Wafer carrier

Description

BACKGROUND

The invention relates to a wafer carrier, and in particular to a wafer carrier having a top plate or a coated layer within the carrier preventing release of organic materials.

Semiconductor manufacturing includes many processes such as oxidation, diffusion, lithography, etching, CVD, and others. Each product wafer produced by CMOS process has many critical layers functioning to avoid yield loss. Currently, in order to prevent external contamination, wafers are put into wafer carriers for transportation during the semiconductor processes.

FIG. 1 is a diagram showing a conventional wafer carrier. As shown, a conventional wafer carrier 10 comprises a container 11 to hold two wafers 121,122. The wafers 121, 122 are arranged inside the wafer carrier 10, protected from external contamination. However, the container 11, comprising poly carbonate (PC), may release organic material or powder to chemically interact with the product wafers, inducing serious yield loss within some critical layers such as gate-oxide layers, poly layers, and others.

To ensure the product yield of the product wafers, it is important to develop a wafer carrier generating no harmful organic materials.

SUMMARY

Accordingly, the invention provides a wafer carrier. The wafer carrier includes a container and a plate, wherein the container carries at least one wafer, and the plate is disposed in the vicinity of the upper portion of the container.

DESCRIPTION OF THE DRAWINGS

The invention can be more fully understood by reading the subsequent detailed description and examples with references made to the accompanying drawings, wherein:

FIG. 1 depicts a conventional wafer carrier;

FIG. 2 depicts an embodiment of a wafer carrier;

FIG. 3A depicts another embodiment of the wafer carrier; and

FIG. 3B is a cross-section along A-A line in FIG. 3A.

DETAILED DESCRIPTION

A wafer carrier is described in greater detail in the following. FIG. 2 is a diagram of an embodiment showing a wafer carrier. In this embodiment, the wafer carrier 20 comprises a container 22 holding two wafers 221, 222 and a plate 21, having an inner wall (not shown). The wafer carrier 20 is a front opening unified pod (FOUP). Moreover, the container 22 is for carrying twenty-five wafers, to execute semiconductor processes and usually holds product wafers 221, 222. Since the container 22 comprises poly carbonate (PC), the container 22 may release organic material or powder which may interact with the product wafers, inducing serious yield loss of the product wafers. Because the wafer 221 is placed in the highest position of the container 22, the top wafer 221 receives more debris than other wafers. This circumstance can result in serious yield loss of the top wafer 221, particularly in some critical layers of the wafer such as gate-oxide, poly layer deposition, etc.

Thus, the plate 21 is disposed in the vicinity of the upper portion of the container 22 to protect the product wafers from contamination by the organic materials of the container 22, especially the top wafer 221. As shown in FIG. 2, the plate 21 is mounted in the upper portion of the container 22. Preferably, the plate 21 is longer than the diameter of the wafer to fully cover the top wafer 221. Furthermore, the plate 21 may comprise quartz, PVDF, silicon, ceramic, or any other suitable materials not releasing organic materials.

FIG. 3A is a diagram of another embodiment of a wafer carrier. Referring to FIGS. 3A, a wafer carrier 30 comprises a container 11′ holding two wafers 321,322, having an inner wall (not shown). FIG. 3B is a cross-section along A-A line in FIG. 3A. Referring to FIG. 3B, the container 11′ is a two-layered structure and comprises an inner wall 31 and a layer 32. As mentioned before, since the inner wall 31 of the container 11′ is made of poly carbonate, the inner wall 31 may release organic materials, damaging the product wafers 321,322. By coating the layer 32 on the inner wall 31, the organic debris from the inner wall 31 is properly controlled.

Moreover, the layer 32 is coated at least on the inner wall 31, at the upper portion of the container 11′, preferably the layer 32 is fully coated on the inner wall 31 of the interior of the container 11′. Additionally, in this embodiment, the layer 32 is a TiO₂ film. When water exists on the surface of TiO₂ with sufficient light, Hydroxyl Radical (OH.) can be produced, decomposing organic matter that attaches to TiO₂. Preferably, the TiO₂ layer is coated by chemical vapor deposition process or sputter process. In other words, the inner wall 31 is fully covered by the layer 32, whereby organic materials of the inner wall 31 can be decomposed, avoiding yield loss of the product wafers. When fully covered with the layer 32, the container 11′ fully protects the product wafers from top to bottom.

As previously described, the invention provides a wafer carrier having a plate on the inner top portion of the carrier or an inner layer coated within the carrier preventing organic material release therefrom. Additionally, through the arrangement of the wafer carrier of the invention, organic contamination is effectively restrained so that the production yield is improved during all kinds of processes.

While the invention has been described by way of example and in terms of preferred embodiment, it is to be understood that the invention is not limited thereto. To the contrary, it is intended to cover various modifications and similar arrangements (as would be apparent to those skilled in the art). Therefore, the scope of the appended claims should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements.