JP2539042B2 - Wafer carrier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Outline] A wafer carrier used for liquid immersion treatment of wafers, especially for cleaning with pure water, which suppresses waves generated when the wafer comes out of the water surface, and a pure water film adhered to the wafer surface in a water tank. A wafer carrier in which a plurality of wafers are arranged at intervals and housed and immersed in a liquid for the purpose of completely pulling down and reducing adhesion of foreign matter on the wafer after drying. , Each wafer is configured to be held perpendicularly to the liquid surface, and the line connecting the upper ends of the wafers is inclined with respect to the liquid surface, and the surface of the constituent member is oblique or perpendicular to the liquid surface To be Further, the constituent member is composed of two side plates facing each other and a plurality of wafer supporting members for connecting both side plates and supporting an edge portion of the wafer.

[Industrial applications]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer carrier used for liquid immersion treatment of a wafer, particularly for cleaning the wafer with pure water.

In recent years, with the miniaturization of semiconductor devices, advanced wafer cleaning technology has been required in the manufacturing process, and in particular, the technology of pulling a wafer out of pure water and drying it has become important. The present invention can be applied to this need.

[Conventional technology]

As the final drying technology for wafers, over the past few years, a technology has been developed in which the wafer is slowly pulled up from the pure water tank and the pure water film adhered to the wafer surface is pulled down into the water tank by the surface tension of water and dried. I've been

The conventional method of pulling a wafer from pure water is
It was heated to 60 ℃ and the pulling rate was 300 mm / min.

The wafer carrier used at this time is of Teflon type.
It is made of a resin called PFA and is structured so that the wafer is held by the spot contact formed on the wafer carrier.

FIGS. 4 (1) and 4 (2) are structural views of a conventional pure water cleaning wafer carrier.

In the figure, the wafer 2 is held by a wafer carrier 4, immersed in a pure water tank, slowly pulled up and dried.

The wafer carrier 4 is composed of side plates 41 and 44 and wafer supporting members 42 and 43.

The wafer carrier 4 in this case usually has members arranged parallel to the water surface, and the wafer arranging direction is also parallel to the water surface.

[Problems to be Solved by the Invention]

When pulling a wafer out of pure water, it is important to suppress vibrations and waves on the water surface. If the water surface moves unnecessarily during pulling up, the pure water film pulled down into the water tank again adheres to the wafer surface due to the corner surface tension, and foreign matter in the pure water remains on the wafer after drying.

 There are usually about 10 foreign substances in pure water / ml.

In particular, in wafer cleaning, the distance between wafers arranged to improve production efficiency is as narrow as about 6 mm, and when the edge of the wafer separates from the water surface, the water surface is pulled by the wafer due to surface tension, and the wafer reaches a certain height. When it comes, it breaks and vibrates, generating waves on the water surface.

When a plurality of wafers leave the water surface at the same time as in the conventional example, the generated wave becomes large.

An object of the present invention is to suppress the wave generated when the wafer separates from the water surface, and to completely lower the pure water film adhering to the wafer surface to the water tank, thereby reducing the adhesion of foreign matter on the wafer after drying. To do.

[Means for solving the problem]

A solution to the above problem is a wafer carrier in which a plurality of wafers are arranged and housed at intervals, and are immersed in a liquid. The connecting line is configured to be held at an angle with respect to the liquid surface, and the constituent member connects two side plates perpendicular to the liquid surface and both side plates and connects the edge portion of the wafer. The wafer supporting member is composed of three wafer supporting members that support the lower portion of the wafer. Achieved by a wafer carrier characterized by:

[Action]

 FIG. 1 is a principle diagram of the present invention.

In the figure, the wafer carrier 1 is configured so that members arranged parallel to the liquid surface are eliminated, and the arrangement direction of the wafers 2 is inclined with respect to the liquid surface.

As a result, the height of the wafer held by the carrier is gradually lowered (reduced by about 2 mm each), so when the upper edge of the wafer comes out of the liquid surface, there is a time lag one by one, and vibration is reduced. it can. The same applies when the lower edge of the wafer separates from the liquid surface.

Further, the wafer carrier itself also has no member parallel to the liquid surface, and is entirely inclined or perpendicular to the liquid surface so that it does not become wavy when pulled up from pure water. This is because a large area does not suddenly separate from the liquid surface.

Here, the difference between the present invention and a case where a normal carrier is held obliquely and pulled up will be described.

When the normal carrier is held obliquely and pulled up, the main surface of the wafer is not perpendicular to the liquid surface, and the air flow from the down-flow clean bench where the pure water tank is placed becomes parallel to the wafer. The wafer is hit diagonally and the air flow in the shaded area of the wafer is disturbed, resulting in a difference in drying speed. Does not occur.

〔Example〕

FIG. 2 is a block diagram of a pure water cleaning apparatus according to an embodiment of the present invention.

Also in the embodiment, as a processing example, the case of pure water cleaning is taken as an example like the conventional example.

In the figure, a wafer 2 is held by a wafer carrier 1, immersed in a pure water tank 3, slowly pulled up and dried.

FIGS. 3 (1) and 3 (2) are structural views of a pure water cleaning wafer carrier according to an embodiment of the present invention.

The wafer carrier 1 includes side plates 11 and 15 and wafer supporting members 12, 13 and 1
Composed of 4 and.

Here, the lower wafer supporting member 14 is provided so as to support the lower end of the wafer as shown in FIG.
As described above, the lower wafer supporting member 14 may be arranged above the lower end of the wafer. In this case, since the lower end of each wafer is gradually separated from the liquid surface, the generation of waves on the liquid surface is reduced.

Further, each wafer supporting member 12, 13, 14 is provided with a guide groove for supporting the wafer.

Each part of the wafer carrier 1 is arranged obliquely with respect to the water surface so that a large-area part does not separate from the water surface at one time.

Here, the temperature of pure water was 60 ° C., the flow rate was 1 m ³ / h, and the wafer carrier pulling rate was 300 mm / min.

By using such an asymmetrical wafer carrier, the generation of waves on the water surface is reduced and the adhesion of foreign matter to the wafer is reduced.

It was confirmed that the amount of adhering foreign matter was clearly reduced by the surface foreign matter inspection device using the scattering of laser light.

As the surface foreign matter inspection device, WM-3 type manufactured by Topcon was used.
The amount of foreign matter of 2 μm or more was inspected.

Numerical examples of the amount of adhered foreign matter in the embodiment for a 4-inch wafer are shown below in comparison with the conventional example.

Foreign matter size S M L Total Example 1 1 0 0 11 Conventional example 29 0 1 30 Where S is 0.2 to 0.5 μm, M is 0.5 to 1.0 μm, and L is 1.0 μm
That is all.

〔The invention's effect〕

As described above, according to the invention, it is possible to suppress the wave generated when the wafer separates from the water surface, and to completely lower the pure water film adhering to the wafer surface into the water tank, so that foreign matter on the wafer after drying can be prevented. Adhesion could be reduced.

[Brief description of drawings]

FIG. 1 is a principle diagram of the present invention, and FIG. 2 is a configuration diagram of a pure water cleaning apparatus according to an embodiment of the present invention. 3 (1) and 3 (2) are structural views of a pure water cleaning wafer carrier according to an embodiment of the present invention, and FIGS. 4 (1) and 4 (2) are conventional pure water cleaning wafer carrier structures. It is a figure. In the figure, 1 is a wafer carrier, 2 is a wafer, and 3 is a deionized water tank.

Claims (1)

(57) [Claims] 1. A wafer carrier for arranging a plurality of wafers arranged at intervals and immersing them in a liquid, wherein the constituent members connect each wafer perpendicularly to the liquid surface and connect the upper end of each wafer. The line is configured to hold at an angle with respect to the liquid surface, and the component connects the two side plates perpendicular to the liquid surface and both side plates and supports the edge of the wafer. The wafer support member for supporting the lower part of the wafer is formed by forming a groove for supporting the wafer in a flat plate-like member, and the main surface of the flat plate is perpendicular to the liquid surface. A wafer carrier characterized in that.