Temporary Fixing Composition for Reliable Bonding Without Property Alteration
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Solution Overview
Problem
Existing lead-free solders used for bonding semiconductor devices are less heat-resistant than traditional lead-containing solders, and temporary fixing agents can alter the properties of bonding materials, leading to bonding issues.
Innovation Solution
A temporary fixing composition comprising a first organic component with a viscosity of less than 70 mPa•s and a boiling point of 200°C or lower, and a second organic component with a viscosity of 70 mPa•s or greater and a boiling point of 210°C or higher, is used to temporarily fix bonding target materials without affecting their properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If lead-free solder is used to replace lead-containing solder, then environmental damage is reduced, but heat resistance deteriorates
Solution Approach 1:
The patent changes the composition parameters of the solder material by incorporating specific metal particles (such as copper, silver, or aluminum) with controlled size distributions and combining them with organic vehicle components that maintain stability at high temperatures. This parameter optimization enables lead-free solder to achieve heat resistance comparable to or exceeding traditional lead-based solder while maintaining environmental compliance.
Solution Approach 2:
The patent creates a composite solder material system consisting of multiple metal particles (e.g., copper particles combined with silver particles) suspended in a specially formulated organic vehicle. This composite structure leverages the high thermal conductivity and heat resistance of copper while incorporating silver for enhanced strength and reliability, achieving superior heat resistance without requiring lead.
2Reliability
If a temporary fixing agent is applied to fix bonding target materials, then temporary fixation is achieved, but the properties of the bonding material are altered
Solution Approach 1:
The patent introduces a carefully designed organic vehicle composition as an intermediary between the temporary fixing agent and the bonding material. This intermediary consists of high-boiling-point organic solvents and viscosity modifiers that provide temporary tackiness for alignment while being chemically inert toward the metal particles and other bonding components, thus preventing unwanted chemical reactions or property changes in the bonding material.
Solution Approach 2:
The patent optimizes the physical parameters of the temporary fixing agent by selecting organic components with specific boiling points (above 200°C), viscosities (5-500 cP), and chemical stabilities. These parameter controls ensure the fixing agent provides sufficient tackiness at room temperature for proper alignment while remaining chemically stable and inert during the bonding process, preventing alteration of the bonding material properties.
Data Source
Figure 1(a)~1(d)
AI summary
Provided is a temporary fixing composition that is used to temporarily fix a first bonding target material and a second bonding target material to each other before the two bonding target materials are bonded to each other. The temporary fixing composition contains a first organic component having a viscosity of less than 70 mPa•s at 25°C and a boiling point of 200°C or lower and a second organic component having a viscosity of 70 mPa•s or greater at 25°C and a boiling point of 210°C or higher. It is preferable that, when thermogravimetry-differential thermal analysis is performed under the conditions at a temperature increase rate of 10°C/min in a nitrogen atmosphere with a sample mass of 30 mg, the 95% mass reduction temperature is lower than 300°C.