JPH06181157A - Apparatus with low dust-generating property - Google Patents

Abstract

PURPOSE:To provide an apparatus with low dust-generating properties, which is used in a clean room to suppress the generation of very fine particles and improved in dust-wiping properties by a clean wiper, etc. CONSTITUTION:The attraction parts 12 of a carrier arm 11 for vacuum- attracting and carrying a silicon wafer 13 are formed by one material selected from a group of materials having mutual wear and abrasion resistance, in which the materials neither wear the silicon wafer 13 nor are worn by the wafer 13, and high dust-wiping properties by a wiper, etc., e.g. polyacetal resin, polyether-imide resin, polyamide resin, polyamide-imide resin and poly- butyleneterephthalate resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus having low dust generation suitable for use in a transfer mechanism of an exposure apparatus or an inspection apparatus used in a clean room such as a semiconductor.

[0002]

2. Description of the Related Art The conventional low dust generation technology is lubricated between members in order to suppress the generation and scattering of wear powder (fine surface damage) due to frictional wear caused by sliding and contact between members. Applying oil, coating a hard thin film to harden one or both of the members, or a solid lubricating film to reduce the friction coefficient and increase wear resistance,
By achieving durability, the effect of low dust generation is exhibited.

[0003]

In recent years, the line width of integrated circuits in semiconductor manufacturing has become thin, and 0.5 μm at 16 M-bit,
It is said to be 0.35 μm for 64M-bit, 0.25μm for 256M-bit, and 0.15μm for 1G-bit. Along with this, the demand for a cleaner environment for the semiconductor manufacturing is also increasing. In particular, contamination of the wafer surface with fine particles (dust) in the semiconductor manufacturing environment is a serious problem such as deterioration of product yield. However, the above-mentioned conventional technique is to improve the wear resistance of one or both members that come into contact with each other as described above, and does not realize complete wear-free. Therefore, fine abrasion powder generated due to contact between members adheres to the surfaces of both members or scatters around them. That is, the above-mentioned conventional techniques cannot realize a high degree of cleanliness on the wafer surface or the semiconductor manufacturing environment.

An object of the present invention is to be used in a clean room, to suppress the generation of fine particles, to suppress the adhesion of the fine particles to the surface of a work represented by a wafer, and to keep the inside of the clean room. An object of the present invention is to provide a device with low dust generation capable of suppressing the scattering of fine particles.

[0005]

The present invention will be described with reference to FIG. 1 showing an embodiment. The present invention is applied to a low dust generating device for processing a work in a clean room, and the work 13 is By forming the part 12 in sliding contact with the work piece 13 by one material selected from a group of materials having mutual wear resistance and high cleaning property, Achieve the purpose. In the apparatus according to claim 2, when the workpiece 13 is a silicon wafer, the materials having mutual abrasion resistance are materials in which the number of fine particles generated when sliding on each other is at least three digits smaller than that of alumina. A material having a high wiping cleanability is a material having a better wiping cleanability than at least alumina. In the apparatus of claim 3, the group of materials is a polyacetal resin, a polyetherimide resin, a polyamide resin, a polyamideimide resin, and a polybutylene terephthalate resin. In the apparatus of claim 4, the group of materials is a fluororesin, a polyether resin, a polyolefin resin and a polyphenylene sulfide resin.
In the device of claim 5, the group of materials is a material close to the positive side or negative side end of the charging train. Claim 6
In the above device, when the work is a semiconductor wafer or a glass substrate, the device for processing the work is tweezers, a transfer mechanism, or a centering mechanism. In the apparatus according to claim 7, the part which the silicon wafer contacts is vacuum tweezers, a transfer mechanism, or a centering mechanism.

[0006]

For example, when the work 13 is carried by the carrying device of the semiconductor manufacturing apparatus, even if the work 13 comes into sliding contact with the suction portion 12 or the like, generation of abrasion powder is suppressed. In addition, since the portion 12 has a high wiping cleanability, dust and the like on the surface can be wiped off well when it is wiped and cleaned by a clean wiper or the like.
As a result, a device with low dust generation can be provided.

-Evaluation Test 1-First, the inventors of the present invention used a pin-on-disc type friction and wear test with a combination of a silicon wafer 1 having a diameter of 2 inches and a spherical pin 2 having a diameter of 10 mm made of various materials as shown in FIG. (load
100gf, friction speed 50mm / s) was performed, and the difference in the amount of dust generation was compared. Fine particles (wear particles) generated and scattered due to wear of the silicon wafer 1 or pins 2 are sucked at a suction flow rate of 1 cubic foot per minute with a suction nozzle 3, and a laser particle counter (Met-One A249 type) is used. The number of fine particles (particle size 0.1 μm or more) was measured. The results are shown in FIGS.

As shown in FIG. 3, when the pin 2 contacting the silicon wafer 1 is a ceramic sphere (for example, silicon nitride or alumina), the silicon wafer side is scraped more than the ceramic side and the abrasion powder is scattered. It showed dusting. When the pin 2 is a metal ball (for example, high carbon chrome steel) or a quartz glass ball, both the silicon wafer 1 and the pin 2 are worn and dust is generated. However, when the pin 2 is a plastic sphere such as polyetheretherketone, polyetherimide, polyacetal (trade name Delrin), polyethylene, or polyphenylene sulfide, both the silicon wafer 1 and the pin 2 have little wear and show low dust generation. . However, in the case where the pin 2 was a ball of polytetrafluoroethylene (trade name Teflon), the pin 2 side was worn, but the abrasion powder was difficult to scatter and was not measured by the laser particle counter.

As described above, it is necessary to use a material having excellent wear resistance for each part of the device of low dust generation that comes into contact with a work such as a silicon wafer. Scattering of wear particles is not preferable. On the contrary, it should not be a material that is worn by the work.
Therefore, by using the above-described plastic that does not wear the work and is not worn by the work, it is possible to suppress the wear of the work and the part in contact with the work, and to provide a device with low dust generation. In this specification,
Materials having such wear characteristics are called materials having mutual wear resistance.

As described above, the polyacetal resin, the polyetherimide resin, the polyamide resin, the polyamideimide resin, the polybutylene terephthalate resin, and the like are compared with alumina and the like in the above-described pin-on-disc type abrasion friction test. Generated abrasion powder is 3
It can be suitably used as the above-mentioned materials having mutual wear resistance, which are less than the order of magnitude.

-Evaluation Test 2- Next, the inventors compared the transferability of fine particles (such as dust generated from the wiper) to the silicon wafer due to contact between the silicon wafer and various materials. Prior to the test, the surface of a silicon wafer having a diameter of 4 inches is cleaned to remove as much as possible fine particles adhering thereto. On the other hand, a flat substrate having a diameter of 50 mm was used as a member to be brought into contact with the silicon wafer, and the surface thereof was wiped with a known wiper for a clean room in which a polar solvent (eg isopropyl alcohol) was soaked. After a flat substrate is placed on a silicon wafer and brought into contact with it with a constant load, the degree of adhesion of fine particles on the surface of the silicon wafer is determined by a laser scattering dust inspection machine (SURFSCAN
# 4500). The result is shown in FIG.

The surface of the flat substrate before wiping and cleaning is a mechanically optically polished surface that has been precisely cleaned, and the degree of contamination on the surface of the test material may vary depending on the material, but next several times. The difference can be ignored because the wiper is wiped across. Moreover, the difference in the surface roughness did not have a great influence on this evaluation. Since it was wiped with a wiper impregnated with a polar solvent, the surface of the flat substrate was difficult to be charged regardless of the difference in the substance, and the charging voltage was within ± 0.5 kV.

When the wiper cleaning of the surface of the portion where the silicon wafer comes into contact is manually performed in the clean room, there may be a difference in the cleaning property due to the difference in the surface free energy (surface tension) of the substance. That is, the substance having excellent wiping cleanability has a better surface cleanness than the substance having no such property. In semiconductor manufacturing, the surface of a carrier that comes into contact with a workpiece such as a silicon wafer needs to be cleaned with a clean wiper or the like during maintenance of the carrier or at regular intervals. Considering this actual work,
It is realistic to evaluate the transferability including the cleanability of the surface of the flat substrate.

As can be seen from FIG. 5, polytetrafluoroethylene (Teflon), polyetherimide and polyacetal have less transferability of fine particles to a silicon wafer than quartz glass, silicon carbide or alumina. That is, the material of the part where the workpiece contacts is close to the end of the charging column on the positive side, such as polyacetal (Delrin), polyetherimide, polyamide (nylon), or the end of the charging column on the negative side. When formed of substances such as polytetrafluoroethylene (Teflon), polyetheretherketone, polyethylene, etc., these materials are substances close to the positive and negative polarity side ends in the charging train and are easily charged by contact, so that fine particles are not I think that it is difficult to transfer to a wafer.

As described above, by using a material close to the positive side or the negative side of the charging train as the material of the portion in which the silicon wafer is in sliding contact, the generated abrasion powder or its floating in the environment. The generated dust tends to adhere to the side of the member made of a substance close to the positive side or negative side end of the charging column. As a result, if the mating member is a wafer,
Adhesion of fine particles such as abrasion powder and dust can be suppressed on the wafer contact surface. Such a characteristic that the material is close to the positive side or negative side of the charging line and has good wiping cleanability is referred to as high wiping cleanability in this specification, and as can be seen at least from FIG. When the work is a silicon wafer, a material having a better cleaning property than that of alumina is suitable.

FIG. 6 shows "charge trains" of various materials. When two objects are contacted or rubbed, one is charged positively and the other negatively charged. When this is tested on many substances, a series of charged particles is formed by arranging from ones that are easily positively charged to those that are easily negatively charged in a row.

In order to realize low dust generation, even if the substance is close to the positive side or negative side of the charging train, the silicon wafer and the glass substrate are not abraded, and the silicon wafer and the glass substrate themselves are used. It is essential that they have mutual wear resistance so that they are not abraded by. The charging train of FIG. 6 and FIG.
From the figure of Fig. 4, it is shown in Fig.
It can be seen that all of the resin-based materials shown in (1) are materials whose charge train is on the positive electrode side or the negative electrode side. Further, from the charging train of FIG. 6 and the drawing of FIG. 5, it can be seen that in the highly wipeable resin material shown in FIG. 4, the charging train is a material on the positive electrode side or the negative electrode side. Therefore, the material used for the sliding contact portion with the work in the low dust generating device to which the present invention is applied can be selected from the group of ones in which the charging train is close to the positive electrode side or the negative electrode side.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an example in which the present invention is applied to a silicon wafer transfer apparatus. In the figure, a passage 11a is formed inside the vacuum suction type transfer arm 11,
Three suction portions 12 that communicate with the passage 11a are provided at the tip thereof. The suction portion 12 is made of one material selected from various materials having high wiping cleanability and mutual wear resistance as described above. Therefore, when the silicon wafer 13 is transferred, even if the silicon wafer 13 makes sliding contact with the suction portion 12 of the transfer arm 11, no abrasion powder is generated, and the suction portion 12 of the suction portion 12 is regularly or before the transfer operation. If the surface is wiped with a clean wiper to suppress the adhesion of fine particles on the surface, the surface of the silicon wafer 13 is always kept clean and the yield is improved.

FIG. 7 is a diagram showing an example in which the present invention is applied to vacuum tweezers. A passage 21 a is formed inside the vacuum tweezers 21, and a suction portion 22 communicating with the passage 21 a is provided at the tip of the tweezers 21. Like the suction portion 12 of the transfer arm 11, the suction portion 22 is also made of one material selected from various materials having high cleaning property and mutual wear resistance. Therefore, also in this case, it is possible to provide the vacuum tweezers with low dust generation.

FIG. 8 is a diagram showing an example in which the present invention is applied to a wafer positioning mechanism. Wafer rotary table 3
Three positioning arms 3 radially with respect to the axis of rotation of 0
1 is provided. The tip of the positioning arm 31 is formed of one material selected from various materials having high wiping cleanability and mutual abrasion resistance, like the suction portion 12 of the transfer arm 11. It is formed of a disk 32. Therefore, also in this case, the silicon wafer 13 is moved to the tip end disk 32 of the positioning arm 31 when the wafer is positioned.
Even if it comes into sliding contact with, it is possible to provide a positioning mechanism with low dust generation without generating abrasion powder as in the above.

The suction unit 1 shown in FIGS. 1, 7 and 8 is used.
Although 2, 22 and the disk 32 are made of the above-mentioned materials in their entirety, they may be coated on the surface in contact with the silicon wafer.

[0022]

As described in detail above, the materials selected from a group of materials having mutual wear resistance that neither the work wears nor the work wear, and which is excellent in wiping cleanliness. Since the work is made to form the part in which the work is in sliding contact, it is possible to suppress the adhesion of the fine particles to the work and the scattering of the fine particles to the environment where the work is used. It is possible to improve the reliability of a device in which scattering is a serious problem and to suppress deterioration of cleanliness of a clean environment in which the device is installed.

[Brief description of drawings]

FIG. 1 is a diagram showing an example in which the present invention is applied to a silicon wafer transfer arm.

FIG. 2 is a schematic diagram illustrating a method for measuring scattered fine particles by a pin-on-disk type friction and wear test in a combination of a silicon wafer and various materials.

FIG. 3 is a diagram showing the number of fine particles scattered when a friction and wear test is performed on a combination of a silicon wafer and various materials.

FIG. 4 is a diagram showing the number of fine particles scattered when a friction and wear test is performed using a combination of a silicon wafer and various materials.

FIG. 5 is a diagram showing the degree of adhesion of fine particles adhering to the surface of the silicon wafer by bringing various materials wiped with a solvent-impregnated clean wiper into contact with the silicon wafer.

FIG. 6 is a diagram showing a “charging sequence” related to static electricity of various materials.

FIG. 7 is a diagram showing an example in which the present invention is applied to vacuum tweezers.

FIG. 8 is a diagram showing an example in which the present invention is applied to a wafer positioning mechanism.

[Explanation of symbols]

 1 Silicon Wafer 2 Pins 3 Suction Nozzle 11 Transfer Arm 12 Adsorption Part 13 Silicon Wafer 21 Tweezers 22 Adsorption Part 31 Positioning Arm 32 Disk

Claims (7)

[Claims] 1. A low dust-generating apparatus for treating a work in a clean room, wherein a portion where the work slides and contacts has mutual wear resistance with the work and is highly cleaned. A low dust-generating device, which is formed of one material selected from a group of materials having properties. 2. The apparatus according to claim 1, wherein when the work is a silicon wafer, the mutually wear-resistant materials have a number of fine particles generated when they slide with each other of at least 3 digits compared to alumina. A low dust generating device, characterized in that the material having a small amount of cleaning material and having a high cleaning property is a material having a cleaning property which is at least better than that of alumina. 3. The apparatus according to claim 1, wherein the group of materials is a polyacetal resin, a polyetherimide resin, a polyamide resin, a polyamideimide resin, and a polybutylene terephthalate resin. Dust-generating device. 4. The low dust generating device according to claim 1, wherein the group of materials is a fluororesin, a polyether resin, a polyolefin resin, and a polyphenylene sulfide resin. 5. The low dust generating device according to claim 1, wherein the group of materials is a material close to a positive side or a negative side end of the charging train. 6. The apparatus according to claim 1, wherein the work is a semiconductor wafer or a glass substrate, and the device for processing the work is tweezers, a transfer mechanism, or a centering mechanism. A device with low dust generation, which is characterized in that 7. The low dust-generating device according to claim 2, wherein the portion in contact with the silicon wafer is vacuum tweezers, a transfer mechanism, or a centering mechanism.