Adhesive Patch With Inwardly Sloped Side Surfaces
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Solution Overview
Problem
The challenge is to form a semiconductor device with a sealing body that does not crack, especially when using the electrolysis plating method for external terminals, which can lead to moisture intrusion and reduced reliability due to protruding insulating resin layers during the peeling process.
Innovation Solution
A manufacturing method involving a semiconductor wafer with an adhesive patch bonded to its back surface, which is then fixed to a metallic mother substrate, ensuring the adhesive patch does not protrude from the semiconductor chip's side surface, and the sealing body is formed without cracks by controlling heat treatment temperatures and pressures to maintain the adhesive patch's shape and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the back surface of the semiconductor chip is exposed from the sealing body to eliminate the die pad and reduce device size, then the device size and thickness are reduced, but cracks are easily generated in the semiconductor chip due to applied loads and moisture can enter from the interface
Solution Approach 1:
An insulating resin layer is introduced as an intermediary substance between the semiconductor chip and the sealing body. This layer covers the back surface of the chip, preventing direct exposure while allowing the die pad to be eliminated. The insulating resin layer acts as a protective mediator that prevents crack propagation and moisture intrusion at the chip-sealing body interface, thus maintaining reliability while enabling size reduction.
2Reliability
If an insulating resin layer is formed by coating on the back surface of the semiconductor chip to protect it, then the back surface is protected from cracks and moisture, but the insulating resin layer may protrude from the side surface during the peeling process when using electrolysis plating method
Solution Approach 1:
The insulating resin layer is formed by coating on the back surface of the semiconductor chip before the electrolysis plating process. This preliminary formation ensures proper adhesion and positioning of the resin layer, preventing it from protruding during subsequent peeling operations. The advance preparation of the resin layer with appropriate thickness and adhesion properties eliminates manufacturing precision issues that would otherwise occur during the plating and peeling processes.
3Ease of manufacture
If the adhesive patch side surfaces are made vertical to simplify manufacturing, then the manufacturing process is simplified, but the adhesive patch may protrude from the semiconductor chip side surface during peeling
Solution Approach 1:
Instead of using vertical side surfaces for the adhesive patch, the patent employs inwardly sloped side surfaces. This asymmetric geometry prevents the adhesive patch from protruding during the peeling process while maintaining ease of manufacture. The sloped configuration naturally guides the adhesive material inward, ensuring proper positioning and preventing defects without requiring complex manufacturing steps.
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 method prevents cracks in the sealing body, enhances the reliability of the semiconductor device by preventing moisture intrusion, and allows for further reduction in size and thickness while maintaining device reliability.
Implementation Method 1
bonding a film-like adhesive sheet to the second principal surface of the semiconductor wafer in a state where heat has been applied to the semiconductor wafer
Implementation Method 2
applying a second temperature higher than the first temperature to the semiconductor wafer having the adhesive sheet bonded thereto
Implementation Method 3
forming a sealing body by sealing with resin the semiconductor chip, the adhesive patch, and the upper surface of the mother substrate
Data Source
AI summary
A semiconductor device has an external terminal formed through the use of an electrolysis plating method. A front surface of a semiconductor wafer is placed over a front surface of a first support heated to a first temperature. An adhesive sheet is then bonded to a back surface of the semiconductor wafer, after which the semiconductor wafer is subjected to heat treatment at a second temperature higher than the first temperature. After the semiconductor wafer and the adhesive sheet are cut along cutting regions, a plurality of semiconductor chips each having an adhesive patch bonded thereto are obtained. A mother substrate is placed over a front surface of a second support heated to a third temperature and the semiconductor chips are fixed to an upper surface of the mother substrate via the adhesive patch.