Die Bonding Agent Viscosity Control for Semiconductor Reliability
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Solution Overview
Problem
Die bonding agents with high adhesion strength often suffer from delamination at the interface with substrates due to thermal expansion coefficient mismatches, leading to stress and cracks in semiconductor devices, and struggle to form fillets of specific size and shape required for downsizing and higher integration.
Innovation Solution
A die bonding agent comprising epoxy resin, a curing agent, and inorganic filler, with specific rheological properties, including a viscosity ratio of 1.5 to 4 at room temperature to 50°C and 0.5 to 1.5 at curing temperature, which allows for controlled fillet formation and reduced stress, enabling downsizing and high integration of semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a die bonding agent with high adhesion strength is used, then bonding strength is improved, but delamination occurs at the interface between the die bonding agent and substrate due to thermal expansion coefficient mismatch
Solution Approach 1:
The die bonding agent uses a composite formulation combining epoxy resin with specific inorganic fillers (such as silica or alumina) to create a material that maintains both high adhesion strength and thermal expansion compatibility. The inorganic fillers help match the thermal expansion coefficient with the substrate, preventing delamination while preserving bonding strength.
Solution Approach 2:
The invention modifies the rheological parameters of the die bonding agent by controlling viscosity ratios at different temperatures. The viscosity ratio at room temperature to 50°C is maintained at 1.5-4, and at curing temperature the ratio is 0.5-1.5, which optimizes both adhesion and stress distribution to prevent interface delamination.
2Reliability
If a die bonding agent with large fillet size is used, then bonding reliability is improved, but device downsizing and higher integration are prevented
Solution Approach 1:
The invention precisely controls the rheological parameters of the die bonding agent, specifically the viscosity ratio at different temperatures. By maintaining viscosity ratio of 1.5-4 at room temperature to 50°C and 0.5-1.5 at curing temperature, the fillet forms with optimal size and shape that ensures bonding reliability while enabling device downsizing.
3Shape
If a die bonding agent with high viscosity is used, then fillet shape control is improved, but fillet formation and stress distribution are compromised
Solution Approach 1:
The invention uses temperature-dependent viscosity control through specific rheological parameters. The viscosity ratio at room temperature to 50°C is 1.5-4, allowing good shape control during application, while the viscosity ratio at curing temperature is 0.5-1.5, ensuring proper fillet formation and stress distribution during curing.
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
The die bonding agent effectively prevents delamination and achieves the desired fillet shape and size, enhancing the reliability and integration of semiconductor devices by managing thermal stress and fluidity during bonding and curing processes.
Implementation Method 1
the die bonding agent having a viscosity ratio, V1/V2, ranging (i) from 1.5 to 4 at a temperature of from room temperature to 50° C., and (ii) from 0.5 to less than 1.5 at a temperature at which the die bonding agent hardens
Implementation Method 2
a die bonding agent comprising (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler
Implementation Method 3
in a device comprising a chip encapsulated with an encapsulant having liner expansion coefficient different from that of a die bonding agent, a large stress is generated at an interface between the die bonding agent and the encapsulant
Data Source
AI summary
A die bonding agent comprising (A) an epoxy resin, (B) a curing agent, and (C) an inorganic filler, the die bonding agent having a viscosity ratio, V1/V2, ranging(i) from 1.5 to 4 at a temperature of from room temperature to 50° C., and(ii) from 0.5 to less than 1.5 at a temperature at which the die bonding agent hardens in 0.5 hour to 1.5 hours, the viscosities being measured in 10 minutes after the die bonding agent is placed on a sample stage of a Brook Field viscometer, wherein V1 is a viscosity measured by stirring 0.5 ml of the die bonding agent with a No. 51 spindle at 0.5 rpm and V2 is a viscosity measured by stirring 0.5 ml of the die bonding agent with a No. 51 spindle at 5 rpm in the Brook Field viscometer.