Semiconductor Backside Wiring Insulation Crack Prevention
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Solution Overview
Problem
Conventional BGA type semiconductor devices experience damage to the second insulation film during handling, leading to cracks and subsequent corrosion of pad electrodes and the semiconductor substrate, reducing the reliability of the device.
Innovation Solution
A semiconductor device manufacturing method involving the formation of a support body on the semiconductor substrate, etching an opening from the back surface, applying a second insulation film and a protection layer to cover the opening's sidewalls and bottom, and forming a wiring layer that extends into the opening to contact the pad electrode, thereby preventing damage and corrosion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a support body is formed on the front surface of the semiconductor substrate, then the mechanical strength is improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The support body is formed on the front surface of the semiconductor substrate before the opening formation process. This preliminary action reinforces the substrate structure in advance, preventing distortion and crack propagation during subsequent handling and processing steps, thereby resolving the contradiction between improving mechanical strength and maintaining manufacturing simplicity
2Reliability
If the second insulation film is formed on the back surface, then the electrical insulation is improved, but the film becomes vulnerable to cracks during handling
Solution Approach 1:
The protection layer is formed covering the boundary between the sidewall and bottom of the opening before any handling or subsequent processing occurs. This protection layer acts as a cushioning barrier that absorbs stress and prevents crack propagation in the second insulation film during handling, while maintaining its electrical insulation function
Solution Approach 2:
The protection layer is formed using a material that combines mechanical strength properties with compatibility to the second insulation film. This composite structure integrates the protective function with the insulating function, creating a multi-functional layer that prevents cracks while maintaining electrical insulation
3Ease of manufacture
If the opening is formed by etching from the back surface, then the wiring connection is improved, but cracks occur in the insulation film at the opening boundary
Solution Approach 1:
The protection layer is selectively formed only at the critical boundary region between the sidewall and bottom of the opening, rather than covering the entire surface. This localized protection precisely addresses the area most susceptible to cracking during etching and handling, maintaining opening integrity for proper wiring connection while avoiding unnecessary process complexity
Data Source
AI summary
The invention is directed to improvement of reliability of a chip size package type semiconductor device in a manufacturing method thereof. A support body is formed on a front surface of a semiconductor substrate with a first insulation film therebetween. Then, a part of the semiconductor substrate is selectively etched from its back surface to form an opening, and then a second insulation film is formed on the back surface. Next, the first insulation film and the second insulation film at a bottom of the opening are selectively etched, to expose pad electrodes at the bottom of the opening. Then, a third resist layer is selectively formed on a second insulation film at boundaries between sidewalls and the bottom of the opening on the back surface of the semiconductor substrate. Furthermore, a wiring layer electrically connected with the pad electrodes at the bottom of the opening and extending onto the back surface of the semiconductor substrate is selectively formed corresponding to a predetermined pattern.