Oversized Interposer via Multistep Lithographic Stitching
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Solution Overview
Problem
Conventional interposers for integrated circuits (ICs) are limited in size by the maximum field size of a lithographic scanner, restricting the number and size of semiconductor dies that can be accommodated in a single package.
Innovation Solution
The development of an oversized interposer is achieved through multistep imaging and the use of a mask set with multiple masks, allowing for the creation of interposers with dimensions greater than the conventional reticle field size limits by lithographically stitching together image slices with sufficiently large feature sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If conventional lithographic scanning is used, then manufacturing precision is maintained within the reticle field size limit, but the interposer size is restricted to maximum dimensions
Solution Approach 1:
The interposer is divided into multiple image slices that are printed separately and then stitched together. Each slice is printed within the reticle field size limit, but the collection of slices forms a larger interposer structure, effectively overcoming the reticle size constraint while maintaining manufacturing precision for each individual slice
Solution Approach 2:
The patent transitions from printing entire interposers in a single reticle field to printing multiple slices across different reticle fields and assembling them in a sequential manner. This dimensional approach to manufacturing allows the final interposer to exceed the maximum reticle dimensions while each printing step remains within precision limits
2Quantity of substance
If the interposer size is increased beyond conventional limits, then more and larger IC dies can be accommodated, but the lithographic scanning complexity increases
Solution Approach 1:
The lithographic scanning process is segmented into multiple steps, with each step printing a specific image slice of the interposer. This segmentation allows the complex task of printing a large interposer to be broken down into manageable steps, each within the scanner's field size capability, while the cumulative effect achieves the desired large interposer with multiple IC dies
Solution Approach 2:
The patent performs preliminary actions by printing multiple image slices in sequence before final assembly. Each slice is prepared and printed in advance within the reticle field constraints, and then these pre-printed slices are stitched together to form the complete large interposer, simplifying the overall process by breaking it into preparatory steps
Data Source
AI summary
An embodiment of an interposer is disclosed. For this embodiment of the interposer, a first circuit portion is created responsive to a first printing region. A second circuit portion is created responsive to a second printing region. The interposer has at least one of: (a) a length dimension greater than a maximum reticle length dimension, and (b) a width dimension greater than a maximum reticle width dimension.