Thin Semiconductor Circuit Detachment via Solder Support

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Solution Overview

Problem

Thin semiconductor circuits with low intrinsic stability face damage risks during detachment from their silicon wafer base, especially when transferred to chip cards, due to existing complex and costly methods that may result in waste and mechanical instability.

Innovation Solution

Attaching the semiconductor circuit to a support substrate using soldering operations with gold terminals, providing mechanical stability and using a polymer layer for protection, and then removing the base through grinding and etching, while ensuring no electrical short-circuits occur.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If adhesive films are used to detach chips from the base, then the chips can be released at the desired site, but the films are difficult to handle and very expensive

Engineering Contradiction:

Improvechip detachment reliabilityVSAvoidadhesive film handling complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the adhesive film from the process entirely and replaces it with a soldering-based attachment method. The chip is soldered directly to the support substrate using its existing terminals, eliminating the need for separate adhesive films and their associated handling complexities.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention introduces solder as an intermediary material between the chip terminals and the support substrate. This solder layer provides both mechanical attachment and electrical connection, replacing the complex adhesive film system with a simpler, more reliable soldering process.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a separation layer is removed to detach the chip, then the chip can be separated from the substrate, but the process requires high outlay in terms of process technology and may cause damage

Engineering Contradiction:

Improvechip separation reliabilityVSAvoidprocess technology complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of removing a separation layer to detach the chip, the invention inverts the approach by soldering the chip to the support substrate. This reverse engineering approach uses the chip's own terminals as attachment points, eliminating the need for complex separation layer removal processes.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention enables the chip to attach itself to the support substrate using its existing terminals for soldering. The chip's terminals, which are already present for electrical contacting, serve dual purposes: electrical connection during operation and mechanical attachment during transfer, eliminating the need for additional separation layers.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If the chip is detached without additional support, then the detachment process is simpler, but the chip has low intrinsic stability and may break under its own weight

Engineering Contradiction:

Improvedetachment process simplicityVSAvoidchip mechanical stability

Core Design Contradiction:

Ease of operationVSStrength

Solution Approach 1:

The invention performs preliminary action by soldering the chip to the support substrate before the actual detachment and transfer process. This pre-attachment provides the mechanical stability needed throughout subsequent handling operations, preventing the thin chip from breaking under its own weight or during manipulation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention creates a composite structure by bonding the chip to the support substrate through soldering. This composite assembly combines the fragile chip with the mechanically strong support substrate, providing the necessary structural stability while maintaining the chip's electrical functionality.

Inventive Principle:

Principle #40Composite materials

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

Enables the safe and damage-free transfer of thin semiconductor circuits onto chip cards, maintaining mechanical stability and preventing waste, with the method being applicable to circuits up to 20 μm thickness and potentially thicker ones.

Implementation Method 1

the usual melting temperature of the soldering tin of 218° C. is sufficiently exceeded

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

use is made of the electrical terminals of the semiconductor circuit which have to be provided in any case in order to supply electrical power to the semiconductor circuit during subsequent operation. The soldering operation preferably takes place at a temperature of 250° C.

Methodology Applied

Scientific EffectSoldering: Soldering

Data Source

PatentUS8338228B2Method of detaching a thin semiconductor circuit from its base

Publication Date: 2012.12.25 UNITED MICROELECTRONICS CORP

AI summary

In order to provide a method of detaching a thin semiconductor circuit (1) from its base (2), wherein the semiconductor circuit (1) is provided with terminals (3) for electrical contacting, in particular with gold contacts, by means of which method thin semiconductor circuits (1) can also be mounted without damage for example directly on a chip card, it is proposed that a layer of soldering tin (6) is applied to a support substrate (4), the support substrate (4) is soldered to the electrical terminals (3) and the base (2) of the semiconductor circuit (1) is removed.