Data processing: generic control systems or specific application – Specific application – apparatus or process – Article handling
Reexamination Certificate
1999-12-29
2001-11-13
Ellis, Christopher P. (Department: 3651)
Data processing: generic control systems or specific application
Specific application, apparatus or process
Article handling
C324S765010
Reexamination Certificate
active
06317647
ABSTRACT:
TECHNICAL FIELD
The present invention relates to an aligner.
More specifically, the invention relates to an aligner applicable to the case of collective inspection of a large number of semiconductor devices (hereinafter referred to as “IC chips”) formed on a semiconductor wafer (hereinafter referred to as “wafer”).
An aligner is a technique for forming a test shell including a contactor, wafer, and wafer holder (hereinafter referred to as “wafer chuck”) that are united by means of a vacuum sucking force. The contactor is electrical contact means that comprises contact terminals capable of collectively electrically touching a plurality of electrodes of a plurality of IC chips on the wafer and external terminals connected individually to the contact terminals.
BACKGROUND ART
In a semiconductor inspection process, a large number of IC chips formed on a wafer are checked for electrical properties, and those chips which have no defects in electrical properties are screened. The screened non-defective chips are packaged by means of a synthetic resin or ceramic material in an assembly process. In a reliability test, moreover, the packaged products are subjected to temperature stress and electrical stress to detect potential defects and the like in the chips, whereby defective ones can be removed.
With the development of smaller-sized, higher-function electrical products, on the other hand, chips have been reduced in size and enhanced in integration. Recently, various mounting techniques have been developed further to miniaturize semiconductor products. In particular, there have been developed techniques for mounting unpackaged chips or so-called bare chips. The bare chips require quality assurance when they are brought to market. In order to obtain guaranteed bare chips, the individual IC chips must be checked for reliability.
In inspecting bare chips by means of a conventional reliability tester, it is necessary to solve various problems including electrical connections between the bare chips and sockets. Besides, handling the small bare chips is very difficult and possibly entails an increase in inspection cost.
Accordingly, techniques for reliability tests have been proposed in Jpn. Pat. Appln. KOKAI Publications Nos. 7-231019, 8-5666 and 8-340030, for example. According to these techniques, a plurality of wafers can be collectively subjected entire to the tests with IC chips formed thereon.
Conventionally, however, a contactor is opposed to each wafer, contact terminals of the contactor are visually aligned with a plurality of electrodes of a plurality of IC chips formed on the wafer (hereinafter referred to as “alignment”), and the terminals and the electrodes are collectively brought into contact with one another. In carrying out this operation, an operator's operation for alignment between a reference contact terminal and its corresponding electrode pad takes a lot of time. Thus, the operating efficiency is poor, the operator is heavily burdened, and a stable contact state cannot be obtained with ease due to personal errors in alignment accuracy.
In Jpn. Pat. Appln. No. 10-54423, therefore, the applicant hereof proposed a technique (aligner) for forming a unit (hereinafter referred to as “test shell”) by translating a stage, carrying thereon a wafer chuck holding a wafer, in X, Y and &thgr; directions with respect to a contactor, thereby aligning the wafer and the contactor, moving the stage in a Z direction thereafter, and collectively bringing the three elements, i.e., the contactor, wafer, and wafer holder, into contact with one another by means of a vacuum sucking force that is formed by a vacuum suction mechanism attached to the wafer holder.
This aligner can be also used for the case where the test shell is disassembled or reduced to the aforesaid three elements after testing. During this disassembly, the test shell is transferred from a test chamber to a predetermined position in an alignment chamber. This predetermined position is the same position where the test shell is formed. In disassembling the test shell to the aforesaid three elements, therefore, it is necessary to move the stage accurately to the position where the test shell is formed. By doing this, the test shell and the stage are aligned with each other, whereupon an air charging-exhaust device (valve control mechanism) that is mounted on the stage is connected to a valve mechanism of the vacuum suction mechanism of the wafer chuck. As the valve control mechanism operates the valve mechanism of the wafer chuck, the vacuum sucking force of the wafer chuck is canceled, whereupon the shell is allowed to be disassembled or reduced to the three elements.
Actually, however, the stage cannot always be located in a predetermined position with respect to the test shell that is carried into the alignment chamber after testing. In this case, it is hard accurately to align a valve control mechanism attached to a main chuck with a valve mechanism of the tested shell on the aligner.
DISCLOSURE OF THE INVENTION
An object of the present invention is to solve the problems described above.
Another object of the present invention is to provide an aligner in which a test shell can be securely placed on a stage by securely locating the stage in the position in which the shell is integrated, without regard to the position of a wafer on a wafer holder, when the shell, which is obtained by uniting a contactor, the wafer, and the wafer holder, is disassembled.
According to a first aspect of the present invention, there is provided an aligner for forming and disassembling a test shell, comprising: a contactor including a plurality of contact terminals electrically in contact with a plurality of electrodes of a plurality of semiconductor devices formed on a semiconductor wafer; a wafer holder provided with a vacuum suction mechanism including a valve mechanism and capable of holding the contactor and the semiconductor wafer by means of a vacuum sucking force formed by the vacuum suction mechanism, thereby forming an integral test shell; a stage for supporting the wafer holder for movement in X, Y, Z and &thgr; directions; a first control device for effecting control for moving the stage in the X, Y and &thgr; directions so that the plurality of contact terminals and the plurality of predetermined electrodes are aligned with one another and controls for moving the stage in the Z direction so that the contact terminals and the electrodes are in contact with one another; a valve control mechanism mounted on the stage and used to connect and disconnect the valve mechanism of the wafer holder to and from an exhaust device, the valve control mechanism serving to connect the vacuum suction mechanism of the wafer holder to the exhaust device, cause the vacuum suction mechanism to form the vacuum sucking force, and cancel the vacuum sucking force of the vacuum suction mechanism of the wafer holder, thereby reducing the test shell to the wafer holder, the semiconductor wafer, and the contactor; a storage unit for storing position information on the position in which the stage is moved in the X, Y and &thgr; directions to align the plurality of contact terminals and the plurality of electrodes with one another; and a second control device adapted to move the stage to the position in accordance with the position information stored in the storage unit and place the test shell on the stage in the position, thereby canceling the vacuum sucking force, as the vacuum sucking force is canceled by means of the valve mechanism to disassemble the test shell.
Preferably, in this aligner, the test shell is a shell for one test, out of a reliability test and an electrical property test.
Preferably, this aligner comprises a reader for reading an identification code provided outside the wafer holder and/or the contactor, and in this aligner, the storage unit also stores the identification code, and the second control device moves the stage to the position in accordance with the identification code and the position information.
Preferably, in this aligne
Akaike Yutaka
Kono Isao
Sano Satoshi
Ellis Christopher P.
Morrison & Foerster / LLP
Tokyo Electron Limited
Tran Khoi H.
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