Semiconductor Package Adhesion via Polyimide Front Surface Layer
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Solution Overview
Problem
Semiconductor devices with different-sized chips face adherence issues between the chips and the sealing resin, leading to water ingress and expansion during reflow processes, causing cracks and reducing humidity resistance and reliability.
Innovation Solution
A semiconductor device design that includes a wiring board, semiconductor chips with surface films, a supporting plate with a front surface layer of the same material as the surface films, and a spacer, all covered by a sealing resin that contacts the surface films and the front surface layer, enhancing adherence and preventing water ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different-sized semiconductor chips are stacked and packaged with a supporting plate, then device integration is achieved, but adherence between the chip/supporing plate and sealing resin deteriorates
Solution Approach 1:
A front surface layer made of polyimide is introduced as an intermediary between the supporting plate and the sealing resin. This front surface layer acts as a mediator that improves the adherence between the supporting plate and the sealing resin, preventing water ingress while maintaining the stacked package structure with different-sized chips.
Solution Approach 2:
The supporting plate is constructed with a composite structure consisting of a base material (such as ceramic or metal) and a front surface layer made of polyimide. This composite material approach combines the mechanical strength of the base material with the adhesive properties of the polyimide layer, achieving both structural integrity and good adherence to the sealing resin.
2Ease of manufacture
If poor adherence exists between the chip/supporing plate and sealing resin, then manufacturing is simpler, but water ingress occurs causing cracks and reducing humidity resistance
Solution Approach 1:
The polyimide front surface layer serves as a protective intermediary that prevents water from reaching the interface between the supporting plate and the sealing resin. This intermediary layer maintains manufacturing simplicity while effectively blocking water ingress that would otherwise cause cracks and reliability issues.
3Temperature
If water enters the interface and expands during reflow process, then thermal processing is simpler, but cracks appear and reliability reduces
Solution Approach 1:
The polyimide front surface layer is provided in advance as a protective barrier before the reflow process. This layer cushions against the expansion of water during thermal processing by preventing water from reaching the critical interfaces, thereby avoiding crack formation while allowing standard reflow processing to proceed.
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
Improves the adherence of the sealing resin, preventing cracks and enhancing the humidity resistance and reliability of the semiconductor device by ensuring good contact between the resin and the surface films, even when different materials are used.
Implementation Method 1
a front surface layer provided on the first surface and formed of the same material as the second surface film... a sealing resin that covers the second semiconductor chip and the supporting plate and that contacts the second surface film and the front surface layer
Data Source
AI summary
A semiconductor device includes a wiring board, a first semiconductor chip fixed to the wiring board and having a first surface film, a second semiconductor chip having a second surface film and positioned such that the first semiconductor chip is between the second semiconductor chip and the wiring board, a supporting plate between the first and second semiconductor chips, the supporting plate having a first surface and a second surface located on the side opposite to the first surface, the second surface facing the first semiconductor chip, and supporting the second semiconductor chip, a front surface layer on the first surface and formed of the same material as the second surface film, a spacer between the wiring board and the supporting plate, and a sealing resin that covers the second semiconductor chip and the supporting plate and contacts the second surface film and the front surface layer.