Multi-chip Package Dummy Pad Wire Short Circuit Prevention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In automotive chip packaging, bonding wires from different chips easily overlap and contact, causing short circuits and package failures due to manufacturing factors like packaging pressure and mold flow, and redesigning circuit layouts and bonding configurations is time-consuming and labor-intensive when replacing chips from different manufacturers.
Innovation Solution
A multi-chip package structure with dummy pads between input/output units and bonding pads on the first chip, allowing wires to be arranged in the same height and separate configuration, preventing overlap and contact, and enabling easy adjustment of chip designs without altering underlying layers, thus reducing skew angles and preventing short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If bonding wires are arranged in stacked configuration for multi-chip packaging, then space utilization is improved, but wires easily overlap and contact causing short circuits due to packaging pressure and mold flow
Solution Approach 1:
The patent introduces dummy pads in the horizontal plane between bonding pads and I/O units, creating a two-dimensional separation strategy. This allows wires to be routed in the same plane with adequate spacing, preventing overlap while maintaining compact vertical stacking. The dummy pads act as spatial buffers that resolve the conflict between space utilization and short circuit prevention.
Solution Approach 2:
Dummy pads serve as intermediary elements between bonding pads and I/O units. These intermediate structures provide separation distance and routing space for wires, preventing direct contact between adjacent wires from different chips. The dummy pads mediate the spatial relationship between conflicting wire paths without requiring increased package height.
2Adaptability or versatility
If circuit layout and bonding configuration are redesigned when replacing chips from different manufacturers, then compatibility is improved, but manufacturing time and labor costs increase significantly
Solution Approach 1:
The dummy pad structure serves multiple functions: it provides wire separation, defines bonding geometry, and accommodates variations in chip designs from different manufacturers. This universal structural element allows the same packaging approach to work with different chip types without requiring complete redesign of the bonding configuration, thereby maintaining adaptability while reducing redesign effort.
3Reliability
If height difference is maintained between bonding wires of upper and lower chips, then short circuit is prevented, but package height increases
Solution Approach 1:
Instead of solving the wire separation problem in the vertical dimension (height difference), the patent transitions to a horizontal dimension solution using dummy pads. This allows wires to be separated laterally in the same bonding plane, preventing short circuits while maintaining compact package height. The approach shifts the separation strategy from vertical stacking to horizontal arrangement.
Data Source
AI summary
A multi-chip package structure includes outer leads, a first chip and a second chip. The outer leads are disposed on a side of a chip bonding area of a package carrier thereof. The first chip is fixed on the chip bonding area and includes a core and a seal ring. Input/output units, and first bonding pads are disposed, in an outward order, on at a side of the core. Each first bonding pad is electrically connected to a corresponding outer lead through a first wire. Dummy pads are disposed between the input/output units and adjacent first bonding pads on the side of the core. The second chip is stacked on the core and includes second bonding pads connected to the corresponding outer leads through second wires and dummy pads, so as to prevent from short circuit caused by soldering overlap and contact between the wires.