Recessed Metal Layer Bonding for Semiconductor Devices
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Solution Overview
Problem
Existing semiconductor device manufacturing methods face challenges with low bond strength between insulated circuit boards, external terminals, and printed circuit boards, leading to increased manufacturing costs and device size due to the need for high-precision machining and separate soldering processes, which can cause semiconductor chips to shift during assembly.
Innovation Solution
A semiconductor device design featuring a recessed metal layer on the insulated circuit board with a rod-shaped external terminal inserted into the recess, supported by a printed circuit board, and connected using a bonding material within the recess to enhance bond strength and manufacturability, while minimizing solder spread and reducing the overall device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If solder is applied around the outer peripheral surface of the bottom end of the external terminal to improve bond strength, then bond strength increases, but the wetting and spreading region enlarges causing solder to contact nearby semiconductor chip bonding solder, potentially shifting the semiconductor chip position
Solution Approach 1:
The patent applies local quality by creating a recess structure in the metal layer with different dimensional characteristics at different locations. The recess has a smaller cross-sectional area at the bottom compared to the top, allowing solder to be confined in a localized region around the external terminal bottom end. This prevents solder from spreading to adjacent areas while maintaining sufficient bond strength through the recess geometry.
2Reliability
If more area is allocated for the metal layer to prevent solder wetting and spreading region from contacting semiconductor chip bonding solder, then chip position stability improves, but the overall size of the semiconductor device increases
Solution Approach 1:
Instead of increasing the overall metal layer area, the patent employs local quality by forming recesses with controlled cross-sectional areas. The recess structure confines solder wetting and spreading regions to specific localized areas, preventing contact between external terminal solder and semiconductor chip bonding solder without requiring additional metal layer area. This maintains chip position stability while avoiding device size increase.
3Reliability
If high-precision machining processes are used to form holes in the metal layer or shape external terminal ends to achieve reliable bonding, then bond reliability improves, but manufacturing costs increase
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the metal layer structure. Instead of requiring high-precision machining of holes or terminal shapes, the invention forms recesses with specific depth and cross-sectional area ratios. These parameter-controlled recesses enable reliable bonding through simplified processes such as casting or pressing, reducing manufacturing complexity and cost while maintaining bond reliability.
4Reliability
If separate processes are used for providing solder between external terminals and printed circuit board, then connection reliability improves, but assembling process complexity increases
Solution Approach 1:
The patent merges multiple bonding functions into a single integrated structure. The recess in the metal layer serves multiple purposes: it provides mechanical support for the external terminal, confines the solder bonding material, and creates a reliable electrical connection pathway. This unified approach eliminates the need for separate soldering processes between external terminals and the printed circuit board, reducing assembling process complexity while maintaining connection reliability.
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
This design significantly increases bond strength between the circuit boards and terminals, reduces manufacturing complexity and costs, and allows for miniaturization of the semiconductor device by controlling the amount of bonding material and optimizing the recess shape.
Implementation Method 1
a first bonding material that is arranged inside the recess and conductively connects together the bottom end of the external terminal and the metal layer
Data Source
AI summary
A semiconductor device includes: an insulated circuit board including metal layers having recesses, and an insulating board having an upper surface on which the metal layers are arranged; external terminals having bottom ends with a width narrower than the width of openings of the recesses, these bottom ends being inserted into the recesses; a printed circuit board that directly supports the external terminals; and first bonding material that is arranged inside the recesses and respectively conductively connects the bottom ends of the external terminals to the metal layers.