Semiconductor Element Bonding Body With Concave Portion
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Solution Overview
Problem
Existing semiconductor devices face challenges with heat dissipation due to thermal resistance from bonding materials and have complex bonding structures that hinder mass producibility and stability, while solid-phase diffusion bonding requires precise surface smoothing to prevent positional shifts during automated bonding.
Innovation Solution
A semiconductor element bonding body with a concave portion on a metal mount member, where the concave portion has a specific level difference and flatness, allowing direct solid-phase diffusion bonding between the substrate and semiconductor element, enhancing heat dissipation and preventing positional shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a bonding material is used to bond the semiconductor element to the substrate, then the bonding process is simplified, but thermal resistance increases and heat dissipation properties deteriorate
Solution Approach 1:
The invention extracts and removes the bonding material from the bonding interface between the semiconductor element and substrate. By forming a concave portion in the substrate that directly receives and bonds the semiconductor element, the bonding material is eliminated from the heat conduction path, thereby resolving the contradiction between ease of manufacture and heat dissipation efficiency.
Solution Approach 2:
The concave portion is formed in the substrate before the semiconductor element is mounted. This preliminary action creates a precise receptacle that guides the semiconductor element into direct contact with the substrate, enabling bonding without intermediate materials while maintaining manufacturing simplicity.
2Loss of energy
If solid-phase diffusion bonding is used to directly bond the semiconductor element to the substrate, then heat dissipation properties improve, but the bonding surface requires precise smoothing by polishing which increases device complexity
Solution Approach 1:
The concave portion is formed in the substrate before mounting the semiconductor element. This preliminary formation of the concave portion with predetermined flatness reduces the requirement for high-precision polishing of the entire bonding surface, thereby maintaining direct bonding heat dissipation advantages while reducing overall process complexity.
Solution Approach 2:
Instead of requiring the entire substrate surface to be highly polished, only the bottom surface of the concave portion needs to achieve the required flatness (λ/8.7 μm or more and λ/1.2 μm or less). This local quality approach concentrates the precision requirement to a small area, reducing overall device complexity while maintaining effective heat dissipation.
3Manufacturing precision
If the bonding surface is smoothed by polishing to enable solid-phase diffusion bonding, then positional shift during automated bonding is reduced, but manufacturing time and cost increase
Solution Approach 1:
The concave portion is formed in advance in the substrate, creating a mechanical guide structure. When the semiconductor element is placed in the concave portion, its position is automatically determined by the geometry of the concave portion, eliminating the need for time-consuming polishing operations while maintaining high positional accuracy during automated bonding.
Solution Approach 2:
The invention replaces the mechanical polishing process with a geometric constraint system. The concave portion's shape provides mechanical guidance that automatically positions the semiconductor element, substituting the time-intensive polishing operation with a faster geometric fitting approach that maintains precision.
4Strength
If a complex bonding layer structure is used to bond the semiconductor element to the substrate, then bonding strength improves, but management of bonding temperature, time, and layer thickness becomes laborious reducing mass producibility
Solution Approach 1:
The invention extracts and eliminates the complex multi-layer bonding structure from the bonding interface. By using direct solid-phase diffusion bonding between the semiconductor element and the substrate through the concave portion, the complex bonding layer structure is removed, simplifying parameter management (temperature, time, thickness) while maintaining bonding strength.
Solution Approach 2:
The bonding interface is segmented into distinct functional zones: the concave portion in the substrate providing mechanical retention and positioning, and the direct bonding interface for heat dissipation. This segmentation eliminates the need for intermediate bonding layers, simplifying the overall bonding structure while maintaining both strength and mass producibility.
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 solution improves heat dissipation properties and prevents positional shifts of the semiconductor element, while simplifying the bonding process and reducing thermal resistance, thus enhancing manufacturing efficiency and bonding quality.
Implementation Method 1
solid-phase diffusion bonding is superior, in which the semiconductor element is bonded directly to a substrate without a bonding material interposed between the two
Data Source
AI summary
A semiconductor element bonding body including: a substrate, in which a concave portion is formed; and a semiconductor element placed in the concave portion to be mounted to the substrate. A portion of the substrate in which the concave portion is formed is made of Cu. The concave portion has a perimeter portion in which a level difference is formed, and the level difference has a height d of 20 μm or more and less than 50 μm. The concave portion has a bottom surface having a flatness degree of λ/8.7 μm or more and λ/1.2 μm or less when a wavelength λ of a laser is 632.8 nm. A metal film is formed on the semiconductor element, and the bottom surface of the concave portion and the metal film are bonded directly to each other.