Semiconductor Chip Bonding with a Metal Block Intermediary
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Solution Overview
Problem
Existing methods for bonding semiconductor chips and lead electrodes in semiconductor devices, such as ultrasonic bonding, can cause damage to the semiconductor chip and reduce bonding strength due to remelting of bonding materials, especially when using solder as a bonding material.
Innovation Solution
A semiconductor device design that includes a metal block with irregularities on its surface bonded to a lead electrode, allowing ultrasonic bonding between the metal block and lead electrode without directly applying ultrasonic vibration to the semiconductor chip, thereby protecting the chip from damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If ultrasonic bonding is applied to bond the lead electrode and semiconductor chip, then bonding strength is improved, but the semiconductor chip may be damaged
Solution Approach 1:
A metal block is introduced as an intermediary component between the semiconductor chip and lead electrode. The ultrasonic bonding is performed on the metal block rather than directly on the semiconductor chip, thereby transferring the bonding process away from the chip and preventing damage while maintaining bonding strength.
2Area of stationary object
If the entire semiconductor device is heated to bond the lead electrode and semiconductor chip, then bonding area is increased, but the bonding material between semiconductor chip and insulating substrate may be remelted
Solution Approach 1:
The bonding process is segmented into separate stages: first, the semiconductor chip is bonded to the insulating substrate at a lower temperature; second, the lead electrode is bonded to the metal block at a higher temperature. This segmentation allows each bonding operation to be optimized independently, preventing remelting of the first bonding material while achieving adequate bonding area.
3Ease of manufacture
If solder is used as bonding material between semiconductor chip and insulating substrate, then ease of manufacture is improved, but the rear surface electrode of the semiconductor chip diffuses into the solder and bonding strength is reduced
Solution Approach 1:
The metal block serves as an intermediary that prevents direct contact and diffusion between the semiconductor chip electrode and the solder. This eliminates the diffusion problem while maintaining the ease of manufacture associated with using solder as a bonding material.
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 design suppresses damage to the semiconductor chip during ultrasonic bonding, maintains bonding strength, and prevents remelting of bonding materials, ensuring stable and cost-effective manufacturing of semiconductor devices.
Implementation Method 1
the metal block and the lead electrode are ultrasonically bonded to each other
Data Source
AI summary
A semiconductor device according to the present disclosure includes a semiconductor chip, a metal block having a first surface and a second surface opposite to the first surface, the first surface being bonded to the semiconductor chip with a bonding material, and a lead electrode bonded to the second surface of the metal block, wherein a plurality of irregularities are formed on a surface of the lead electrode opposite to a surface thereof bonded to the metal block.