Edge seal wafer bumping for Injected molded solder (IMS)
Publication Date: 2014-Apr-07
The IP.com Prior Art Database
Principles of the present invention provide techniques for wafer bumping using injection molded solder (IMS). An exemplary apparatus, according to an aspect of the invention, includes a solder reservoir and a portion of compliant material. A raised ring around the outside of the wafer increases the force of the compliant material that is mounted on the IMS head. The ring displaces the compliant material preventing solder to flow through the slot opening in the compliant material. The compliant material has an angled slot that when in contact with the raised surface seals the slot preventing solder to flow in that location.
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Edge seal wafer bumping for Injected molded solder (
The present invention generally relates to the electrical and electronic arts and, more particularly, to injection molded solder techniques, and solder bumps deposition on wafers. Disclosed is the method to solve the molten solder leaking at the edge of round wafer by using the a raised ring around the outside of the wafer when the straightly moved injection molded head is used.
As the rectangular head moves across the circular surface, the contact area of the head with the wafer varies. This allows gaps where molten solder can leak between the wafer and the surrounding fixture. What is needed is a method and apparatus to minimize this leakage.
Figure 1 shows the side view of IMS head, elastomer of IMS head, Si wafer, a raised ring (black color, solder seal). There are solder materials inside the solder seal, but solder is not injected outside the solder seal.
Figure 2 shows how the raised seal edge pressed the compressed foam and prevent solder leaking. When the IMS head is pressed, the seal edge pressed the foam, and the compressed foam prevent solder leaking outside of the seal edge.
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Figure 3 shows top view of IMS head movement on the raised ring (seal egde) around the outside of the wafer. As shown in Figure 3, the solder is injected only inside the seal edge and there is no leakage of solder outsides of the seal edge .
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