Single component gas diffusion component with variation of gas diffusion characteristics

Abstract

A gas diffusion system including a gas supply and a gas diffuser. In one example the gas diffuser includes an open end connected to the gas supply, a closed end, and a porous diffuser wall extending from the open end to the closed end and defining an interior cavity. The porous diffuser wall is formed of a single material, and has at least a first wall thickness and a second wall thickness between the interior cavity and an exterior of the porous diffuser wall, with the first wall thickness being thinner than the second wall thickness. A gas flow rate out of the porous diffuser at the first wall thickness is greater than a purge gas flow rate out of the porous diffuser at the second wall thickness.

Description

[0001] SINGLE COMPONENT GAS DIFFUSION COMPONENT WITH VARIATION OF GAS DIFFUSION CHARACTERISTICS

[0002] CROSS REFERENCE TO RELATED APPLICATIONS

[0003]

[0001] This patent application claims priority to and the benefit of the filing date of United States provisional patent application serial number 63 / 660,777 filed June 17, 2024 for a Single Component Gas Diffusion Component With Variation of Gas Diffusion Characters, the entire contents of which is incorporated herein by this reference.

[0004] RELATED FIELDS

[0005]

[0002] Gas diffusers such as used for purge gas output in a front opening universal pod.

[0006] BACKGROUND

[0007]

[0003] Gas diffusers in the semiconductor industry often require high purity and / or high precision gas delivery. In many applications, it may be desirable that a single gas diffuser deliver different amounts of gas in different location. One typical diffuser design used in the semiconductor industry in connection with a FOUP (front Opening Universal Pod) is a tubular shape with one open end and one closed end.

[0008]

[0004] To achieve desired gas diffusion in FOUP diffuser, typical current diffusers on market use two materials to achieve a dual gas flow profile. The two materials have different pore sizes, so the sections of the tube made with the different materials have different flow rates through the wall of the tube. The smaller pore size material section has a lower air flow rate through the tube wall and the larger pore size material has a higher flow rate through the tube wall. Figure 1 shows an example of a two-material diffuser. This diffuser is formed using a straight core pin and a straight cavity, and that combination produces a diffuser that has a constant wall thickness for the entire length of the part.

[0005] The two-material approach has drawbacks in application and production process. Its gas diffusion property is difficult to control and causes variation in different production lots. The two materials also generate purity issues and increase the cost. Moreover, the two-material approach limits the ability to customize and fully control the gas flow along the length of the diffuser.

[0009] SUMMARY

[0010]

[0006] We have developed improved gas diffusers that provide greater performance for the semiconductor industry's FOUR process and other purposes that use one material with a variation of wall thickness in different portions of the diffuser.

[0011]

[0007] The new diffusers use wall thickness to achieve this dual air flow with a single material. This can improve performance and reduce manufacturing complexity. This also allows custom air flow profiles using variable wall thickness patterns, providing a more effective way for such customization than being limited to two materials.

[0012]

[0008] In some implementations the diffusers use variable wall thickness with a single material (one pore size) to control air flow. This design allows for custom gas flow profiles and improved precision in the gas diffusion rates. In some implementations, a core pin that has multiple diameters or a diameter profile is used to produce a part with varying wall thickness along the length of the part. This will result in multiple gas flow sections of the part that can be matched to the testing data and allow engineers to balance the gas flow in the FOUR or other system requiring precision gas delivery.

[0013]

[0009] The multiwall thicknesses design provides FOUP designer with flexibility to design a FOUP device with desired gas distribution during different processes, such as storage, transportation or loading processes. A well-designed gas diffusor provides optimized gas distribution during these processes, reduces the potential contamination and improves the yield.

[0014] BRIEF DESCRIPTION OF FIGURES

[0015]

[0010] Figure 1 shows an example of a prior art two-material diffuser.

[0016] [Oil] Figure 2 shows an example of a gas diffuser with a dual wall thickness.

[0017]

[0012] Figure 3 shows the gas diffuser of Figure 2 as part of a gas diffusion system.

[0018]

[0013] Figure 4 shows another example of a gas diffuser with variable wall thickness.

[0019]

[0014] Figure 5 shows the gas diffuser of Figure 4 as part of a gas diffusion system.

[0020]

[0015] Figure 6 shows additional examples of gas diffusers.

[0021] DETAILED DESCRIPTION OF FIGURES

[0022]

[0016] Figure 2 shows an example of a gas diffuser. In this example the gas diffuser includes an open end 10 for connection to a gas supply, a closed end 12, and a porous diffuser wall 14 extending from the open end 10 to the closed end 12 and defining an interior cavity 16. Other variations in form are also possible. For instance, the gas diffuser could be tubular with two open ends.

[0023]

[0017] In this example the porous diffuser wall 14 is formed of a single material. In some implementation the single material may be a sintered material. The single material may be a single porous plastic such as sintered polyethylene, sintered ultrahigh molecular weight polyethylene and polypropylene. In some implementations, "single material" may refer to a material with a distinguished chemical structure and from the same lot from a vendor that has been formed at the same time. In one particular implementation the single material is same lot polyethylene. In some instances the same lot polyethylene may be 95% wt polyethylene, 98% wt polyethylene, 99% wt polyethylene, 99.5% wt polyethylene, or 99.9% wt polyethylene.

[0018] The composition of the single material may be substantially uniform throughout the porous diffuser wall 14, and an average pore size of the porous diffuser wall 14 is substantially uniform throughout the porous diffuser wall 14. For instance, the average pore size of the porous diffuser wall 14 may vary by less than 5% throughout the porous diffuser wall 14.

[0024]

[0019] In this example the porous diffuser has a length between the open end 10 and the closed end 12 between 150 mm and 500 mm.

[0025]

[0020] In this example the porous diffuser has an average pore size between 10 microns and 50 microns (or 40 microns in some implementations) and has an average porosity between 25% and 50% (or 45% in some implementations). The pore size and porosity may be measured by Mercury Porosimeter. The average pore size and average porosity may vary by less than 5%, less than 3%, or less than 1% along the length of the porous diffuser. In other words, the single component material may have no distinguishable variation in pore size and pore volume in different portions of the diffuser.

[0026]

[0021] As shown in the example of Figure 2 the porous diffuser wall includes a first wall thickness A and a second wall thickness B between the interior cavity 16 and an exterior of the porous diffuser wall 14. The first wall thickness A is closer to the open end 10 of the porous diffuser than the second wall thickness B and is thinner than the second wall thickness B. The first wall thickness A is thinner than the second wall thickness B. In this example, and as shown in Figure 3, when the gas diffuser is connected to a gas supply (labeled gas in), a gas flow rate out of the porous diffuser at the first wall thickness is greater than a gas flow rate out of the porous diffuser at the second wall thickness. In this manner, the wall thickness can be used as a precise control for gas flow rate at different parts of the gas diffuser. In some implementations the gas flow rate out of the diffuser at the first wall thickness A may be at least 10% greater than the gas flow rate out of the diffuser at the second wall thickness B. In some implementations the gas flow rate out of the diffuser at the first wall thickness A is at least 25% greater than the gas flow rate out of the diffuser at the second wall thickness B.

[0027]

[0022] For some gas diffusion systems (e.g. a gas diffusion system of a FOUR), it may be particularly advantageous for the first wall thickness A to be between 1 and 3 mm and the second wall thickness B to be between 3.5 and 5 mm. In four particular examples the first wall thickness A may be 1.4, 1.65, 1.91, or 2.16 mm and the second wall thickness B may be 4.06 mm, with an outside diameter of about 11.94 mm (which in other implementations may be between 5 and 15 mm) and a length of 254 mm (which in other implementations may be between 150 and 500 mm).

[0028]

[0023] In the example of Figures 2 and 3 the gas diffuser has a stepped change in wall thickness. Figure 4 shows another example of a gas diffuser that includes a continuous change in wall thickness (which may be along the entire length of the interior or in some implementations just along a portion or portions of the interior). As shown in Figure 5, the diffuser of Figure 4 may produce a continuous or relatively continuous variation in flow rate out along its length.

[0029]

[0024] Figure 6 shows additional examples of gas diffusers of the present patent in comparison to a single thickness gas diffuser. Gas diffusers of the present patent may have multiple wall thickness, such as two distinguishable wall thicknesses, three distinguishable wall thicknesses, four distinguishable wall thicknesses, five distinguishable wall thicknesses, or more. The minimum wall thickness is above 1 mm and maximum wall thickness is less than 5 mm in some particular implementations. Optionally, the difference between the different wall thickness is minimum 0.5 mm. The length of the diffusor could be any length that shows good strength. Specifically from 150 mm to 500 mm, or from 200 mm to 400 mm.

Claims

Claims:

1. A gas diffusion system comprising: a gas supply; a gas diffuser comprising: an open end connected to the gas supply; a closed end; a porous diffuser wall extending from the open end to the closed end and defining an interior cavity; wherein the porous diffuser wall is formed of a single material; wherein the porous diffuser wall comprises a first wall thickness and a second wall thickness between the interior cavity and an exterior of the porous diffuser wall; wherein the first wall thickness is closer to the open end of the porous diffuser than the second wall thickness; and wherein the first wall thickness is thinner than the second wall thickness; wherein a gas flow rate out of the porous diffuser at the first wall thickness is greater than a purge gas flow rate out of the porous diffuser at the second wall thickness.

2. The gas diffusion system of claim 1 wherein single material is a sintered material.

3. The gas diffusion system of claim 1 wherein the single material is a sintered porous plastic.

4. The gas diffusion system of claim 3 wherein the porous diffuser comprises a length between the open and closed ends between 150 mm and 500 mm.

5. The gas diffusion system of claim 4 wherein the porous diffuser comprises an average pore size between 10 microns and 50 microns and has an average porosity between 25% and 50%.

6. The gas diffusion system of claim 5 wherein the average pore size and the average porosity varies by less than 5% along the length of porous diffuser.

7. The gas diffusion system of claim 4 wherein the first wall thickness is between 1 and 3 mm, wherein the second wall thickness is between 3.5 and 5 mm.

8. The gas diffusion system of claim 2 wherein a composition of the single material is substantially uniform throughout the porous diffuser wall.

9. The gas diffusion system of claim 2 wherein an average pore size of the porous diffuser wall is substantially uniform throughout the porous diffuser wall.

10. The gas diffusion system of claim 9 wherein an average pore size of the porous diffuser wall varies by less than 5% throughout the porous diffuser wall.

11. The gas diffusion system of claim 9 wherein the gas flow rate out of the diffuser at the first wall thickness is at least 10% greater than the gas flow rate out of the diffuser at the second wall thickness.

12. The gas diffusion system of claim 9 wherein the gas flow rate out of the diffuser at the first wall thickness is at least 25% greater than the gas flow rate out of the diffuser at the second wall thickness.

13. The gas diffusion system of claim 1 wherein the porous diffuser wall comprises a third wall thickness, wherein the third wall thickness is located between the first wall thickness and the second wall thickness, wherein the third wall thickness is thicker than the first wall thickness and thinner than the second wall thickness, and wherein a purge gas flow rate out of the diffuser at the third wall thickness is greater than the purge gas flow rate out of the diffuser at the second wall thickness and is lesser than the purge gas flow rate out of the diffuser at the first wall thickness.

14. The gas diffusion system of claim 13 wherein the purge gas flow rate out of the diffuser at the third wall thickness is at least 5% greater than the purge gas flow rate out of the diffuser at the second wall thickness and is at least 5% lesser than the purge gas flow rate out of the diffuser at the first wall thickness.

15. The gas diffusion system of claim 13 wherein the porous wall diffuser comprises a stepped change in wall thickness.

16. The gas diffusion system of claim 13 wherein the porous wall diffuser comprises a continuous change in wall thickness through at least a portion of the porous wall diffuser.

17. A purge gas diffuser comprising: an open end configured for connection to a purge gas supply; a closed end; and a porous diffuser wall extending from the open end to the closed end and defining an interior cavity; wherein the porous diffuser wall is formed of a single material; wherein the porous diffuser wall comprises a first wall thickness and a second wall thickness between the interior cavity and an exterior of the porous diffuser wall; wherein the first wall thickness is closer to the open end of the porous diffuser than the second wall thickness; and wherein the first wall thickness is thinner than the second wall thickness.

18. The purge gas diffuser of claim 17 wherein single material is a sintered material.

19. The purge gas diffuser of claim 18 wherein a composition of the single material is substantially uniform throughout the porous diffuser wall.

20. The purge gas diffuser of claim 18 wherein an average pore size of the porous diffuser wall is substantially uniform throughout the porous diffuser wall.

21. The purge gas diffuser of claim 20 wherein an average pore size of the porous diffuser wall varies by less than 5% throughout the porous diffuser wall.

22. The purge gas diffuser of claim 20 wherein the porous diffuser wall comprises a third wall thickness, wherein the third wall thickness is located between the first wall thickness and the second wall thickness, and wherein the third wall thickness is thicker than the first wall thickness and thinner than the second wall thickness.

23. The purge gas diffuser of claim 20 wherein the porous wall diffuser comprises a stepped change in wall thickness.

24. The purge gas diffuser of claim 20 wherein the porous wall diffuser comprises a continuous change in wall thickness through at least a portion of the porous wall diffuser.

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