Device for holding wafer shaped articles
A device for holding wafer-shaped articles, such as semiconductor wafers, is equipped with a series of pins that are brought into contact with a peripheral edge of the wafer-shaped article, under control of a common gear ring or a series of conjointly operated gear sectors. In the regions of the gear ring or gear sectors engaging the pin assemblies, those elements are designed to yield more readily than other regions of the gear ring or gear sectors, to accommodate differential thermal expansion of the chuck components in the vicinity of the pin assemblies.
1. A device for holding a wafer-shaped article, comprising a plurality of movable contact elements having a projecting portion for contacting a wafer-shaped article and a mounting portion fitted within a body of said device, and a gear mechanism driving the contact elements in unison between a first position in which they contact a wafer-shaped article positioned on the device, and a second non-contact position, wherein the gear mechanism comprises, in at least one region engaging one of said plurality of contact elements, a construction that more readily yields to lateral displacement of said plurality of contact elements than other regions of said gear mechanism adjacent the at least one region wherein said gear mechanism has includes position on a body having teeth parallel to an elongated slot within said body.
2. The device according to claim 1 , wherein the contact elements are a series of pins that are conjointly movable from said second position to said first position.
3. The device according to claim 1 , wherein said body of the device is made of plastic.
4. The device according to claim 1 , wherein said device is a spin chuck in a process module for single wafer wet processing.
5. The device according to claim 2 , wherein the pins are arranged in a circular series, and each pin projects upwardly from a respective pivotal base along an axis parallel to and offset from a pivot axis of said pivotal base.
6. The device according to claim 1 , wherein said gear mechanism is a gear ring having teeth on a radially inward edge thereof, said teeth being in meshing engagement with corresponding teeth on said contact elements.
7. The device according to claim 1 , wherein said gear mechanism is a gear ring having teeth on a radially outward edge thereof, said teeth being in meshing engagement with corresponding teeth on said contact elements.
8. The device according to claim 1 , wherein said construction is configured such that the gear mechanism acts on the contact elements with a maximum force in the range of 5 to 20 N.
9. The device according to claim 1 , wherein said construction is a cut-out in said gear mechanism defining a narrowed region whose Young's modulus is less than that of said other regions.
10. The device according to claim 9 , wherein the cutout is enclosed such that no outer edge surface of said gear mechanism is thereby interrupted.
11. The device according to claim 9 , wherein the cut-out interrupts an edge surface of the gear mechanism such that the narrowed region is of a cantilever form.
12. The device according to claim 1 , wherein said construction is an insert fitted with a cavity of said gear mechanism, said insert comprising gear teeth in meshing engagement with corresponding teeth of said at least one contact element, said insert being urged into meshing engagement with said corresponding teeth by at least one resilient element, said at least one resilient element yielding to displacement of said at least one contact element in a direction toward said cavity.
13. The device according to claim 12 , wherein said at least one resilient element is at least one spring.
14. The device according to claim 12 , wherein said at least one resilient element is a body of elastomeric material fitted within said cavity.
15. A device for holding a wafer-shaped article, comprising a plurality of movable pin assemblies each having a projecting portion for contacting a wafer-shaped article and a mounting portion fitted within a body of said device, and a gear mechanism driving the pin assemblies in unison between a first position in which the projecting portions contact a wafer-shaped article positioned on the device, and a second non-contact position, wherein the gear mechanism comprises, in at least one region engaging one of said plurality of pin assemblies, means for accommodating lateral displacement of said plurality of pin assemblies more readily than in other regions of said gear mechanism adjacent the at least one region wherein said gear mechanism has includes position on a body having teeth parallel to an elongated slot within said body.