JPH10261700A - Carrier for semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a carrier for semiconductor wafer in which a semiconductor wafer contained in the carrier is prevented from being contaminated with foreign matters during carriage or being warped by attracting the semiconductor wafer fixedly to a support, i.e., an electrostatic chuck. SOLUTION: A carrier containing a plurality of semiconductor wafers 2 is held at the handle thereof and transferred while being mounted on a moving truck. When it is connected not with the DC power supply of the moving truck but with an independent DC power supply 4, the carrier can be used as a preservation case as it is. More specifically, an electrostatic chuck 3 provided on the carrier supports the semiconductor wafer 2 horizontally at the opposite ends on both sides and brings the gravitationally warped semiconductor wafer 2 into tight contact with the supporting face of the electrostatic chuck 3 through no gap thus lessening the warp. Furthermore, no foreign matter, e.g. abrasion powder, is generated through fixing of a movable part because the support, i.e., the electrostatic chuck 3 itself, secures the semiconductor wafer 2 which is thereby protected against contamination with foreign matters.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier for storing or transporting a semiconductor wafer, and more particularly to a structure for fixing a semiconductor wafer to a carrier.

2. Description of the Related Art In a semiconductor device manufacturing process, it is required to prevent a semiconductor wafer from being warped or moved when the semiconductor wafer is housed and fixed in a carrier.

[0003]

2. Description of the Related Art In a conventional semiconductor wafer carrier, there are problems such as wafer pitching and cracking due to abnormal vibration during transfer and jumping out of the carrier.
No. 82, there is a structure in which the outer periphery of a stored semiconductor wafer is pressed and fixed by a pressing member urged by a coil spring, and the fixing member is released by moving the pressing member by a release mechanism to release the semiconductor wafer. I'm taking it out.

Japanese Patent Laid-Open Publication No. Hei 3-201459 discloses another solution without a movable part. The structure is such that a hollow cushion is provided near the outer periphery of a stored semiconductor wafer to increase the internal pressure of the hollow cushion. The outer periphery of the semiconductor wafer is held by expanding the semiconductor wafer.

[0005]

However, according to the above-mentioned structure, the former structure has mechanical moving parts such as a pressing member and a coil spring. There is a problem that foreign matter adheres to and contaminates the semiconductor wafer, or the semiconductor wafer is warped because the outer periphery of the semiconductor wafer is pressed in the diameter direction. Further, in the latter structure, although the hollow cushion is used, there is also a problem that the semiconductor wafer is pressed similarly, so that the semiconductor wafer is also warped.

In view of the above problems, an object of the present invention is to provide a semiconductor wafer carrier in which a semiconductor wafer accommodated in the carrier is not contaminated by foreign matter during transportation and the semiconductor wafer does not warp.

[0007]

In order to achieve the above-mentioned object, a semiconductor wafer carrier according to the present invention has a structure as shown in FIG.
As shown in the principle diagrams of (a) and (b), at least one pair of electrostatic chucks 3, that is, 3 a and 3 b, which are fixed to the carrier main body 1 and adsorb and support the peripheral edge of the semiconductor wafer 2, And a DC power supply 4 for simultaneously applying a DC voltage to each of the electrostatic chucks 3.

In the electrostatic chuck, when a predetermined DC voltage is applied to positive and negative electrodes provided on the surface of a ceramic substrate or the like, a negative charge and a positive charge are generated in a semiconductor wafer to be attracted, respectively. The substrate and the semiconductor wafer are electrostatically attracted. When the peripheral edge of the semiconductor wafer is horizontally supported on at least two surfaces by such an electrostatic chuck, when the electrostatic chuck 3 shown in FIG. Edges 3 of the support surfaces (suction surfaces) of the electrostatic chucks 3a and 3b
It warps with a-1 and 3b-1 as fulcrums. This warpage causes a gap 3a- between the chucking surfaces of the electrostatic chucks 3a and 3b.
Yields 2,3b-2.

On the other hand, as shown in FIG.
When the switch 5 is turned on the electrostatic chucks 3a and 3b supporting the semiconductor wafer 2 and a DC voltage is applied thereto and the semiconductor wafer 2 is attracted, the semiconductor wafer 2 adheres to the respective attracting surfaces of the electrostatic chucks 3a and 3b without any gap. A moment around the fulcrum is generated in the direction of the arrow by the electrostatic attraction force, so that warpage caused by its own weight can be reduced. Further, since no mechanical moving parts are used for the fixing means of the semiconductor wafer 2, no foreign matter is generated and the semiconductor wafer 2 is not contaminated.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The gist of the present invention will be described below in detail with reference to the embodiments shown in the drawings. FIG. 2 is a front view and FIG. 3 is a perspective plan view of FIG. FIG. 3 omits illustration of the electrical connection portion.

As shown in FIGS. 2 and 3, a semiconductor wafer carrier according to the present invention comprises a box-shaped carrier body 1 having an opening 2a for inserting and removing a semiconductor wafer 2, and a carrier body 1 having an upper surface. A pair of left and right electrostatic chucks 3, that is, a pair of left and right electrostatic chucks 3 a, 3 a and 3 b (shown by oblique lines in FIG. 2) fixed to the opposing side walls 1 a-3 of the carrier body 1. DC power supply 4 for applying a DC voltage to electric chucks 3a and 3b (for example, provided on a mobile carriage (not shown) for carrying and carrying a carrier), and terminal board 1b provided on the side surface of the carrier body to turn on / off the supplied power. And a suction force adjusting means 6 comprising a variable resistor for variably adjusting the applied DC voltage.

The wafer supporting surface of the electrostatic chuck 3 is finished flat, and two electrodes 31a, 3a are provided inside the ceramic.
1b is embedded. The patterns of the electrodes 31a and 31b have various shapes such as concentric circles and spirals. The electrostatic chucks 3 of each stage support the peripheral portion of the semiconductor wafer 2 on two pairs horizontally on a support surface. The electrodes 31a and 31b of each stage of the electrostatic chuck 3 are connected in parallel with the corresponding switch 5.

The DC power supply 4 applies approximately +1.5 KV to the electrode 31a via the switch 5 during transportation or storage,
To about 1.5 KV. The switch 5 is provided corresponding to the electrostatic chuck 3 of each stage, and turns on / off the power supply of the stage when the semiconductor wafer 2 is placed on the electrostatic chuck 3 or when the semiconductor wafer 2 is taken out. It is desirable to turn on / off for each stage.

An attraction force adjusting means (variable resistor) 6 variably adjusts a DC voltage value applied to the electrostatic chuck to increase or decrease the electrostatic attraction force of the electrostatic chuck 3. Although two variable resistors 6 are connected in the illustrated example, it is desirable to provide two variable resistors 6 for each stage so that the electrostatic attraction force can be adjusted for each stage.

Next, a case where a semiconductor wafer is carried (or stored) on the carrier by placing the semiconductor wafer on an electrostatic chuck will be described. First, a plurality of semiconductor wafers 2 are placed horizontally on a pair of left and right electrostatic chucks 3. At this time, since the peripheral portion of the semiconductor wafer 2 is supported on the left and right two surfaces, the edges 3a-1 and 3b-1 of the support surfaces (suction surfaces) of the pair of electrostatic chucks 3a and 3b are owed to their own weight. It is warped as a fulcrum as shown by a two-dot chain line in FIG. This is exemplified by the uppermost semiconductor wafer 2. Especially, diameter 1
A large-diameter semiconductor wafer of 2 inches or more tends to be warped. In this state, gaps 3a-2 and 3b-2 are formed between the warp and the respective support surfaces (suction surfaces) of the pair of electrostatic chucks 3a and 3b.

Therefore, with the switch 5 turned on, a DC voltage is simultaneously applied to the pair of left and right electrostatic chucks 3a and 3b (+ approximately 1.5 KV to the electrode 31a and approximately −KV to the electrode 31b).
When the semiconductor wafer 2 is placed, the electrostatic chucks 3a and 3b electrostatically attract a portion overlapping the support surface.

A moment about the fulcrum is generated by the electrostatic chucking force, and the semiconductor wafer 2 is held on a pair of electrostatic chucks 3.
a) and 3b are closely adhered to the support surfaces without any gap, thereby reducing the warpage caused by its own weight. When the semiconductor wafer 2 is taken out, the switch 5 is cut off.

The carrier accommodating a plurality of semiconductor wafers 2 is carried on a movable carriage (not shown) with the handle 1a-1. A DC power supply is mounted on the mobile trolley, and a power receiving connector 1b provided on a terminal plate 1b of the carrier body 1 is provided.
1 through the power supply.

Alternatively, the carrier can be used as it is as a storage container if it is connected to a separately provided DC power source instead of the DC power source of the mobile trolley. As described above, the electrostatic chuck provided on the carrier supports the semiconductor wafer horizontally at both ends, and at the same time, electrostatically chucks the supported and warped semiconductor wafer by its own weight on the supporting surface of the electrostatic chuck. Warpage caused by bringing the support surface into close contact with the force by force can be reduced.

Further, since the electrostatic chuck itself as the support fixes the semiconductor wafer, there is no generation of foreign matter such as abrasion powder due to fixing with the movable part, and the semiconductor wafer is not contaminated with the foreign matter. As a result, it is possible to prevent a defect due to warpage, a patterning defect, and the like in a wafer process, for example, a patterning process. Further, even if vibrations, shocks, or the like are applied to the carrier during the transfer, the semiconductor wafer that is fixed by suction does not rattle and can be safely transferred or stored.

The description of the above embodiment is based on the assumption that about +1.5 KV is applied to the electrostatic chuck 3a and about -1.5 KV is applied to the electrostatic chuck 3b.
KV is applied, but on the contrary, about -1.5 KV,
b, or 3a, 3b
Is provided with one electrode for each of about +1.5 KV (FIG. 4).
The same applies when applying about -1.5 KV.

[0022]

As described in detail above, according to the present invention,
By adsorbing and fixing the semiconductor wafer to the electrostatic chuck serving as a support, the semiconductor wafer can be supported and, at the same time, warpage caused by its own weight can be reduced. In addition, since there is no risk of contamination due to foreign matter, it is possible to prevent a transfer error or a process failure in a semiconductor process after transfer, thereby achieving a very useful effect in industry such as improvement in yield and improvement in productivity.

[Brief description of the drawings]

FIG. 1 is a principle diagram according to the present invention.

FIG. 2 is a front view of an embodiment according to the present invention.

FIG. 3 is a perspective plan view of FIG. 2;

FIG. 4 is an explanatory view of another embodiment in which one electrode is provided on an electrostatic chuck.

[Explanation of symbols]

 1: Carrier body 2: Semiconductor wafer 3: Electrostatic chuck 4: DC power supply 5: Switch 6: Suction force adjusting means (variable resistor)

Claims (3)

[Claims] At least one pair of electrostatic chucks provided on a carrier main body for sucking and supporting a peripheral portion of a semiconductor wafer, and a DC power supply applied to each of the pair of electrostatic chucks are provided. Characteristic carrier for semiconductor wafer. 2. The semiconductor wafer carrier according to claim 1, further comprising a switch for turning on / off a DC power supply. 3. The apparatus according to claim 1, further comprising an attraction force adjusting means for adjusting the supply power of the DC power supply.
A carrier for a semiconductor wafer as described in the above.