JPH0878371A - Cleaning cassette for semiconductor wafer - Google Patents

Abstract

PURPOSE: To tightly support wafers in a cleaning cassette with reduced contact area of support faces of the cassette with the wafers by forming rows of support pins protrudent from the inner walls of the cassette in the length direction of the cassette along the circumferences of the wafers and contacting the top ends of the pins with the faces of the wafers. CONSTITUTION: Support pins 23a-23b and guide members 24 are protrudent from the both inner side walls of a main body 21 to its center; each wafer is supported with two right and two left pins and one right and one left members. Rows of the support pins and guide members are arranged in the length direction of the main body, each row supporting one wafer. The guide members in one row have grooves 24a to loosely receive the ends of the wafer held between the interiors of pair of grooves 24b located at the right and left of the guides. The outer circumferential faces of thin top ends of the support pins in each row contact with faces 2a of the wafer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a cleaning cassette used in a cleaning process of a semiconductor wafer (hereinafter sometimes abbreviated as a wafer) such as silicon or a III-V compound.

[0002]

2. Description of the Related Art In a semiconductor wafer manufacturing process, a cleaning process is an essential process for bridging each process.
In the wafer cleaning step, a means for housing the wafer in a cleaning cassette and cleaning the wafer in a cleaning tank has been conventionally used.

FIG. 8 and FIG. 9 show an example of a conventional wafer cleaning cassette. In the figure, 10 is a cleaning cassette, and 2 is a wafer which is an object to be cleaned. The cleaning cassette 10 is formed into a box-shaped body having an open upper surface and a lower surface, and a large number of wafer storage grooves 11 are arranged on the inner wall surface at equal intervals in the longitudinal direction. Reference numeral 13 is a rim for connecting the left and right cassettes.

When cleaning the wafer 2, the wafer 2 is fitted into each groove 11 through the upper opening 12 of the cassette 10 and the upper end flange 14 of the cassette is cleaned by a cleaning robot and a handle (not shown). The wafer 2 is washed by suspending it from the support and immersing it in a cleaning liquid in a cleaning tank (not shown).

At this time, the end face of the wafer 2 is formed in the groove 1
It is abutted on and supported by a large number of support surfaces 11a formed in the inside 1.

[0006]

However, since the semiconductor wafer 2 is usually a hard brittle substance and its surface is easily scratched, and a high processing precision is required, its end face is chamfered and further required. It is mirror-finished according to.
In addition, one main surface of a semiconductor wafer as a product is mirror-finished.

However, in the conventional cleaning cassette 10, the end face of the wafer 2 is supported in the groove 11 for inserting the wafer so as to be in contact with the supporting surface 11a formed in the groove 11. Therefore, the contact area between the wafer 2 and the supporting surface 11a of the cleaning cassette is large, and the mirror surface of the peripheral portion including the end surface of the wafer 2 is easily scratched and is more likely to be contaminated.

Further, the conventional cleaning cassette 10 is a PF
It is made of A (Per Fluoro Alcoxy fluororesins) resin material, but this PFA resin material has a heat distortion temperature of 75 ° C.
As low as (ASTM D648 / 0.45MPa load), the temperature in the cleaning tank may reach 80 ° C in a normal cleaning line, so that the cleaning cassette 10 is deformed with the lapse of use time, resulting in wafer support. The surface does not work properly.

Further, the PFA resin material is poor in abrasion resistance, and when the wafer is repeatedly taken in and out, particles such as abrasion powder adhere to the peripheral portion of the end surface of the wafer 2.

That is, in the conventional cleaning cassette 10, since the contact surface between the supporting surface 11a of the cassette 10 and the wafer 2 is large, scratches and stains easily occur on the peripheral portion of the end surface of the wafer 2, which results in high quality. However, there is a problem that it is difficult to stably obtain the wafer.

Therefore, it is an object of the present invention to firmly support a wafer in a cassette in a cleaning cassette used in a semiconductor wafer cleaning process while reducing the contact area between the supporting surface of the cassette and the wafer. The purpose of the present invention is to provide a cleaning cassette capable of preventing the generation of scratches and dirt on the surface of a wafer (particularly a mirror surface).

[0012]

In order to solve the above-mentioned problems, the present invention is an improvement of the wafer supporting portion of the cleaning cassette.

That is, the first feature of the present invention is that the cleaning cassette has a plurality of support pins projecting from the inner wall surface along the circumferential surface of the semiconductor wafer in a plurality of rows in the longitudinal direction of the cassette. The support pin is configured so that the peripheral surface of the end portion of the support pin is brought into contact with the plate surface of the wafer to support the wafer.

A second feature of the present invention is that the cleaning cassette has a plurality of support pins projecting from the inner wall surface along the circumferential surface of the semiconductor wafer in a plurality of rows in the longitudinal direction of the cassette, While making the end peripheral surface of the support pin contact the plate surface of the wafer, the wafer is loosely fitted in the groove of the guide member provided between the support pins, and the support pin and the guide member are used to It is configured to support the wafer. In this case, a pair of guide members having a groove portion between the support pins are arranged on both sides in the lateral direction of the cassette, and both end surfaces of the wafer are in contact with the inner ends of the groove portions of the guide member, and the depth of the wafer is increased. It is preferable to be configured so as to be supported in a state where the position is regulated in the direction.

A third feature of the present invention is that at least the guide member and the support pin have a thermal deformation temperature of 100 ° C. or higher under a load of 0.45 MPa, such as P.
It is composed of a fluororesin such as TFE (Poly Tetra Fluoro Ethylene) or a PEEK (Poly Ether Ether Ketone) resin material.

[0016]

Since the semiconductor wafer cleaning cassette according to the present invention is constructed as described above, the wafer is provided with a plurality of support pins projecting from the inner wall surface of the main body of the cleaning cassette for each wafer. By bringing the peripheral surface of the end of the wafer into contact with the plate surface of the wafer, each wafer is firmly supported without inclining.

Therefore, the line contact between the wafer and the support pin is almost close to a point, the contact area between the two is greatly reduced as compared with the conventional cleaning cassette, and the wafer plate surface is prevented from being scratched or soiled. .

In addition to the support pins, the wafer is loosely fitted in the grooves of the guide member provided between the support pins, and the wafer is sandwiched between a pair of grooves located on the left and right of the guide member. As a result, since the wafer is supported in a state where the position in the depth direction (vertical direction) is regulated, the wafer can be reliably positioned in the cleaning cassette.
A large number of wafers can be firmly placed side by side in the cleaning cassette to perform the cleaning operation. Therefore, the distance between the left groove and the right groove of the guide member must be set to be at least narrower than the wafer diameter.

In this case, since the guide member has the minimum necessary width and the depth of the groove so that the groove can be positioned, the contact area with the wafer is hardly increased by installing the guide member. is there.

Further, according to the invention of claim 4, the guide member and the support pin of the cleaning cassette are 0.45MP.
a polymer material having a heat distortion temperature of 100 ° C. or higher under the load of a,
For example, by using a fluororesin or PEEK resin material such as PTFE, under normal cleaning temperature conditions, there is almost no thermal deformation of the cleaning cassette including the support pins, the guide member, and the cassette body, and the wafer can be always treated with a uniform force. It is possible to carry and carry out a cleaning operation.

[0021]

Embodiments of the present invention will be described in detail below with reference to FIGS. However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention thereto, but merely illustrative examples. Nothing more.

1 to 4 are structural views of a cleaning cassette used in a semiconductor wafer cleaning process according to the first embodiment of the present invention. FIG. 1 is a front view thereof, and FIG. 2 is a line II- of FIG. II line enlarged sectional view, FIG. 3 is a view taken in the direction of arrow III in FIG. 1, and FIG.
FIG. 4 is an enlarged sectional view taken along line IV.

1 to 4, 1 is a cleaning cassette, and 2 is a cleaning cassette.
Reference numeral 1 is a main body of the cleaning cassette, and 2 is a wafer to be cleaned, which is housed in the main body 21. The main body 21 of the cleaning cassette is composed of a box-shaped body having an opening 26 for inserting and removing the wafer 2 on the upper surface thereof, so that the cleaning wafers 2 are juxtaposed in the longitudinal direction (see FIG. 3). It has become.

Reference numerals 23a and 23b are support pins projecting from the inner surfaces of both side walls of the main body 21 of the cleaning cassette, and 24 is a guide member projecting between the support pins 23a to 23b.

The support pins 23a-23b and the guide member 24 are provided so as to project from the inner surfaces of both side walls of the main body 21 toward the center. In this embodiment, one support pin is provided on each side of the wafer 2. Two (23a, 23b) and one guide member 24 are provided on each of the left and right sides. The support pins 23a-23b and the guide member 24 are shown in FIG.
As is clear from the above, a plurality of rows are provided in the longitudinal direction of the main body 21, and each row can support one wafer 2.

The ends of the wafers 2 are loosely fitted in the grooves 24a of the guide members 24 in each row, and the wafers are sandwiched between the inner portions 24b, 24b of the pair of grooves located on the left and right of the guide member 24. By doing so, the position is regulated in the depth direction (vertical direction). Therefore, the distance P between the left and right groove portions 24b, 24b of the guide member is set to be narrower than the wafer diameter. (See Fig. 4)

Further, the support pins 23a-23b of each row are
The outer peripheral surface of the small-diameter tip portion is in contact with the plate surface 2a of the wafer 2. This contact mode is, as shown in FIG.
The support pins 23a and one plate surface 2a of the wafer 2 are brought into contact with each other, while the other support pins 23b are brought into contact with the plate surface 2a 'on the opposite side of the wafer 2 to prevent the wafer 2 from collapsing. are doing.

The groove 24a of the guide member 24 is used for positioning the wafer 2 and therefore has a width b.
(See FIG. 2) as much as possible, and as shown in FIG. 4, the mirror surface of the wafer 2 is formed by forming the groove surface on the mirror-finished plate surface 2a side by c shorter than the opposite side. The contact area between the plate surface 2a on the finishing side and the guide member 24 is reduced.

Further, the relative positions of the support pins 23a-23b and the guide member 24 are set such that the pitch of the wafers 2 is made uniform, the wafers 2 are held parallel to each other, contact is avoided when the wafers are tilted in the opposite direction, and further the guides are provided. It is set in consideration of the draining effect of the wafer 2 in the groove 24a of the member 24.

That is, in this embodiment, as shown in FIG. 3, when the wafer 2 is stored in the cleaning cassette 1, the groove 24a of the guide member 24 is inclined so as to be inclined about θ = 3 ° with respect to the vertical line. The direction and the installation positions of the support pins 23a to 23b are determined to meet the above requirements.

Further, the cassette body 21 and the support pins 2
The cleaning cassette including 3a to 23b and the guide member 24 is
At least the guide member and the support pin are 0.45M
It is made of a polymer material having a heat distortion temperature of 100 ° C. or higher under a load of Pa, for example, a fluororesin such as PTFE or a PEEK resin material.

Reference numeral 22 is a holding flange formed on the upper portion of the main body 21, and as shown in FIG. 1, the flange 22 is engaged with an arm 31 of a cleaning robot to clean the cleaning cassette 1 by the robot. It can be immersed in or taken out from a tank (not shown). Reference numeral 25 is a reinforcing rim provided between the left and right side walls of the main body.

When cleaning the wafer using the cleaning cassette 1 constructed as described above, the wafer 2
Is loosely fitted into the groove 24a of the guide member 24 at two end edges thereof, and the wafer end surface abuts on the inner portions 24b, 24b of the pair of grooves located on the left and right of the guide member 24, and the position in the depth direction. While being clamped while being regulated, one of the plate surfaces 2a is brought into contact with the outer peripheral surface of the small-diameter tip portion of the support pin 23a, and the other (opposite surface) 2a 'of the plate surface is formed with the small diameter of the support pin 23b. Both ends are supported by being brought into contact with the outer circumference of the tip portion.

Therefore, the wafer 2 and the support pins 23a ...
23b is a line contact close to a point, and the groove 24a of the guide member 24 is wide and deep enough to simply position the wafer 2. Therefore, the supporting surface of the wafer 2 and the cleaning cassette 1 is supported. The contact area with is much smaller than the conventional one. This prevents the plate surface of the wafer 2 from being scratched or soiled.

Further, since the wafer 2 is supported by combining a plurality of support pins 23a-23b and the guide member 24 per one of the wafers 2, the wafer 2 falls in the cleaning cassette 1 and is supported by the supporting portion. It is firmly supported without causing problems such as falling off.

Further, as described above, the cleaning cassette 1 has P
It is made of a fluororesin or PEEK resin material such as TFE. Table 1 shows a comparison of general physical properties between the PTFE resin material and the PEEK resin material and the PFA resin material used in the conventional cleaning cassette.

[0037]

[Table 1]

As is clear from Table 1, for example, PEE
The K resin material has much higher tensile strength and flexural elasticity than the PFA resin material, but the heat deformation temperature under load of 0.45 MPa is 128 ° C for PTFE and 152 for PEEK.
C. and 1.7 to 2 times higher than PFA (75.degree. C.). Therefore, even if the cleaning cassette 1 is used at a temperature (about 80 ° C.), the cleaning cassette 1 is hardly deformed by heat, and each wafer 2 has the support pins 23a to 23 of the cleaning cassette 1 even at high temperatures.
b and the guide member 24 are reliably supported by a uniform force.

FIGS. 5 to 7 show another embodiment of the present invention. In this embodiment, unlike the above-described embodiment, each wafer 2 has three support pins (23a, 23b, 2) on the left and right sides.
3c), one left and right guide member 24 is provided.
As shown in FIG. 7, the support pins 23a to 23c and the guide member 24 are provided in a plurality of rows in the longitudinal direction of the main body 21 of the cleaning cassette, and one wafer 2 is provided in each row.
Can be supported.

The groove 24a of the guide member 24 in each row and the support pins 23a and 23b in each row are the same as in the above embodiment, as shown in FIG.
It is set at an inclination angle of about 3 ° so as to make the pitch of the wafers 2 uniform and hold the wafers 2 in parallel when stored in the cleaning cassette 1. That is, the inner portions 24 b, 24 of the pair of grooves located on the left and right of the guide member 24.
By sandwiching the wafer between b, the position in the depth direction (vertical direction) is regulated, and the lower support pin 23a located on the mirror surface side and the upper support pin 23 located on the opposite mirror surface side.
With b, the angle regulation of the inclination angle of θ = 3 ° is performed,
As a result, only the end surface of the groove 24a is in contact with the groove 24a, and the peripheral surfaces of the support pin 23a and the support pin 23b are substantially in point contact with each other on the mirror surface and the anti-mirror surface at the normal tilt position, and more specifically, substantially. It will come into contact with a line contact near the point.

In this embodiment, in particular, the third support pin 23c is provided so as to avoid the collision with the adjacent wafer when the wafer is tilted backward. That is, the third support pin 23c is disposed slightly below the upper support pin 23b on the mirror surface side, and the support pin 23c contacts the mirror surface when the wafer is housed in the regular position at an inclination angle of 3 °. Without
It is made to project at a slightly separated position. As a result, the third support pin 23c does not interfere with the normal storage of the wafer, and it is possible to avoid the collision with the adjacent wafer when the wafer is tilted.

[0042]

According to the present invention, a semiconductor wafer housed in a cleaning cassette is provided with a wafer surface on the peripheral surface of the end portions of a plurality of support pins protruding from the inner wall surface of the cassette body. The contact area between the wafer and the support pin, which is the support member on the cleaning cassette side, is significantly smaller than the conventional one because it is configured to abut and support the wafer cassette surface. Can be prevented.

According to the second aspect of the invention, since the wafer is loosely fitted and supported in the groove of the guide member in addition to the support pin, the wafer can be reliably positioned in the cleaning cassette. A large number of wafers can be firmly placed side by side in the cleaning cassette to perform the cleaning operation.

In this case, since the guide member has the minimum necessary width and the depth of the groove is sufficient for positioning, the increase of the contact area with the wafer due to the installation of the guide member is extremely small. Is.

Further, according to the invention of claim 3, since the wafer is supported in a state in which the position in the depth direction (vertical direction) is regulated, the wafer can be reliably positioned in the cleaning cassette, and a large number of wafers can be positioned. The cleaning operation can be performed by firmly arranging the wafers side by side in the cleaning cassette.

Further, according to the invention of claim 4, since a resin material having a higher heat deformation temperature than that of the conventional PFA resin material is used, the support pin, the guide member, and the cassette body can be used under normal washing temperature conditions. There is almost no thermal deformation of the cleaning cassette including the wafer, and the cleaning operation can be performed by always supporting the wafer with a uniform force.

As a result, it is possible to almost completely prevent defective products due to scratches and stains on the wafer due to the contact area of the cleaning cassette and thermal deformation when cleaning the semiconductor wafer, and to improve the quality of the wafer and the product yield. .

[Brief description of drawings]

FIG. 1 is a front view of a cleaning cassette used in a semiconductor wafer cleaning process according to a first embodiment of the present invention.

2 is an enlarged sectional view taken along line II-II of FIG.

FIG. 3 is a view on arrow III in FIG.

FIG. 4 is an enlarged sectional view taken along line IV-IV of FIG.

FIG. 5 is a front view of a cleaning cassette used in a semiconductor wafer cleaning process according to another embodiment of the present invention.

6 is an enlarged sectional view taken along line II-II of FIG.

FIG. 7 is a view on arrow III in FIG.

FIG. 8 is a front view of a conventional semiconductor wafer cleaning cassette.

9 is a sectional view taken along line VI-VI of FIG.

[Explanation of symbols]

 1 Cleaning Cassette 2 Semiconductor Wafer 21 Cleaning Cassette Body 23a, 23b, 23c Support Pin 24 Guide Member 24a Guide Member Groove

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hideki Munakata, Inventor Hideki Munakata Odaira, Odaira, Saigo-mura, Nishishirakawa-gun, Fukushima 150 Inside the Shirakawa Plant, Shin-Etsu Semiconductor Co., Ltd. (72) Tomasa Yamada 1-25-15 Edobori, Nishi-ku, Osaka Japan VALQUA INDUSTRY CO., LTD. Osaka Branch (72) Inventor Yasuo Yabe 6-13-3 Ginza, Chuo-ku, Tokyo Japan VALQUA INDUSTRY CO., LTD. Tokyo Branch (72) Inventor Makoto Ikeda Ichibancho, Aoba-ku, Sendai-shi, Miyagi 1-12-16 Dainichi Trading Co., Ltd. Sendai Branch Office

Claims (4)

[Claims] 1. A cleaning cassette used in a semiconductor wafer cleaning step, wherein a plurality of support pins are arranged in a plurality of rows in the longitudinal direction of the cassette from the inner wall surface of the main body of the cleaning cassette along the circumferential direction of the semiconductor wafer. A cleaning cassette for a semiconductor wafer, wherein the cleaning cassette for a semiconductor wafer is configured to project and to support an end peripheral surface of the support pin against the plate surface of the wafer to support the wafer. 2. A cleaning cassette used in the step of cleaning a semiconductor wafer, wherein a plurality of support pins are arranged in a plurality of rows in the longitudinal direction of the cassette from the inner wall surface of the main body of the cleaning cassette along the circumferential direction of the semiconductor wafer. The support pin is projected, and the peripheral surface of the end of the support pin is brought into contact with the plate surface of the wafer, and the wafer is loosely fitted in the groove of the guide member provided between the support pins. A cleaning cassette for a semiconductor wafer, which is configured to support the wafer by a guide member. 3. A pair of guide members having a groove portion between the support pins are arranged on both sides in the lateral direction of the cassette,
Both end surfaces of the wafer contact the inner end of the groove of the guide member,
The cleaning cassette according to claim 2, wherein the cleaning cassette is configured to be supported in a state in which the position of the wafer is regulated in the depth direction. 4. A heat distortion temperature of 100 ° C. under a load of 0.45 MPa at least in the guide member and the support pin.
The cleaning cassette according to claim 1, which is made of the above polymer material.