Self-Aligned Contact Posts for Package Assembly Alignment
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Solution Overview
Problem
The existing methods for forming contacts in device packages, such as laser cutting vias, often result in misalignment, shallow or deep cutting, leading to poor connections and increased manufacturing time, which can cause package failures due to the complexity of aligning lasers with thousands of contact pads.
Innovation Solution
The use of self-aligned contact posts formed on the contact pads before applying the package cover layer, which penetrate through the layer during processing, eliminating the need for precise laser alignment and cutting, thereby ensuring accurate communication with conductive traces and minimizing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If laser cutting vias are used to form contacts, then contacts can be formed in package layers, but misalignment and improper cutting depths occur leading to poor connections
Solution Approach 1:
The patent forms contact posts on the substrate before applying the package cover layer. This preliminary action ensures that the contact posts are already positioned and aligned with the underlying contact pads before the cover layer is applied, eliminating the need for subsequent laser drilling and alignment operations. The contact posts extend through the cover layer automatically, ensuring proper depth and alignment without requiring precise laser control.
2Productivity
If laser cutting vias are used for each contact, then contacts can be formed, but manufacturing time increases due to the large number of contacts
Solution Approach 1:
The contact posts are formed in a single batch process before the package cover layer is applied, rather than drilling each via individually. This preliminary formation of all contact posts simultaneously dramatically reduces the manufacturing cycle time, especially for packages with thousands of contacts, while ensuring each contact post is properly formed and aligned.
3Manufacturing precision
If self-aligned contact posts are formed before applying cover layer, then alignment accuracy improves, but additional process steps are required
Solution Approach 1:
The contact posts are formed on the substrate before the package cover layer is applied. This timing allows the contact posts to be self-aligned with the underlying contact pads through the substrate's natural geometry, eliminating the need for complex alignment procedures. The contact posts then automatically penetrate the cover layer at the correct positions, simplifying the overall process despite the additional initial formation step.
Solution Approach 2:
The contact posts are designed to automatically align with and penetrate the package cover layer without requiring external alignment mechanisms or complex positioning systems. The substrate's structure and the contact post geometry work together to ensure proper alignment, allowing the system to self-align during the manufacturing process.
Data Source
AI summary
A package assembly includes a substrate extending from a first substrate end to a second substrate end. A plurality of conductive traces extend along the substrate. A plurality of contacts are coupled with the respective conductive traces of the plurality of conductive traces. Each of the contacts of the plurality of contacts includes a contact pad coupled with a respective conductive trace of the plurality of conductive traces, and a contact post coupled with the contact pad, the contact post extends from the contact pad. A package cover layer is coupled over the plurality of contact posts. The plurality of contact posts are configured to penetrate the package cover layer and extend to a raised location above the package cover layer.