Semiconductor Underfill Anchors via Insulating Layer Openings
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Solution Overview
Problem
Conventional flip-chip solder joints and underfill materials in semiconductor chip packaging are prone to delamination due to mechanical stresses from coefficient of thermal expansion mismatches and warping, leading to potential device failure.
Innovation Solution
A method involving the application of an insulating layer on a semiconductor chip with strategically formed openings that do not extend through the entire layer, allowing underfill material projections to form mechanical linkages and inhibit delamination, while also serving as an etch mask to protect underlying structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If openings are formed in the polyimide layer to serve as anchor spots for underfill material, then underfill delamination is inhibited, but the polyimide layer becomes unsuitable as an etch mask
Solution Approach 1:
The patent divides the opening structure into two distinct types: first openings that do not extend through the polyimide layer (serving as etch mask anchors) and second openings that extend through the polyimide layer (serving as underfill anchors). This segmentation allows each type of opening to fulfill its specific function without compromising the other, resolving the contradiction between maintaining etch mask functionality and providing underfill anchoring.
Solution Approach 2:
The patent applies different opening characteristics at different locations within the polyimide layer. By creating shallower first openings in certain regions and deeper second openings in other regions, the structure achieves local differentiation that simultaneously preserves etch mask integrity where needed and provides underfill anchoring where required.
2Stress or pressure
If underfill material is placed between chip and package substrate to reduce CIE mismatch effects, then thermal stress resistance is improved, but delamination can still occur under severe bending moments
Solution Approach 1:
The patent creates anchor spots in the polyimide layer before underfill material is applied. These pre-formed first and second openings provide predetermined anchoring locations that guide underfill material placement, ensuring strong mechanical interlocking is established in advance to resist subsequent thermal stresses and bending moments.
Solution Approach 2:
The patent creates a composite structure where the underfill material interacts with both the polyimide layer (through second openings extending through the polyimide) and the underlying conductor structures (through first openings that do not extend through the polyimide). This multi-layer composite anchoring system enhances overall bonding stability and delamination resistance.
Data Source
AI summary
Various semiconductor chips and methods of making the same are disclosed. In one aspect, a method of manufacturing is provided that includes forming a first opening in an insulating layer applied to a side of a semiconductor chip. The first opening does not extend through to the side. A second opening is formed in the insulating layer that exposes a portion of the side.