Wafer Package Overmolding for Edge Coupler Access
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Solution Overview
Problem
Maintaining optical pathways through integrated circuit hardware during manufacturing and implementation is challenging, particularly for IC architectures with optical elements, leading to difficulties in accessing edge coupling components covered by overmolds.
Innovation Solution
The use of a sacrificial cap with a recess over the optical region prevents overmold material from obscuring the edge coupling components, allowing for an optical window to be formed by grinding and dicing processes, ensuring access to optical fibers and waveguides.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If overmold material is applied to protect and secure components, then mechanical integrity and component security are improved, but access to edge coupling components is obscured and difficult to reach
Solution Approach 1:
The patent divides the overmold into segments: a first overmold portion covering the electronic component and a second overmold portion leaving the edge coupling component exposed. This segmentation allows the overmold to provide mechanical protection where needed while maintaining access to optical components, resolving the contradiction between protection and accessibility.
Solution Approach 2:
The overmold is applied with different coverage characteristics in different regions: full coverage over the electronic component for mechanical security, and partial/no coverage over the edge coupling component for optical access. This local differentiation in overmold quality resolves the contradiction by providing strength where required while preserving operational access where needed.
2Ease of operation
If conventional techniques are used to access optical regions, then access can be achieved, but the process becomes costly, time-consuming, and imprecise
Solution Approach 1:
The patent performs preliminary action by designing the overmold structure during the initial manufacturing process to inherently provide access to optical components. The overmold is configured from the start with regions of different coverage, eliminating the need for subsequent time-consuming access operations and reducing manufacturing time while maintaining precision.
Solution Approach 2:
The patent extracts the access problem from the manufacturing process by designing the overmold to leave optical components exposed from the beginning. This removes the need for additional extraction or removal operations that would otherwise be required to access optical regions, reducing both time and cost while maintaining manufacturing precision.
3Reliability
If edge coupling components are covered by overmold, then component security is improved, but optical pathway access becomes challenging and difficult
Solution Approach 1:
The overmold is segmented into different coverage zones: one zone providing full coverage over electronic components for security and reliability, and another zone providing partial coverage or exposure at the edge where optical coupling occurs. This segmentation maintains component security while preserving optical pathway accessibility.
Solution Approach 2:
The overmold exhibits local quality variations in coverage density and transparency: opaque and thick over electronic components for security, and transparent or absent at edge coupling regions for optical access. This local differentiation resolves the contradiction by providing reliability where needed while maintaining optical detectability and accessibility where required.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method allows for efficient and precise access to optical regions within overmolded circuit packages, facilitating optical connectivity without costly, time-consuming, or imprecise conventional techniques.
Implementation Method 1
a sacrificial cap with a recess over the optical region prevents overmold material from obscuring the edge coupling components
Implementation Method 2
allowing for an optical window to be formed by grinding and dicing processes
Data Source
AI summary
The present disclosure relates to packaging techniques in connection with packaging electrical and optical components within circuit packages. For example, one or more examples described herein involve techniques for packaging an electro-photonic circuit while preserving access to a grating coupler, which may involve using a sacrificial die and/or a sacrificial cap in conjunction with a unique overmolding process. Additional examples involve techniques for preserving access to an edge coupling structure.