Semiconductor Pad Layout for Uniform Heat Distribution
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Solution Overview
Problem
The flip-chip mounting method for semiconductor devices faces issues with bonding reliability due to non-uniform heat distribution among bump electrodes, leading to defects, especially at array ends and gaps, and the introduction of dummy bumps can cause heat transmission problems and short-circuits.
Innovation Solution
The implementation of a semiconductor device design with a specific layout of pads and conductive members, where first and second pads have distinct electrical currents, and dummy pads or bumps are strategically placed to maintain heat retention and prevent short-circuits, ensuring uniform heat distribution and reliable bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dummy bumps are introduced to retain heat at array ends and gaps, then bonding reliability is improved, but heat transmission problems and short-circuits occur
Solution Approach 1:
The patent extracts the heat retention function from dummy bumps and transfers it to the existing pad structure. By designing pads with extended regions at array ends and gaps, the pad itself serves as a heat retaining wall, eliminating the need for separate dummy bumps that cause short-circuit risks.
Solution Approach 2:
The pad structure is given multiple functions: it serves as both an electrical connection element and a heat retaining wall. The extended pad regions perform dual roles of electrical bonding and thermal management, eliminating the need for separate dummy bumps.
2Reliability
If temperature is increased to improve soldering material wettability, then bonding reliability is improved, but non-uniform heat distribution causes defects
Solution Approach 1:
The patent applies local quality by creating regions with different thermal properties at different locations. Extended pad regions are strategically placed at array ends and gaps where heat loss is highest, providing localized heat retention without requiring uniform temperature increase across the entire array.
3Volume of moving object
If bump electrodes are spaced widely or placed at array ends, then device size is reduced, but heat escapes and bonding reliability deteriorates
Solution Approach 1:
The patent extends the heat retention function into the planar dimension by creating extended pad regions that protrude beyond the bump electrode array boundaries. This dimensional extension provides heat retention at array ends and gaps without requiring additional vertical space or increasing device thickness.
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 enhances bonding reliability by maintaining optimal heat distribution and preventing short-circuits, thereby reducing the size of semiconductor devices while improving their functionality and reliability.
Implementation Method 1
a heating unit for heating the wiring substrate and the semiconductor chip
Implementation Method 2
the soldering material pre-applied onto each of the bonding leads on the wiring substrate wets and rises onto the associated bonding lead to bond the bump electrode and the bonding lead with each other
Implementation Method 3
the soldering material pre-applied onto each of the bonding leads on the wiring substrate wets and rises onto the associated bonding lead
Implementation Method 4
the soldering material pre-applied onto each of the bonding leads on the wiring substrate wets and rises onto the associated bonding lead
Data Source
AI summary
The reliability of a semiconductor device is to be improved. A microcomputer chip (semiconductor chip) having a plurality of pads formed on a main surface thereof is mounted over an upper surface of a wiring substrate in an opposed state of the chip main surface to the substrate upper surface. Pads coupled to a plurality of terminals (bonding leads) formed over the substrate upper surface comprise a plurality of first pads in which a unique electric current different from the electric current flowing through other pads flows and a plurality of second pads in which an electric current common to the pads flows or does not flow. Another first pad of the first pads or one of the second pads are arranged next to the first pad. The first pads are electrically coupled to a plurality of bonding leads respectively via a plurality of bumps (first conductive members), while the second pads are bonded to the terminals via a plurality of bumps (second conductive members).