Semiconductor Metal Layer Structure for Solder Bleed-Out Control
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Solution Overview
Problem
The challenge in semiconductor device manufacturing lies in controlling solder bleed-out during the clip attach process, which can lead to contamination of bond pads, resulting in shorts and reduced adhesion, while also increasing chip size and reducing power efficiency and cost-effectiveness.
Innovation Solution
A semiconductor device with a metal layer structure that includes a solder area, a buffer area, and a barrier area, where the barrier area is further away from the active area than the solder and buffer areas, forming a solder reservoir to confine solder bleed-out and prevent contamination of bond pads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a clearance between the clip and additional bond pads is provided to prevent solder bleed-out contamination, then solder contamination is prevented, but chip size is increased
Solution Approach 1:
The metal layer structure is segmented into three distinct functional areas: a solder area for receiving solder, a buffer area for controlling solder flow, and a barrier area for preventing solder from reaching bond pads. This segmentation allows solder to be contained and directed within specific zones, preventing contamination without requiring increased clearance and thus avoiding chip size increase.
Solution Approach 2:
Different regions of the metal layer structure are given different properties and functions. The solder area has properties favorable for solder reception, the buffer area for solder flow control, and the barrier area for solder prevention. This local differentiation enables precise control of solder behavior in each zone, achieving contamination prevention with optimized chip size.
2Area of stationary object
If the clip size is reduced to decrease chip size, then chip size is reduced, but RDS(on) increases and power efficiency decreases
Solution Approach 1:
The metal layer structure utilizes vertical layering (z-dimension) with multiple stacked layers including the barrier base structure and metal layers at different heights. This three-dimensional arrangement allows the barrier function to be achieved without increasing the lateral footprint, enabling reduced chip size while maintaining effective solder control and electrical performance.
3Loss of energy
If solder coverage under the clip is increased to reduce RDS(on) and improve power efficiency, then electrical performance is improved, but solder bleed-out increases causing contamination
Solution Approach 1:
The buffer area acts as an intermediary zone between the solder area and the barrier area. It receives excess solder from the solder area and gradually directs it toward the barrier area, preventing sudden bleed-out and contamination. This intermediary structure allows high solder coverage for optimal electrical performance while controlling solder flow to prevent harmful bleed-out.
Data Source
AI summary
A semiconductor device and method is disclosed. The semiconductor device may include a semiconductor substrate including an active area, a metal layer structure over the active area, wherein the metal layer structure is configured to form an electrical contact, the metal layer structure including a solder area, a buffer area, and a barrier area between the solder area and the buffer area, wherein, in the barrier area, the metal layer structure is further away from the active area than in the solder area and in the buffer area, and wherein each of the solder area and the buffer area is in direct contact with the active area or with a wiring layer structure arranged between the active area and the metal layer structure.