Semiconductor Optical Element Bonding Pad Adhesion
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Solution Overview
Problem
Existing semiconductor optical elements face challenges with low adhesion strength between resin and bonding pads, leading to detachment issues, and thick resin layers create steps that complicate connections between wiring lines and bonding pads.
Innovation Solution
A semiconductor optical element design featuring a mesa-shaped optical waveguide with a first resin layer burying the waveguide sides, a bonding pad on the resin layer, and a connecting wiring line extending on a second resin layer that covers the bonding pad's side surfaces, enhancing adhesion and facilitating connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If bonding pads are provided on resin, then adhesion strength between resin and bonding pads is low, but if bonding pads are provided on substrate without resin, then steps are formed due to great thickness of resin
Solution Approach 1:
The patent transitions from a planar bonding pad structure to a three-dimensional structure by forming side surfaces on the bonding pad that extend vertically from the resin surface. This dimensional change allows the bonding pad to maintain adequate height for wire bonding while the side surfaces provide additional bonding area and structural support, resolving the contradiction between adhesion strength and step formation.
Solution Approach 2:
The bonding pad is segmented into a base portion on the resin and side surfaces that extend upward. This segmentation allows the base portion to maintain adhesion to the resin while the side surfaces provide additional functional areas for wiring connection, effectively separating the adhesion function from the connection function.
2Ease of operation
If bonding pads are provided on substrate without resin, then steps are formed making connections difficult, but if bonding pads are provided on resin, then adhesion strength is low causing detachment
Solution Approach 1:
By forming vertical side surfaces on the bonding pad, the patent creates a three-dimensional structure that maintains adequate height for wire bonding operations while the side surfaces provide additional bonding area. This resolves the contradiction by enabling easy wiring connections through proper height while maintaining reliability through extended bonding surfaces on the side walls.
Solution Approach 2:
The bonding pad structure combines the resin base material with metal bonding pad material in a composite configuration, where the metal forms both the base portion on the resin and extends upward as side surfaces. This composite structure maintains adhesion to the resin while providing the structural integrity needed for reliable connections.
Data Source
AI summary
A semiconductor optical element is disclosed. The semiconductor optical element includes: a mesa-shaped optical waveguide formed on a substrate; a modulation electrode formed on the optical waveguide; a first resin layer that buries side surfaces of the optical waveguide; a bonding pad formed on the first resin layer; and a connecting wiring line that connects the modulation electrode and the bonding pad. In the semiconductor optical element, side surfaces of the bonding pad are partially covered with a second resin layer provided on the first resin layer, and the connecting wiring line extends on the second resin layer.