Semiconductor Module Bump Electrode Alignment and Protection
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Solution Overview
Problem
The miniaturization of semiconductor devices requires narrower electrode pitches, but conventional flip-chip mounting methods face limitations due to solder ball size and bridge formation, leading to complex manufacturing and increased costs due to the need for precise alignment of bump electrodes with semiconductor device electrodes.
Innovation Solution
A semiconductor device with a protective layer surrounding the device electrode, where the electrode surface lies on the same plane or protrudes from the protective layer, allowing for improved connection reliability even with positional displacement, and a manufacturing method involving a metallic layer for enhanced bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the pitch of electrodes is narrowed to enable further miniaturization of semiconductor devices, then the miniaturization of semiconductor devices is achieved, but the manufacturing precision and alignment accuracy become more difficult to maintain due to limitations such as solder ball size and bridge formation
Solution Approach 1:
The invention divides the electrode structure into two functional parts: the device electrode on the semiconductor substrate and the bump electrode on the mounting board. This segmentation allows the device electrode to be precisely formed during semiconductor fabrication while the bump electrode provides a larger, more tolerant target for alignment during mounting, thus resolving the contradiction between miniaturization and alignment precision.
Solution Approach 2:
The invention transitions from a planar electrode connection to a three-dimensional bump electrode structure. The bump electrode protrudes from the mounting board surface, creating a vertical dimension that increases the effective connection area and provides a larger alignment margin, thereby enabling narrower pitch without compromising alignment accuracy.
2Reliability
If the position of bump electrode and device electrode needs to be aligned more accurately to prevent displacement, then connection reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
By forming bump electrodes that protrude from the mounting board, the invention adds a vertical dimension to the connection interface. This three-dimensional structure provides a larger effective connection area and tolerance zone, improving connection reliability while reducing the stringency of alignment requirements and simplifying the manufacturing process.
Solution Approach 2:
The bump electrode structure inherently provides a cushion zone that accommodates potential positional displacements. The protruding shape creates a tolerance buffer that absorbs alignment variations, ensuring reliable connection even when perfect alignment is not achieved, thus improving reliability without increasing manufacturing complexity.
3Reliability
If the insulating layer around the electrode is present in conventional structures, then the electrode is protected and isolated, but it becomes an obstacle that prevents reliable connection when positional displacement occurs between bump electrode and device electrode
Solution Approach 1:
The invention extracts or removes the insulating layer from the critical connection interface between the bump electrode and device electrode. By forming the device electrode to protrude through or beyond the insulating layer, the connection surface is exposed and free from insulating material, ensuring reliable electrical connection even when positional displacement occurs, thus eliminating the harmful obstacle effect while maintaining the protective function of the insulating layer in other areas.
Data Source
AI summary
A semiconductor module includes a device mounting board and a semiconductor device mounted on the device mounting board. The device mounting board includes an insulating resin layer, a wiring layer provided on one main surface of the insulating resin layer, and bump electrodes, electrically connected to the wiring layer, which are protruded from the wiring layer toward the insulating resin layer. The semiconductor device has device electrodes which are disposed counter to a semiconductor substrate and the bump electrodes, respectively. The surface of a metallic layer provided on the device electrode lies on the same plane as the surface of a protective layer.