JPH0350847A - Holding tool for wafer handling - Google Patents

Abstract

PURPOSE:To obtain a holding tool such as a bracket or the like which is chemi cally stable and whose dimensional accuracy and stability are high by performing injection-molding of a polyallylene sulfide resin represented by a polyphenylene sulfide resin. CONSTITUTION:A holding tool 1 for wafer handling use is formed by injection- molding a material which is composed mainly of a polyallylene sulfide resin and with which small mounts of other resins have been mixed within a range not obstructing its object. Its shape is of a basket type which can align and hold many wafers 3 in a noncontact manner, which can insert and take out them smoothly and in which not only the upper part but also the bottom or side faces are open; it is preferably a structure form which is provided with ribs 2 or the like so as to fit the wafers accurately.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to baskets, containers, and other holders used in various processing, cleaning, transportation, storage, and other handling of wafers used in the semiconductor industry. It is.

[Conventional technology and its issues]

Semiconductor wafers such as silicon wafers used in the semiconductor industry are generally very brittle and easily damaged, and require processing under extremely harsh conditions for processing and other handling. For example, in the preparation process, highly corrosive processing liquids (cleaning liquids) at high temperatures, such as strong acids, strong alkalis, hydrofluoric acid, ammonium fluoride,
Contact treatment with other solvents, etc., and treatments such as high-temperature dry smoke and centrifugal deliquification are also performed. Therefore, for these processes, unlike the handling of general plate-shaped objects, for efficiency, it is necessary to set a large number of wafers in a specific holder in a basket shape or other shape that aligns and holds them. It is necessary to carry out handling as described above, and such holders must be made of a material that has strong chemical resistance, especially against corrosive liquids at high temperatures, as well as thermal and mechanical resistance. Because the wafers are fragile, easily damaged, and prone to scratches and abrasion, the holder must be able to hold a large number of wafers without touching each other, and the holder must be able to hold the wafers accurately. It is necessary to store and hold the device in such a way that it is not subjected to shocks due to vibrations, and it is not preferable to tighten a portion of the device in order to avoid vibrations, as this may cause damage. To this end, holders such as baskets and containers for holding and accommodating wafers must have accurate shapes and dimensions.

Conventionally, holders such as baskets used for this purpose are made of fluorine-based resins, such as polytetrafluoroethylene or copolymer resins of its type, due to their chemical stability against processing liquids. However, the resin itself is expensive, has poor molding processability and molding efficiency, and is prone to mold shrinkage and shape changes due to heating, making it difficult to inject holders such as baskets with precise shapes. It is difficult to obtain this by molding, and due to the lack of dimensional accuracy, it is difficult to set the wafer smoothly and without rattling due to vibration, and some storage locations may not fit smoothly. In some cases, some storage locations are too loose, resulting in defects such as unavoidable vibration. For this reason, it is necessary to increase the dimensional accuracy and correct the shape accuracy by cutting after forming, which is not only extremely uneconomical in manufacturing, but also causes deformation due to distortion during forming during high temperature processing, making it difficult to take out. This is not desirable because it causes problems. Additionally, attempts have been made to use more expensive materials such as polyetheretherketone (PEEK), but these also have the same problems as mentioned above in terms of non-economic aspects, and are not fully satisfactory. I can't say that.

[Means to solve the problem]

The present inventors do not have the drawbacks of the conventional wafer handling holders, and have achieved the required performance, that is, resistant to harsh chemical processing solutions, such as strong acids such as hydrofluoric acid and sulfuric acid, strong alkalis, and special solvents. As a result of repeated studies on materials that are chemically stable and that can be efficiently obtained as they are by injection molding into holders such as baskets that have a high degree of dimensional accuracy and stability, we have developed materials such as polyphenylene sulfide resin (PPS). We have discovered that polyarylene sulfide resin (PAS) satisfies all of the above requirements, and have arrived at the present invention.

That is, the present invention uses polyarylene sulfide resin (PA
The present invention provides a wafer handling holder consisting of S).

The PAS used in the present invention is a main repeating unit +Ar
-3-)- (where Ar is an arylene group).

As the arylene group, for example, polyphenylene sulfide resin (abbreviated as PPS) consisting of a phenylene group such as Although preferred, f'+ p'-diphenylene sulfone group p, p-diphenylene ether group p, p-diphenylenecarbonyl group, etc. can also be used.

In this case, it is preferable to use a polymer using the same repeating units, that is, a homopolymer, among the arylene sulfide groups composed of the above-mentioned arylene groups, but from the viewpoint of moldability, different types of repeating units are used as an aid. In some cases, copolymers containing small amounts of carbon are preferred.

As the homopolymer, a substantially linear PPS having a p-phenylene sulfide group as a repeating unit and using a p-phinidine group as an arylene group is particularly preferably used.

Further, as a copolymer, a combination of two or more different types of arylene sulfide groups consisting of the above-mentioned arylene groups can be used, but among them, a combination containing a p-phenylene sulfide group and a m-phenylene sulfide group is particularly preferably used. . Among these, those containing p-phenylene sulfide groups in an amount of 50 mol% or more, preferably 70 mol% or more, are preferred in terms of physical properties such as chemical stability (corrosion resistance) to treatment liquids, heat resistance, moldability, and mechanical properties. Appropriate.

The PAS used in the present invention, especially PPS, can also be a polymer obtained by curing by oxidative crosslinking or thermal crosslinking, but it is preferable to obtain it by condensation polymerization from a bifunctional monomer, and even if it is heat-treated, the degree of crosslinking is but.

It is a polymer with a low, substantially linear molecular structure.

Among them, the melt viscosity measured under the conditions of a temperature of 310°C and a shear rate of 5/sec is 1 x 10 to 5 x 10' poise, preferably 50 to 5 x 10' poise, particularly preferably 100 to 5 x
Linear polymers in the 10' poise range are suitable.

If it is less than 10 poise, the fluidity will be too good and melt processing will be difficult, and even if a molded product is obtained, the mechanical strength will be low, which is undesirable. Moreover, those having more than 5×105 voids have poor fluidity and are difficult to melt process.

Generally, PAS, especially PPS, is widely used as engineering plastics by blending glass or other inorganic fibrous, powder, or plate-like fillers. These fillers are known to have useful effects, and the use of these fillers as materials in the present application is not excluded as long as they do not impede the purpose; however, such fillers generally contain strong acids, strong alkalis, and especially The holder for handling wafers of the present invention, which comes into contact with highly corrosive chemicals such as hydrofluoric acid and ammonium fluoride, is often unsuitable because these fillers are corroded. Also unfilled PAS, especially PP
It is often preferred to use S as the material. As unfilled PAS, its mechanical strength, elongation,
PAS, which has a substantially linear molecular structure in terms of toughness, etc.
In particular, it is advantageous to use linear PPS.

The material for the holder for handling wafers in the present invention may be mainly composed of PAS as described above, with a small amount of other resins added thereto as long as the purpose is not impaired.

The shape of the wafer handling holder of the present invention is not particularly limited, but it may be a basket rattle or a container that can hold a plurality of (as many as possible) wafers apart and aligned without contacting them. Particularly when the purpose is liquid processing, cleaning, etc., a basket type is preferable, in which not only the wafer can be smoothly inserted and removed, but also the bottom or sides are open as well as the top. Preferably, the structure is such that ribs or the like are provided to prevent the wafer from vibrating and to ensure an accurate fit.

Examples thereof are shown in FIGS. 1 and 2, but the shape of the wafer handling holder of the present invention is not limited to this. Here, FIG. 1 (1) is a perspective view of a wafer handling holder according to an embodiment of the present invention, FIG. 1 (2) is a plan view, and FIG.
) is a schematic cross-sectional view taken along the line I-I' of (2), and is shown in Figure 2.
1 is a perspective view of a wafer handling holder according to another embodiment of the present invention; FIG.

Next, the manufacturing method of the wafer handling holder of the present invention can be efficiently and easily molded using the above-mentioned materials by a general injection molding method, and the conditions are also similar to those of general PAS and PPS.
Settings can be made in accordance with the case of injection molding. That is, for example, the resin temperature is 290 to 350°C, and the mold temperature is 90 to 16°C.
It is appropriate to set the temperature to 0°C.

By using PAS, especially PPS, which is a feature of the present invention, as the material for the wafer handling holder, it is possible to make it thinner and lighter than conventional materials, and the dimensional accuracy is also good, so it is generally particularly suitable for molding. Although it is not necessary to carry out the subsequent cutting process, it is of course possible to perform the cutting process if special high-precision dimensions are required.

〔Example〕

Examples are given below, but the present invention is not limited thereto.

Example 1, Comparative Example 1.2 In order to compare the suitability as a holding material for wafer handling, unfilled linear polyphenylene sulfide (PPS) was used.
(Polyplastics Co., Ltd. “Fortron”) (
Using Example-1), conventionally used polytetrafluoroethylene copolymer (PFA) (Comparative Example-1), and polyetheretherketone (PEEK) (Comparative Example-2), a certain test mold was prepared. Test specimens were created using the following methods, and relative comparative evaluations were made regarding optimal molding conditions, molding cycles, mold shrinkage rates, chemical resistance, and other required properties.

The results are shown in Table 1.

From the relative comparison in the table above, PPS is the conventionally used PFASPEE.
It can be seen that this material is superior to K in various required performances as a wafer handling holder.

Example 2, Comparative Example 3, Comparative Example 4 Using the same materials as those used in the above Examples and Comparative Examples, wafer baskets as shown in Figure 1 were molded by injection molding under appropriate conditions. The required molding cycles were then measured.

Further, it was heat-treated at 200°C for 2 hours, and the dimensional accuracy was measured as follows.

1. Warp deformation of side plate A section (macroscopic observation) 2. Straightness of rib plate 8 section (〃) 3. Insert the wafer to be held between each rib,
The smoothness of wafer insertion and removal, and the degree of rattling were examined.

The results are shown in Table 2.

Table 2 [Effects of the Invention] As is clear from the above explanation and examples, the PAS of the present invention
Compared to conventionally used wafer handling holders made from PFAXPEEK, there is no need to set the resin temperature or mold temperature to abnormally high temperatures during injection molding, and it also has good fluidity. In particular, it can be molded without increasing the gate size, has a fast solidification rate, and can be manufactured efficiently by shortening the molding cycle. Furthermore, it is possible to make the material thinner and lighter, it has excellent dimensional accuracy, and there is little deformation due to heat treatment, and sufficient shape precision can be obtained by injection molding without any particular cutting process. It is also chemically stable against various chemicals used in wafer processing, making it suitable as a holder for handling wafers.

[Brief explanation of drawings]

Figure 1 (1) is a perspective view of a wafer handling holder according to an embodiment of the present invention, Figure 1 (2) is a plan view, and Figure 1 (3) is a perspective view of a wafer handling holder according to an embodiment of the present invention.
), and FIG. 2 is a perspective view of a wafer handling holder according to another embodiment of the present invention. Side plate side rib plate bottom rib plate holder main body rib wafer cavity

Claims (1)

[Claims] 1 Polyarylene sulfide resin A wafer handling holder characterized by: 2 Polyarylene sulfide resin is essentially It has an uncrosslinked linear molecular structure. The wafer handling holder according to claim 1. 3 Polyarylene sulfide resin is Claim 1 or phenylene sulfide is the wafer handling holder described in 2. 4 Using polyarylene sulfide resin Characterized by molding by injection molding Method for manufacturing wafer handling holders.