TWM526559U - Wafer cassette - Google Patents

Description

Wafer box

It belongs to a semiconductor wafer carrier and does not limit the number and size of wafers in the container. It is a wafer cassette with multiple vents.

Wafers must be transported and stored in a highly clean environment to avoid contamination by particulate dust or gaseous impurities. With the development of high-definition and large-volume wafer products, the higher the pollution probability, and the extremely small amount of pollution that occurs during wafer transportation or storage, if not removed in time, it is easy to continue to accumulate into higher concentrations. The contamination creates wafer defects and reduces yield.

Therefore, maintaining the high cleanness of the wafer cassette is an important issue in the semiconductor manufacturing industry. The design of the wafer cassette can be considered from several aspects, including the blowing of the clean gas, the amount of gas blowing and the angle when the wafer cassette is transferred or opened in the clean room during the process, which will affect the internal environment of the wafer cassette. Cleanliness; and when the wafer cassette is cleaned, the moisture remaining in the wafer cassette is efficiently discharged, which also affects the cleanliness.

In order to remove moisture, particles and other substances in the wafer cassette, the main way at this stage is to improve the cleanliness by blowing clean gas. Please refer to Figure 1, which is a known wafer cassette structure, wafer cassette 60 The bottom portion has an air inlet hole 80 through which clean gas can be sent into the casing 60 to keep the wafer 70 in the casing clean.

However, such a known wafer cassette structure has problems such as uneven air flow rate and blown corners. In view of this, the Republic of China Patent Publication No. TW201136814A1 "Poly-environment porous wall for polyester gas penetration" That is to say, an improvement in the structure of the wafer cassette is achieved by providing a tower-like structure having a plurality of holes at the bottom of the wafer cassette, and allowing the flow of the clean gas to pass through the tower-like structure into the inside of the wafer cassette to adjust the volume of the gas discharge. And pressure to achieve the effect of airflow homogenization.

At present, although this design can achieve the rectification effect, the gas emission is small. When the wafer size becomes larger, the gas flow rate may not be sufficient to meet the high-specified cleanliness requirement, so it is necessary to further propose the structural improvement of the wafer cassette. To meet the stringent cleanliness requirements of future large-size wafers.

The present invention relates to a wafer cassette having a porous structure, the structure of which is designed as follows: a main structure having an open end, a closed end, a bottom and a top; at least one first air inlet, disposed at the bottom and close to a closed end position; a porous structure connected to the bottom and the top and disposed adjacent to the closed end; and a plenum formed by the closed end, the porous structure, the bottom and the top.

The gas-filled chamber formed by the porous structure and the closed end, the bottom and the top of the wafer cassette will cause the gas filled into the wafer cassette to be temporarily retained and deposited, and then blown to the wafer placement position through the porous structure.

The porous structure of the present invention is not a tubular or tower-shaped design, and can provide a large volume of airflow, increase the gas discharge rate and flow rate, and is more suitable as a carrier for large-sized wafers than conventional wafer cassettes.

10‧‧‧Main structure

12‧‧‧Open end

14‧‧‧Closed end

16‧‧‧ bottom

18‧‧‧ top

20‧‧‧ wafer

30‧‧‧First air intake

32‧‧‧First airflow

40‧‧‧Porous structure

42‧‧‧Air chamber

60‧‧‧ box

70‧‧‧ wafer

80‧‧‧Air intake

1 is a schematic view of a known wafer cassette structure; FIG. 2A is a schematic structural view of an embodiment of the present invention; FIG. 2B is a schematic view of a flow direction of an embodiment of the present invention.

One of the purposes of the present invention is to provide a wafer cassette that can accommodate a large air flow. Please refer to FIG. 2A, which is a schematic structural view of an embodiment of the present invention. The main structure 10 of the wafer cassette can be divided into an open end 12, a closed end 14, a bottom 16 and a top 18. The wafer 20 is received therein, and the main structure 10 includes at least one first air inlet 30 disposed at the bottom 16 And adjacent to the closed end 14; a porous structure 40 coupled to the bottom portion 16 and the top portion 18 and disposed adjacent the closed end 14; and formed by the closed end 14, the porous structure 40, the bottom portion 16, and the top portion 18. A gas chamber 42.

Wherein, the porous structure 40 has at least three pore diameters, and in the present embodiment, the diameter of each of the at least three pore diameters is required to be between 0.05 and 50 micrometers (μm), and the total gas output area is required to be greater than 0.12. Square meters to form a porous structure with a large outflow.

Further, the material of the porous structure 40 may be sintered ceramic or sintered metal, or sintered high density polyethylene or sintered ultra high molecular polyethylene.

The edge of the porous structure 42 is connected to the closed end 14, the bottom 16 and the top 18 to form the gas-receiving chamber 42, thereby providing a full-face porous structure 42 for effectively improving the gas generated by the conventional tower-shaped or tubular gas-exhausting structure. Insufficient traffic.

Please refer to FIG. 2B, which is a schematic diagram of the airflow direction of an embodiment of the present invention to further illustrate the influence of the structure of the wafer cassette on the gas flow direction in the cartridge. From the clean room The clean gas may enter the gas plenum 42 from the first gas inlet hole 30, first forming a vertical upward first gas flow 32, and the first gas flow 32 will be formed in the gas plenum 42 to form about 1,000 Pa (Pa) to 200,000. After the gas pressure of the Pa (Pa), the clean gas is uniformly discharged gradually from at least three pore sizes of the porous structure 40.

In the foregoing embodiment, the at least one first air inlet hole 30 may have a hole diameter of 1 to 50 mm, which is suitable for the existing clean room air supply pipe specification, and avoids an increase in the manufacturing process cost.

The at least one first air inlet hole 30 may also be provided with a filter film to ensure that the gas entering the main body structure 10 through the first air inlet hole 30 is in a highly clean state.

The created wafer cassette can provide large flow and uniform clean gas, especially suitable for large wafer carriers of 12吋 or more, and the structure design conforms to the existing clean room specifications, and can be implemented without changing the process equipment. .

10‧‧‧Main structure

12‧‧‧Open end

14‧‧‧Closed end

16‧‧‧ bottom

18‧‧‧ top

20‧‧‧ wafer

30‧‧‧First air intake

40‧‧‧Porous structure

42‧‧‧Air chamber

Claims (8)

A wafer cassette comprising: a main body structure having an open end, a closed end, a bottom and a top; at least one first air inlet disposed at the bottom and adjacent to the closed end; a porous structure Connected to the bottom and the top, and disposed adjacent to the closed end; and a plenum formed by the closed end, the porous structure, the bottom, and the top. The wafer cassette of claim 1, wherein the porous structure has at least three apertures. The wafer cassette of claim 2, wherein each of the at least three apertures has a diameter between 0.05 and 50 microns. The wafer cassette of claim 2, wherein the at least three apertures form a total outlet area greater than 0.12 square meters. The wafer cassette of claim 1, wherein the at least one first air inlet has a hole diameter of 1 to 50 mm. The wafer cassette of claim 5, wherein the at least one first air inlet is further provided with a filter film. The wafer cassette of claim 1, wherein the porous structure is made of sintered ceramic or sintered metal. The wafer cassette according to claim 1, wherein the porous structure is made of sintered high-density polyethylene or sintered ultra-high molecular polyethylene.