JP2010157584A - Method of transporting silicon wafer for analysis - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To inexpensively and easily transport several types of silicon wafers different in level of contamination concentration, in relation to a method of transporting a silicon wafer for analysis. <P>SOLUTION: This method of transporting a silicon wafer for analyzing contamination concentration on a surface of the silicon wafer includes: a bonding process S10 of bonding two silicon wafers in the same lot to each other by facing front surfaces thereof to each other while keeping a state intended to be analyzed; a transport process S20 of transporting the two silicon wafers in a state where they are bonded to each other by housing them in a wafer case after the bonding process S10; and a separation process S30 of separating the two silicon wafers in the state where they are bonded to each other into original single states after the transport process S20, and respectively introducing the separated silicon wafers into an analysis device. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a method for transporting a silicon wafer to analyze the contamination concentration.

Conventionally, in order to analyze the contamination concentration on the surface of a silicon wafer, the silicon wafer is stored in a dedicated wafer case and transported to an analyzer.
As a dedicated wafer case, for example, aluminum that can store a plurality of wafers as described in Patent Document 1 at a time so that the silicon wafer is contaminated from the surrounding environment during transportation and does not affect the analysis value. A box-shaped case made of metal is used.
JP 2000-3957 A

However, the aluminum box-type case described in Patent Document 1 is expensive, and silicon wafers having different levels of contamination cannot be put in the same case. In this case, it is necessary to prepare a large number of cases. there were.
The present invention has been devised in view of such problems, and provides a method of transporting an analytical silicon wafer that can transport several types of silicon wafers having different levels of contamination concentration at low cost and easily. The purpose is to do.

  To achieve the above object, the method for transporting an analytical silicon wafer according to the present invention is the same as the method for transporting a silicon wafer for analyzing the contamination concentration on the surface of the silicon wafer. A bonding step of bonding two silicon wafers with their surfaces facing each other while maintaining the state to be analyzed, and after the bonding step, A transporting process for storing and transporting two silicon wafers in a wafer case, and after the transporting process, the two bonded silicon wafers are peeled back to the original one state, And a peeling step of introducing each of the peeled silicon wafers into an analyzer.

  The above analysis is preferably an analysis of at least one of organic substance concentration, ion concentration and metal concentration.

  According to the method for transporting an analysis silicon wafer of the present invention, the transport for contamination concentration analysis can be performed by simply bonding the surfaces of two silicon wafers, which are estimated to have the same contamination concentration, to face each other. At this time, contamination from the surrounding environment can be prevented, and a general case can be used without using an expensive dedicated case. Also, several types of silicon wafers having different levels of contamination concentration can be stored in the same case, and the number of cases can be reduced. That is, several types of silicon wafers having different levels of contamination concentration can be transported at a low cost.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a flowchart showing a method for transporting an analytical silicon wafer according to an embodiment of the present invention, FIG. 2 is a schematic perspective view of a bonding apparatus used as an example in a bonding step of the transport method, and FIG. It is a typical top view of the peeling apparatus used as an example at the peeling process of a conveyance method.

[Overview]
The method for transporting a silicon wafer for analysis according to the present invention is for analyzing the contamination concentration on the surface of a silicon wafer. As shown in FIG. 1, two silicon wafers estimated to have the same contamination concentration are used. While maintaining the state to be analyzed, the bonding step S10 for bonding the surfaces (surfaces) to be analyzed facing each other, and the bonded silicon wafer after the bonding step S10 are generally used. After carrying step S20 for carrying in a carrying wafer case and carrying, and after carrying step S20, the bonded silicon wafer is peeled back to one original state, and each of the peeled silicon wafers is analyzed. And a peeling step S30 to be introduced into the apparatus. The separation step S30 is followed by an analysis step S40, where the contamination concentration on the surface of the silicon wafer is analyzed by an analyzer.

If the silicon wafer is in the same lot, the contamination concentration is estimated to be the same level.
Moreover, it is preferable that said analysis is an analysis of at least any one of organic substance concentration, ion concentration, and metal concentration.
Each of the above steps will be described in detail below.

[1. Bonding process]
The bonding in the bonding step S10 is performed by an automatic (fully automatic or semi-automatic) bonding apparatus or manually, and the method is not particularly limited.
In other words, two silicon wafers may be stacked on the bonding table with the surfaces facing each other and bonded by applying a load, or the bonding table is housed in a chamber and bonded together under reduced pressure. May be performed.

  Further, as shown in FIG. 2, a pedestal 1, a pair of support columns 2 erected on the pedestal 1, a wafer support table 4 sandwiched between the pair of support columns 2 via a rotating shaft 3, and a wafer support table A known bonding apparatus 10 having a holding member 5 attached to the lower part of 4 is prepared, and the first silicon is used by using vacuum tweezers or the like with the wafer support 4 set at an angle close to the vertical. The wafer may be supported on the holding member 5, and then the second silicon wafer may be brought into gentle contact with the first silicon wafer, and finally the wafer support 4 may be placed in a horizontal state for bonding. Note that the bonding apparatus shown in FIG. 2 is described in Japanese Patent Application Laid-Open No. 2006-303087.

  Note that even if voids (voids formed at the bonding interface) occur in the inner part (inner peripheral part) of the silicon wafer in the circumferential direction, the analysis value is not affected, so there is no need to consider the yield. However, regarding the voids in the outer peripheral portion, since there is a possibility that contamination enters from the surrounding environment, it is preferable that no voids are generated.

[2. Transport process]
The case used in the transporting process S20 may be a known general transporting case used in a clean room, and is not particularly limited.
That is, for example, as described in JP-A-7-307379, a case body and a large number of silicon wafers (here, a number of bonded silicon wafers) housed in the case body A transport case including a cassette that is supported in parallel and a lid that closes the case main body in a state where the cassette is housed in the case main body may be used, or another appropriate transport case may be used.

[3. Peeling process]
For the peeling operation in the peeling step S30, it is preferable to use a dedicated peeling device, but it may be peeled off with a sandwich type tweezers made of resin or metal. However, when using tweezers, care must be taken not to contact the bonding interface. Therefore, it is preferable to use a dedicated peeling device.

As a dedicated peeling device, for example, a peeling device 20 that simultaneously peels a plurality of wafers as shown in FIG. 3 may be used, but a simple peeling device that peels one by one may be used.
Here, the peeling device 20 shown in FIG. 3 will be briefly described. The peeling device 20 is a known device described in Japanese Patent No. 3656254, and is a transfer robot (transfer means) installed in the center. 11), a cassette station 12 provided with a cassette 12a for storing two bonded silicon wafers (bonded wafers), and a cassette station provided with a cassette 13a for storing a lower wafer after peeling. 13, a cassette station 14 provided with a cassette 14 a for storing the upper wafer after peeling, and a peeling station 15.

  The cassette stations 12 to 14 and the peeling station 15 are arranged side by side in the circumferential direction on the same circumference around the transfer robot 11, and the peeling station 15 holds the bonded wafer horizontally. Move the movable peeling jig 15c, the peeling table 15d having the suction table (holding body) 15a, the fixed peeling jig 15b and the movable peeling jig 15c in which the insertion portion to be inserted between the bonded wafers is formed. And an air cylinder (driving means) 15e.

Specific examples will be described below.
[Example 1]
After preparing two silicon wafers in the same lot estimated to have the same organic substance concentration (that is, contamination concentration), bonding was performed using a dedicated bonding jig (bonding step S10). Next, the silicon wafer bonded to a general transport wafer case was stored and transported to the place of the analyzer (transport process S20). Finally, the silicon wafer bonded with the aluminum tweezers is peeled off to the original one state, each silicon wafer is introduced into the analyzer (peeling step S30), and the organic matter is analyzed (analyzing step) S40).

  As a result, as shown in the following table, it was confirmed that the contamination concentration was the same as when the conventional method was used (contained and transported in a dedicated aluminum case).

[Example 2]
After preparing 5 different levels of organic matter, each with 2 sheets, bonding is performed in the same manner as in Example 1, and the bonded wafers at the 5 levels are stored in the same general transport wafer case. did. Thereafter, analysis was performed in the same manner as in Example 1.
As shown in the table below, the results are the same as when the conventional method is used (when stored in a dedicated aluminum case for each level) and by using the method of the present invention. It was confirmed that the analysis value was not affected by storing different levels of concentration together.

[effect]
As described above, according to the method for transporting an analytical silicon wafer of the present invention, an easy procedure is performed in which the surfaces of two silicon wafers, which are estimated to have the same contamination concentration, are bonded face to face. Thus, during transportation for analyzing the concentration of contamination, contamination from the surrounding environment can be prevented, and a general case can be used without using an expensive dedicated case. Further, several types of silicon wafers having different levels of contamination concentration can be stored in the same case, and the number of cases can be reduced. That is, several types of silicon wafers having different levels of contamination concentration can be transported at low cost and easily.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

It is a flowchart which shows the conveyance method of the silicon wafer for analysis which concerns on one Embodiment of this invention. It is a typical perspective view of the bonding apparatus used as an example by the bonding process of the conveyance method of the analytical silicon wafer which concerns on one Embodiment of this invention. It is a typical top view of the peeling apparatus used as an example in the peeling process of the conveyance method of the silicon wafer for analysis concerning one embodiment of the present invention.

Explanation of symbols

10 Bonding device 20 Peeling device

Claims (2)

In the silicon wafer transport method for analyzing the contamination concentration of the silicon wafer surface,
A bonding step of bonding two silicon wafers in the same lot with the surfaces facing each other while maintaining the state to be analyzed;
After the bonding step, a transporting step of storing and transporting the two silicon wafers in the above-mentioned bonded state in a wafer case,
After the transporting step, there is provided a peeling step of peeling the two bonded silicon wafers into the original one state and introducing each of the peeled silicon wafers into the analyzer. A method for transporting a silicon wafer for analysis, characterized in that 2. The method for transporting an analytical silicon wafer according to claim 1, wherein the analysis is an analysis of at least one of an organic substance concentration, an ion concentration, and a metal concentration.

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