Semiconductor Module Bonding Member Thickness Design
Solution Overview
Problem
The increasing current density in semiconductor modules leads to non-uniform current flow and thermal stress, reducing the reliability of semiconductor chips due to the direct lead bonding structure, where the conductive bonding member's thickness affects both thermal stress and the risk of wire bonding tool contact.
Innovation Solution
A semiconductor module design featuring a conductive bonding member with a thicker first bonding member for the lead electrode and a thinner second bonding member between the lead electrode and signal wires, ensuring uniform current flow and preventing wire bonding tool contact, thereby enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the conductive bonding member is increased to reduce thermal stress, then thermal stress resistance is improved, but the wire bonding tool is more likely to contact the conductive bonding member
Solution Approach 1:
The conductive bonding member has different thicknesses in different regions: a first thickness in the lead electrode bonding region and a second thickness in the signal wire bonding region. This local differentiation allows the bonding member to have sufficient thickness for thermal stress resistance where needed, while being thin enough in other regions to prevent wire bonding tool contact.
Solution Approach 2:
The conductive bonding member is divided into multiple regions with different thickness characteristics. The first bonding member region has a greater thickness to handle thermal stress, while the second bonding member region has a smaller thickness to avoid interfering with wire bonding operations. This segmentation resolves the contradiction by distributing different functional requirements to different spatial regions.
2Reliability
If the lead electrode is bonded to only a part of the surface electrode to prevent wire bonding tool contact, then wire bonding reliability is improved, but current uniformity deteriorates
Solution Approach 1:
The conductive bonding member extends beyond the lead electrode bonding region to cover additional areas of the surface electrode. This extended coverage ensures uniform current distribution across the entire bonding area, while the localized thinning in specific regions prevents wire bonding tool contact.
Solution Approach 2:
The conductive bonding member acts as an intermediary structure that simultaneously serves multiple functions: it provides a bonding interface for the lead electrode, ensures uniform current distribution, and through its differentiated thickness profile, prevents interference with wire bonding operations. This mediator structure resolves the contradiction between current uniformity and wire bonding 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
This design reduces thermal stress on the semiconductor chip, improves current uniformity, and increases the breakdown strength and heat capacity, leading to enhanced reliability and durability of the semiconductor module.
Implementation Method 1
a lead electrode bonded to a part of the surface electrode via the first bonding member
Implementation Method 2
signal wires are ultrasonically bonded to a gate electrode, an emitter electrode, a current sense electrode, a temperature sense electrode or the like on the semiconductor chip surface
Data Source
AI summary
A semiconductor chip (2) includes a surface electrode (3). A conductive bonding member (8) includes first and second bonding members (8a,8b) provided on the surface electrode (3). A lead electrode (9) is bonded to a part of the surface electrode (3) via the first bonding member (8a) and has no contact with the second bonding member (8b). A signal wire (11) is bonded to the surface electrode (3). The second bonding member (8b) is arranged between the first bonding member (8a) and the signal wire (11). A thickness of the first bonding member (8a) is larger than a thickness of the second bonding member (8b).