Semiconductor Mounting Structure with Metal Protrusions for Alignment
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Solution Overview
Problem
The existing Pre-Applied method for semiconductor device manufacturing using an underfill material is inefficient, and the FC connection method with conductive paste has higher connection resistance and is prone to misalignment due to thermal stress and handling issues, especially with miniaturized semiconductor devices.
Innovation Solution
A semiconductor element mounting structure where one electrode is a protruding electrode with a solder layer and the other is an electrode pad with metal protrusions that extend into the solder layer, allowing for precise alignment and connection via pressurization and reflow, reducing misalignment and improving connection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the FC connection method with conductive paste is used, then productivity is improved, but manufacturing precision deteriorates due to misalignment caused by thermal stress and handling issues
Solution Approach 1:
The patent applies preliminary action by forming metal protrusions on the substrate electrode pad before the actual connection process. These pre-formed metal protrusions serve as alignment guides that extend into the solder layer during the connection process, ensuring precise positioning of the semiconductor element relative to the substrate even under thermal stress and handling conditions. This preliminary structural preparation prevents misalignment without requiring complex real-time control systems.
2Adaptability or versatility
If the semiconductor element is miniaturized with narrow pitch connections, then device functionality is improved, but manufacturing precision deteriorates due to increased susceptibility to misalignment
Solution Approach 1:
The patent applies local quality by concentrating the alignment function in specific localized metal protrusions at the connection points, rather than requiring uniform precision across the entire miniaturized device. These localized metal protrusions provide targeted alignment assistance exactly where needed at each narrow pitch connection point, enabling high-precision connections despite the overall miniaturization of the semiconductor element.
3Ease of manufacture
If thermal stress is applied during the connection process, then soldering is completed, but manufacturing precision deteriorates due to expansion and misalignment
Solution Approach 1:
The patent applies beforehand cushioning by designing the metal protrusions to extend into the solder layer before thermal stress is applied. This pre-established mechanical interlocking structure acts as a cushioning mechanism that compensates for thermal expansion and contraction during the soldering process. The metal protrusions maintain alignment stability throughout the thermal cycle, preventing misalignment that would otherwise occur due to differential thermal expansion between the semiconductor element and substrate.
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 structure enhances connection accuracy and reduces misalignment between semiconductor elements and substrates, particularly effective for miniaturized devices with narrow pitch connections, by ensuring stable temporary fixing during the reflow process.
Implementation Method 1
melting the solder layer of the protruding electrode by heating to connect the element electrode and the substrate electrode
Implementation Method 2
temporarily fixing the semiconductor element and the substrate in a state in which at least a portion of the one or more metal protrusions of the first electrode pad is extended into the solder layer of the first protruding electrode by pressurization
Data Source
AI summary
Provided is a semiconductor element mounting structure, including: a semiconductor element including an element electrode, and a substrate including a substrate electrode that is provided on a surface facing the semiconductor element at a position facing the element electrode, the semiconductor element and the substrate being connected via the element electrode and the substrate electrode, in which: one of the element electrode or the substrate electrode is a first protruding electrode including a solder layer at a tip portion thereof, the other of the element electrode or the substrate electrode is a first electrode pad including one or more metal protrusions on a surface thereof, the one or more metal protrusions of the first electrode pad extend into the solder layer of the first protruding electrode, and a bottom area of each of the one or more metal protrusions of the first electrode pad is 70% or less with respect to an area of the first electrode pad, or 75% or less with respect to a maximum cross-sectional area of the solder layer of the first protruding electrode.