JP2003142557A - Wafer carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wafer carrier in which particles are prevented from whirling up. SOLUTION: An operating plane 13 is disposed oppositely to a wafer 30 in proximity to the surface thereof and a gas flow is generated between the operating plane 13 and the wafer 30 by supplying gas from a gas inlet 14 and discharging it from a gas outlet 18. A ring-like guide 22 is provided to entirely surround the outer circumference of a float chuck 10 for noncontact suction holding the wafer 30 by pressure drop due to the gas flow. The ring-like guide 22 has an inside diameter capable of containing the outer circumference of the wafer 30 and guides the wafer 30. At the same time, the space 23 between the outer circumference of the float chuck 10 and the inside of the guide 22 is evacuated by an evacuating means 25 so that the leakage of gas from the float chuck 10 is blocked thus preventing particles from whirling up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer transfer device, and more particularly, to a wafer transfer device using a float chuck that sucks and holds a wafer in a non-contact manner.

[0002]

2. Description of the Related Art A float chuck has an operating surface facing a surface of a wafer to be transported, and has a gas inlet and a gas outlet opened on the operating surface. The gas is caused to flow between the working surface and the surface of the wafer by causing the gas to flow in through the gas inlet while being closely opposed to each other and exhausting the gas from the gas outlet, and to reduce the pressure drop due to the flow of the gas. This float chuck is used to suck and hold the wafer in a non-contact manner with the operating surface. Since this float chuck can hold the wafer in a non-contact manner, it is suitable for transporting the wafer which is averse to particle adhesion and damage.

[0003]

However, in this float chuck, the gas flowing from the gas inflow port between the working surface and the wafer leaks out without being completely exhausted to the gas outflow port. The particles above may be rolled up.

An object of the present invention is to provide a wafer transfer device capable of suppressing the above-mentioned particle winding.

[0005]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides an operating surface facing a surface of a wafer to be transported, and a gas inlet and a gas outlet respectively opened on the operating surface. A float chuck for causing the working surface to closely face the surface of the wafer to allow a gas to flow in from the gas inlet and to exhaust the gas from the gas outlet to hold the wafer in a non-contact manner. Between the outer circumference of the float chuck and the inside of the guide, a ring-shaped guide provided so as to surround the outer circumference of the float chuck and having an inner diameter capable of accommodating the outer circumference of the wafer sucked and held in a non-contact manner. And an exhaust means for exhausting the space.

According to the present invention, the wafer is held at a predetermined position by the ring-shaped guide, and the gas leaked to the outside of the float chuck is a space between the outer circumference of the float chuck and the inside of the ring-shaped guide. Exhausted from
Since it does not leak out of the guide, it is possible to prevent particles from rolling up.

The evacuation means is constructed so that the evacuation amount can be adjusted, so that the outer circumference of the float chuck and the inner side of the ring-shaped guide are set to the minimum necessary flow rate for suppressing the leakage of gas from the float chuck. It is preferable to further suppress the inflow of the external atmosphere into the space between.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIG. 10 is a float chuck and 30 is a wafer. The float chuck 10 is
Pad portion 1 extending downward in FIG. 1, respectively
1 and a hood portion 12, and the tip surface of the pad portion 11 (see FIG.
In FIG. 1, the lower end surface thereof constitutes an operating surface 13 composed of a flat surface facing the surface of the wafer 30 (the upper surface in FIG. 1).

At the center of the working surface 13, a concave portion is formed at the lower end.
Cushion chamber 15 whose opening constitutes the gas inlet 14
Is provided. This cushion chamber 15 has a flow
Gas provided at the center of the main body 10A of the chuck 10.
Air through the supply path 16, N _TwoOr H_TwoGas supply source such as
It is connected to 17.

1 is provided between the pad portion 11 and the hood portion 12.
It is divided into one ring or multiple, and the lower end is the gas outlet 1.
8 is formed, and the recess 19 is connected to an exhaust means 21 such as a vacuum pump through an exhaust passage 20 provided in the main body 10A.

A ring-shaped guide 22 is provided on the outer periphery of the float chuck 10 constructed as described above, that is, on the outer periphery of the hood portion 12, so as to surround the entire outer periphery. The lower end of the guide 22 projects downward by a length less than the thickness of the wafer 30 from a distance h between the surface of the wafer 30 and the operating surface 13 capable of suction-holding the wafer 30 by the float chuck 10.
Further, the inner diameter of the lower end of the guide 22 is formed to accommodate the outer periphery of the wafer 30 with an appropriate gap.

A ring-shaped space 23 formed between the outer periphery of the hood portion 12 and the inside of the guide 22 is connected to an exhaust means 25 such as a vacuum pump through an exhaust port 24.
As shown in the drawing, the exhaust means 25 is provided separately from the exhaust means 21 connected to the recess 19 of the float chuck 10, and is configured such that the exhaust amount can be appropriately adjusted and set separately from the float chuck 10. . Note that the space 23 may be connected to the exhaust means 21 via an exhaust amount adjusting means (not shown), without being limited to this example.

Next, the operation of the float chuck 10 (hereinafter referred to as the present apparatus) provided with the guide 22 will be described. The apparatus is moved by a robot or the like (not shown) above the wafer 30 placed on a wafer support member (not shown), and the working surface 13 is brought closer to the surface of the wafer 30 by a suction-holdable distance h. At the same time as supplying gas such as air or N ₂ or H ₂ from 17 to the gas supply passage 16, the exhaust means 21 and 25 connected to the exhaust passage 20 and the exhaust port 24 are operated respectively.

The gas supplied to the gas supply passage 16 flows through the cushion chamber 15 from the gas inlet 14 between the working surface 13 and the surface of the wafer 30, passes through the space, and is recessed from the gas outlet 18. The gas is exhausted by the exhaust means 21 via the exhaust passage 19 and the exhaust passage 20. The working surface 13 and the wafer 30
The pressure of this portion is reduced by the flow of gas between the wafer 30 and the surface of the wafer, and the wafer 30 is suction-held on the working surface 13 in a non-contact manner.

At this time, from the gas inlet 14 to the working surface 13
A part of the gas flowing between the surface of the wafer 30 and the surface of the wafer 30,
Even if the gas leaks from the gas outlet 18 to the outside of the hood 12 without being exhausted by the exhaust means 21 through the recess 19 and the exhaust passage 20, the leaked gas is a ring provided over the entire outer circumference of the hood 12. The space 23 is exhausted by the exhaust means 25 through the exhaust port 24.

Therefore, it is possible to prevent the particles from being wound up due to the outflow of gas from the float chuck 10.

Exhaust from the ring-shaped space 23 by the exhaust means 25 is set so that the flow rate thereof is slightly higher than the flow rate of the gas leaking out from the hood portion 12, so that the gas ( It is preferable to suppress excessive inflow of the atmosphere in the place where the present apparatus is used) and to suppress the particles from being wound up due to the inflow of gas from the outside.

[0018]

As described above, according to the present invention, a ring-shaped guide having an inner diameter capable of accommodating the outer circumference of a wafer is provided so as to surround the outer circumference of the float chuck, and the space inside the guide is The addition of a simple structure of providing an exhaust means for exhausting can suppress the winding of particles.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

[Explanation of symbols]

10 float chuck 11 Pad part 12 Hood 13 Working surface 14 gas inlet 15 Cushion room 16 gas supply channels 17 Gas supply source 18 gas outlet 19 recess 20 exhaust path 21, 25 Exhaust means 22 Guide 23 space 24 exhaust port 30 Waha.

Claims (2)

[Claims] 1. An operating surface facing a surface of a wafer to be transported, and a gas inlet and a gas outlet opening on the operating surface, respectively, the operating surface being closely opposed to the surface of the wafer. A float chuck that allows a gas to flow in from the gas inlet and exhausts the gas from the gas outlet to suck and hold the wafer in a non-contact manner; and a non-contact type float chuck provided so as to surround the entire outer circumference of the float chuck. A ring-shaped guide having an inner diameter capable of accommodating the outer circumference of the wafer sucked and held by the exhaust chuck, and exhaust means for exhausting the space between the outer circumference of the float chuck and the inside of the guide. Wafer transfer device. 2. The wafer transfer apparatus according to claim 1, wherein the evacuation unit is configured to be capable of adjusting an evacuation amount.