strength of a carrier to hold a substrate is ensured. SOLUTION: A number of small holes 6,... are formed in an Sk material being the core of a carrier 1 or a metallic core 2, such as an SUS material. Resin coats 3 are formed on both faces of the metallic core 2 and the small holes 6 are also filled with resin, and the peel strength of the resin coat 3 is improved by firmly combining together the resin coat 3 on the surface side and the resin coat 3 on the back side. Further, the diameters of the small holes 6,... are set to 10mm ϕ or less. By using a so formed carrier, a work is polished.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a carrier for holding a semiconductor substrate when polishing both surfaces of the semiconductor substrate.

[0002]

2. Description of the Related Art Conventionally, for example, when polishing both surfaces of a semiconductor substrate by polishing or the like, the semiconductor substrate is held by a carrier. That is, this carrier is formed to have a thickness smaller than that of the semiconductor substrate, is configured to be held at a predetermined position between the upper platen and the lower platen of the double-side polishing machine, and has a substrate holding hole. Then, the semiconductor substrate is inserted and held in this substrate holding hole, and the upper and lower surfaces of the semiconductor substrate are sandwiched by a polishing tool such as a polishing cloth provided on the facing surface of the upper surface plate and the lower surface plate, and the polishing liquid is supplied to the polishing surface. While trying to polish.

By the way, as such a carrier, for example, a carrier made of resin, or a metal plate having front and rear surfaces coated with resin is generally well known. In the former case, a fiber-reinforced resin is usually used in many cases, and in the latter case, a resin layer is formed by spray-coating the resin on the surface of the metal plate or adhering a resin film.

[0004]

However, since the carrier is subjected to a load during polishing, there is a problem that the former one made of resin in particular tends to lack strength and is easily broken. In addition, if the resin layer is simply adhered to the surface of the metal plate as in the latter case, the resin layer is easily peeled off during polishing, and if the metal plate is exposed, a fatal defect for the semiconductor substrate such as metal contamination may occur. There was a problem that the yield of the product was deteriorated.

Therefore, there has been a demand for a carrier that is strong and does not cause problems such as metal contamination.

[0006]

In order to solve the above problems, the present invention provides a carrier for holding a work piece when polishing both sides of the work piece according to claim 1, which comprises a metal plate core. In a carrier for a double-sided polishing machine in which a resin layer is formed on the front and back surfaces, a large number of small holes are bored in a metal plate core, and resin is filled in the small holes to bond the resin layers on the front and back surfaces. I chose Further, in claim 2, the diameter of the small hole is 10
It was set to mmφ or less.

When the metal plate is used as the core material in this way, the strength against the load applied during polishing is sufficient,
In addition, if a large number of small holes drilled in the metal plate core are filled with resin and the resin layer on the front surface side and the resin layer on the back surface side are bonded together, the peel strength of the resin increases and the situation of metal exposure can be avoided. I can. At this time, if the diameter of the small holes is 10 mmφ or less, the bonding strength of the resin layers on the front and back surfaces can be increased, and the rigidity of the metal plate core is not impaired.

Therefore, if both surfaces of the workpiece are polished by using the carrier according to claims 1 and 2, it is possible to stably polish the workpiece without fear of metal contamination. Therefore, this is the invention of claim 3 of the present invention.

[0009]

Embodiments of the present invention will be described with reference to the accompanying drawings. Here, FIG. 1 is a vertical cross-sectional view for explaining the structure of the double-side polishing machine, FIG. 2 is an internal structure view in plan view, FIG. 3 is a plan view showing an example of a metal plate core serving as a core material of a carrier, and FIG. FIG. 4 is a cross-sectional model view of a carrier. The carrier for a double-sided polishing machine of the present invention relates to an improvement of a carrier for holding a semiconductor substrate in a double-sided polishing machine for mirror-finishing both sides of a thinly sliced semiconductor substrate, for example. Will be described with reference to FIGS. 1 and 2.

The double-sided polishing machine 10 comprises a lower surface plate 11 and an upper surface plate 12 which are vertically opposed to each other.
Polishing cloths 11a and 12a are attached to the facing surfaces of the Nos. 1 and 12, respectively, and the respective surface plates 11 and 12 are rotatable about a central axis by a drive source (not shown).

A sun gear 13 is provided in the central portion between the lower turn table 11 and the upper turn table 12, and a tooth portion of an internal gear 14 faces the peripheral edge of the sun gear 13. The outer peripheral teeth of the disk-shaped main carrier 1 are meshed with the respective tooth portions of the tooth gear 14. A plurality of substrate holding holes 4 to be described later are formed in the carrier 1, and a semiconductor substrate W thicker than the thickness of the carrier 1 is inserted and set in the substrate holding holes 4, and then the semiconductor substrate W is placed on the lower surface plate 11 and the upper platen 11. The carrier 1 is sandwiched between the surface plate 12 and the sun gear 13 and the internal gear 14.
Is rotated and revolved, the lower surface plate 11 and the upper surface plate 12 are rotated in a relative direction, and the polishing cloths 11a and 12a are used for polishing.

At this time, as shown in FIG. 1, the polishing liquid is supplied from the nozzle 15 on the upper surface plate 12 and sent to the polishing surface through the through holes 16 provided in the upper surface plate 12. Incidentally, the carrier 1 is provided with a polishing liquid hole 5 described later, and the polishing liquid is evenly supplied to the polishing surface on the lower surface side through the polishing liquid hole 5.

The carrier 1 is formed by covering the entire circumference of a metal plate core 2 as shown in FIG. 3 with a resin coat 3 as shown in FIG. The peel strength is increased. The metal plate core 2 has a disk shape with teeth G, ... Formed on the outer periphery, and the plate thickness of the metal plate core 2 is about 80 to 90% of the desired thickness of the carrier 1. The material is a metal such as SK material or SUS material.

Further, the metal plate core 2 has a large number of substrate holding holes 4 into which the semiconductor substrate W is inserted, a medium diameter polishing liquid hole 5 for passing a polishing liquid, and a large number of holes. Small hole 6, ...
Are provided as through holes, and the diameters of the substrate holding holes 4, ... Are formed in accordance with the diameter of the semiconductor substrate W. In the embodiment, the substrate holding holes 4 ,.
At the same time, three semiconductor substrates W, ... Can be held.

The small holes 6, ... Have a diameter of 10 mmφ or less, and in the embodiment, about 5 mmφ-10 mmφ. Further, the interval between the small holes 6, ... Is preferably different depending on the material of the resin and the like, but is suitably about 5 to 10 mm, for example.

A resin coat 3 is coated on the front and back surfaces of the metal plate core 2 as described above. At this time, the substrate holding holes 4, ... And the polishing liquid holes 5, ... Are covered with the resin coat 3 only on the inner peripheral end faces to maintain the through state of the holes, and the small holes 6 ,. The inside is filled with resin to form a blind hole. Therefore, the resin coat 3 on the front surface side and the resin coat 3 on the back surface side are in a state of being bonded by the resin in the small holes 6, ..., And firmly adhere to the surface of the metal plate core 2.

The resin coat 3 as described above is formed by injecting a heat-melted resin toward the front and back surfaces of the metal plate core 2 by molding and filling the small holes 6, ... Alternatively, a thermosetting resin film may be adhered to the front and back surfaces of the metal plate core 2 and heated and pressed to fill the resin into the small holes 6 ,. You may make it bond the resin of the front and back. Then, the entire outer surface of the metal plate core 2 is covered with the resin coat 3 to eliminate the metal exposed portion. Here, as the material of the resin used, it is necessary to have excellent workability and moldability,
For example, polyimide, polyamide, polyethylene, polypropylene, polyacetal and the like are suitable. The carrier 1 as described above is made thinner than the thickness of the semiconductor substrate W.

In the carrier 1 constructed as described above, when the semiconductor substrate W is inserted and held in the substrate holding hole 4, the upper and lower surfaces of the semiconductor substrate are sandwiched by the upper surface plate 12 and the lower surface plate 11 of the double-side polishing machine. Be done. Then, while supplying the polishing liquid to the polishing surface, the polishing process is performed while rotating the upper surface plate 12 and the lower surface plate 11 in a relative direction. On this occasion,
For example, the polishing liquid supplied to the upper surface of the semiconductor substrate W spreads evenly to the lower surface through the polishing liquid holes 5, ....

The force applied to the carrier 1 during the polishing is usually 500 g / cm ² or more, though it depends on the polishing conditions. However, in the case of the present invention, the metal plate core 2 has sufficient strength to withstand the above-mentioned load, and the resin coat 3 covering the outer surface of the metal plate core 2 is firmly bonded by the resin in the small holes 6 ,. Therefore, the resin coat 3 is difficult to peel off. Therefore, the semiconductor substrate is not contaminated with metal.

By the way, FIG. 5 shows experimental values comparing the carrier of the present invention with the conventional carrier. Here, the conventional example is made of epoxy glass in which glass fiber is impregnated with epoxy resin, and SK + resin film in which resin is coated (film) on the surface of SK material. Both are polished for a total of 20 hours under constant polishing conditions. Then, the durability time (vertical axis) was examined.

As a result, in the epoxy glass carrier, the tooth portion G was broken in about 0.5 hours, and in the case of the SK + resin film, the film peeled off in about 5 hours. On the contrary, in the case of the present invention, no change was observed even after polishing for 20 hours. From this result, the effectiveness of this plan was confirmed. Although the small holes 6, ... Have a circular shape in the embodiment, it goes without saying that other shapes are also effective.

[0022]

As described above, in the carrier for a double-sided polishing machine of the present invention, a large number of small holes are formed in the core of a metal plate as a core material, and a resin is placed in the small holes. Since the resin layers formed on the front and back surfaces by filling are bonded to each other, it is possible to secure sufficient strength to withstand the load applied during polishing and to firmly bond the resin layers on the front and back surfaces. Therefore, metal exposure can be suppressed, and problems such as metal contamination can be avoided. Further, in claim 2, the diameter of the small hole is 1
Since the diameter is 0 mm or less, the resin layers on the front and back surfaces can be firmly bonded without impairing the rigidity of the metal plate core. Therefore, if both surfaces of the workpiece are polished by using the carrier according to the first and second aspects, it is possible to stably polish the workpiece without worrying about metal contamination.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view for explaining the structure of a double-side polishing machine.

FIG. 2 is a plan view of an internal structure of the double-sided polishing machine.

FIG. 3 is a plan view showing an example of a metal plate core serving as a core material of a carrier.

FIG. 4 is a sectional model view of a carrier.

FIG. 5 is a result diagram of a durability test of the carrier of the present invention and the conventional carrier.

[Explanation of symbols]

1 ... Carrier, 2 ... Metal plate core, 3
… Resin coat, 4… Substrate holding hole, 5…
Polishing liquid hole, 6 ... Small hole, 10 ... Double side polishing machine, 11 ... Lower surface plate, 11a ... Abrasive cloth, 12 ... Upper surface plate, 12a ... Abrasive cloth,
13 ... Sun gear, 14 ... Internal gear, 1
5 ... Nozzle, 16 ... Through hole, G ... Tooth portion, W ... Semiconductor substrate.

Front page continued (72) Inventor Hideo Kudo Ogokura, Ogokura, Nishigomura, Nishishirakawa-gun, Fukushima 150 Shin-Etsu Semiconductor Co., Ltd. Semiconductor Shirakawa Research Center

Claims (3)

[Claims] 1. A carrier for holding a work piece when polishing both sides of the work piece, wherein a carrier for a double-sided polishing machine is such that a resin layer is formed on the front and back surfaces of a metal plate core. A carrier for a double-sided polishing machine, characterized in that a large number of small holes are formed in a metal plate core, and the small holes are filled with resin to bond the resin layers on the front and back surfaces. 2. The carrier for a double-sided polishing machine according to claim 1, wherein the diameter of the small holes is 10 mmφ or less. 3. A method for polishing both sides of a workpiece, which comprises using the carrier for a double-sided polishing machine according to claim 1 or 2.