Semiconductor Pad Projections for Wire Bonding Reliability
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Solution Overview
Problem
Existing semiconductor and liquid discharge head technologies face instability and disconnection issues due to small contact areas between bonding balls and pads, especially when the capillary is displaced from its desired position, leading to unreliable electrical connections.
Innovation Solution
The implementation of a semiconductor element with an insulation layer featuring projections that support pad portions, preventing the bonding ball from contacting the pad when displaced, and a liquid discharge head design with a through hole and sealing material to enhance electrical connection reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire bonding is performed without projections on the insulation layer, then the manufacturing process is simpler, but the electrical connection reliability deteriorates when the capillary is displaced
Solution Approach 1:
The insulation layer is designed with projections that extend in the vertical dimension, creating a three-dimensional structure. This dimensional change allows the pad portion to be elevated above the main surface, ensuring that even when the capillary is displaced horizontally, the bonding ball can still make contact with the pad through the projection structure, thereby maintaining electrical connection reliability.
Solution Approach 2:
The projections are pre-formed on the insulation layer before wire bonding occurs. This preliminary structuring of the insulation layer with elevated pad portions prepares the connection interface in advance, so that when bonding takes place, the pad is already positioned at an optimal height and location to accommodate potential capillary displacement, ensuring reliable connection without requiring real-time adjustment.
2Reliability
If the pad portion extends beyond the projection upper surface, then the electrical connection area is larger, but the risk of inadequate contact increases when capillary is displaced
Solution Approach 1:
The pad portion is configured with non-uniform extension relative to the projection, creating different functional zones. The pad extends beyond the projection upper surface in specific directions to provide adequate contact area, while maintaining precise positioning control in other areas. This local variation in pad geometry optimizes both connection reliability and positioning precision by tailoring the contact characteristics to specific bonding requirements.
Data Source
AI summary
A semiconductor element includes an insulation layer and a pad portion for electrical connection to an external portion by wire bonding. The insulation layer includes a plurality of projections projecting from a main surface of the insulation layer. The pad portion is disposed on an upper surface of each of the projections without extending beyond the upper surface of the projection on which the pad portion is formed.