Auxiliary Member Thermal Expansion Corrects Wiring Substrate Warp
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Solution Overview
Problem
Thinner wiring substrates in semiconductor devices experience excessive warp during heating processes, leading to unreliable electrical connections when mounted on motherboards due to increased allowable warp values and narrower pitch of external connection terminals.
Innovation Solution
Incorporating an auxiliary member with a higher coefficient of thermal expansion than the semiconductor chip and wiring substrate, fixed via an adhesive layer, which protrudes over the underfill resin and is sealed with a thermosetting resin to correct warp issues by expanding and contracting differently than the chip and substrate, thereby maintaining reliable electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the wiring substrate is made thinner to achieve miniaturization, then the device size is reduced, but the warp of the wiring substrate during heating process exceeds allowable values
Solution Approach 1:
The patent introduces an auxiliary member with a coefficient of thermal expansion different from that of the wiring substrate and semiconductor chip. This parameter change in material properties allows the auxiliary member to expand and contract at different rates during heating and cooling processes, generating counteracting forces that suppress warp in the thinned wiring substrate while maintaining miniaturization benefits
Solution Approach 2:
The patent creates a composite structure by bonding the auxiliary member to the semiconductor chip using an adhesive layer. This composite construction combines materials with different thermal expansion characteristics, where the auxiliary member compensates for substrate warp through its contrasting thermal response, thereby stabilizing the overall device structure during temperature variations
2Volume of moving object
If the wiring substrate is made thinner, then miniaturization is achieved, but the reliability of electrical connection becomes insufficient due to excessive warp
Solution Approach 1:
By selecting an auxiliary member with a specific coefficient of thermal expansion parameter that differs from the wiring substrate, the patent enables the auxiliary member to counteract substrate warp during heating processes. This parameter optimization ensures that electrical connections remain reliable even when the wiring substrate is thinned for miniaturization
Solution Approach 2:
The auxiliary member is pre-installed on the semiconductor chip before final assembly, positioned to provide preliminary counter-action against potential warp. This preemptive measure ensures that when the device undergoes heating during operation or mounting, the auxiliary member is already in place to suppress warp and maintain connection reliability
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 auxiliary member effectively corrects warp issues by expanding and contracting in opposite directions to the chip and substrate, ensuring the semiconductor device remains within allowable warp limits, thus ensuring reliable electrical connections to the motherboard.
Implementation Method 1
respective coefficients of thermal expansion of the auxiliary member and the adhesive layer are larger than a coefficient of thermal expansion of the semiconductor chip
Data Source
AI summary
A semiconductor device includes a wiring substrate, a semiconductor chip whose connection terminal is connected to the wiring substrate, an underfill resin formed from a clearance between the wiring substrate and the semiconductor chip to a periphery area of the semiconductor chip, wherein the underfill resin in the periphery area is formed at a same height as an upper surface of the semiconductor chip, an auxiliary member fixed on the semiconductor chip by an adhesive layer, and including a protruding portion which protrudes to an outside from the semiconductor chip, and the protruding portion arranged at least on the underfill resin via the adhesive layer, and a sealing resin sealing the underfill resin and at least side faces of the auxiliary member, wherein respective coefficients of thermal expansion of the auxiliary member and the adhesive layer are larger than a coefficient of thermal expansion of the semiconductor chip.