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US 9,793,152 B2Granted
Use of vacuum chucks to hold a wafer or wafer sub-stack
AssigneeHeptagon Micro Optics Pte. Ltd.
InventorsHartmut Rudmann, Stephan Heimgartner, John A. Vidallon
Life of this patent
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Abstract
Techniques are described for holding a wafer or wafer sub-stack to facilitate further processing of the wafer of sub-stack. In some implementations, a wafer or wafer sub-stack is held by a vacuum chuck in a manner that can help reduce bending of the wafer or wafer sub-stack.
Claims20
A method of forming features on a wafer using a replication process, the method comprising:
- placing a wafer on a vacuum chuck, wherein a first surface of the wafer that faces the vacuum chuck includes features that project toward the vacuum chuck, and wherein the vacuum chuck includes a central recessed surface on which a silicone mat is disposed;
- applying pressure to a second surface of the wafer on a side of the wafer opposite its first surface such that the features of the wafer on its first surface are in contact with the silicone mat, and wherein part of the first surface of the wafer near its periphery is in contact with an elevated section of the vacuum chuck that includes a vacuum channel;
- generating a vacuum using the vacuum channel so as to hold the wafer to the vacuum chuck;
- and
- subsequently bringing a replication tool into contact with the second surface of the wafer to form features on the second surface of the wafer using a replication process.
2 more elements
A method of forming features on a wafer, the method comprising:
- placing a wafer on a vacuum chuck, wherein a first surface of the wafer that faces the vacuum chuck includes features that project toward the vacuum chuck, and wherein the vacuum chuck includes a recessed surface on which a non-sticky, soft, elastic and non-abrasive material is disposed such that the features of the wafer are in contact with the material on the recessed surface of the vacuum chuck, and wherein portions of the first surface of the wafer near its periphery are in contact with an elevated section of the vacuum chuck that includes a vacuum channel;
- generating a vacuum to hold the wafer to the vacuum chuck;
- and
- subsequently bringing a replication tool into contact with a second surface of the wafer on a side of the wafer opposite its first surface to form replicated features on the second surface of the wafer.
1 more element
A method of forming a wafer stack, the method comprising:
- using a vacuum chuck to hold a first wafer, wherein the vacuum chuck includes a first surface with a vacuum groove, wherein the first surface of the vacuum chuck includes a central region that is encircled by the vacuum groove and an outer region that encircles the vacuum groove, and wherein the central region and the outer region of the first surface of the vacuum chuck are at substantially the same height, wherein a first surface of the first wafer that faces the vacuum chuck includes a plurality of features thereon that contact the central region of the vacuum chuck's first surface, the first surface of the first wafer further including a sealing ring that contacts the outer region of the vacuum chuck's first surface;
- and
- bringing a second wafer into contact with a second surface of the first wafer, wherein the second surface of the first wafer is on a side of the first wafer opposite its first surface.
Dependencies are inferred from the claim text.