Substrate container with door gasket
Gaskets for wafer containers include a seal body and a retention projection. The retention projection includes a retention segment extending from the seal body, a compression relief segment extending from the retention segment, and a bead disposed at an end of the compression relief segment. The compression relief segment has a cross-sectional width less than a cross-sectional width of the retention segment. The bead has a shape including portion having a width greater than a cross-sectional width of the gland at a corresponding depth in the gland. The gasket can be provided in a wafer container or a door of the wafer container.
1. A door for a wafer container, comprising:
a door plate including a gland configured to receive a portion of a gasket; and
a gasket including a compressible material, the gasket including:
a seal body; and
a retention projection, the retention projection comprising:
a retention segment extending from the seal body, the retention segment having a cross-sectional width equal to or less than a cross-sectional width of the gland at a corresponding depth in the gland;
a compression relief segment extending from the retention segment, the compression relief segment having a cross-sectional width less than a cross-sectional width of the retention segment; and
a bead disposed at an end of the compression relief segment, the bead having a maximum cross-sectional width greater than a cross-sectional width of the gland at a corresponding depth in the gland.
2. The door of claim 1 , wherein the gasket has a retention force to insertion force ratio of 0.5 to 1.0, the retention force being a force required to remove the gasket from the gland, the insertion force being a force required to fully insert the retention projection into the gland.
3. The door of claim 1 , wherein when the door is attached to a wafer container, a conductance through the door joint is less than 0.02 L/s/atm.
4. The door of claim 1 , wherein the retention segment forms at least one half of the length of the retention projection.
5. The door of claim 1 , wherein the retention segment has a length that is at least twice a length of the compression relief segment.
6. The door of claim 1 , wherein the gasket is formed of a thermoplastic elastomer having a Shore A hardness of 50-80 durometer.
7. The door of claim 1 , wherein the cross-sectional width of the retention segment is between 5% and 15% smaller than the cross-sectional width of the gland where the retention segment meets the seal body.
8. The door of claim 1 , wherein the cross-sectional width of the bead at a widest point is between 5% and 12% larger than the cross-sectional width of the gland at a corresponding depth in the gland.
9. The door of claim 1 , wherein the cross-sectional width of the compression relief segment that is between 5% and 15% smaller than a cross-sectional width of the retention segment.
10. A front opening wafer container comprising:
a container body having an open front, the open front defined by a door frame;
a door configured to be attached to the door frame, the door including:
a door plate including a gland configured to receive a portion of a gasket; and
a gasket including a compressible material, the gasket including:
a seal body; and
a retention projection, the retention projection comprising:
a retention segment extending from the seal body, the retention segment having a cross-sectional width equal to or less than a cross-sectional width of the gland at a corresponding depth in the gland;
a compression relief segment extending from the retention segment, the compression relief segment having a cross-sectional width less than a cross-sectional width of the retention segment; and
a bead disposed at an end of the compression relief segment, the bead having a maximum cross-sectional width greater than a cross-sectional width of the gland at a corresponding depth in the gland,
wherein the gasket is configured to form a seal between the door and the door frame.
11. The front opening wafer container of claim 10 , wherein the gasket has a retention force to insertion force ratio of 0.6 to 1.0.
12. The front opening wafer container of claim 10 , wherein when the door is attached to a wafer container, a conductance through the door joint is less than 0.02 L/s/atm.
13. The front opening wafer container of claim 10 , wherein the retention segment forms at least one half of the length of the retention projection.
14. The front opening wafer container of claim 10 , wherein the retention segment has a length that it is at least twice a length of the compression relief segment.
15. The front opening wafer container of claim 10 , wherein the gasket is formed of a thermoplastic elastomer having a Shore A hardness of 60 to 90 durometer.
16. The front opening wafer container of claim 10 , wherein the cross-sectional width of the retention segment is between 5% and 15% smaller than the cross-sectional width of the gland where the retention segment meets the seal body.
17. The front opening wafer container of claim 10 , wherein the cross-sectional width of the bead at a widest point is between 5% and 12% larger than the cross-sectional width of the gland at a corresponding depth in the gland.
18. The front opening wafer container of claim 10 , wherein the cross-sectional width of the compression relief segment that is between 5% and 15% smaller than a cross-sectional width of the retention segment.