Insulating Sheet Bonding to Semi-Cured Semiconductor Lead Frame
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Solution Overview
Problem
The existing semiconductor device manufacturing method faces issues with heat dissipation and reliability due to corrugation between die pads and insulating sheets, which increases manufacturing costs and requires frequent changes in insulating sheet specifications and complex conveyance mechanisms.
Innovation Solution
A method involving the use of a semi-cured lead frame with a die pad and terminal part, encapsulation with a semi-cured encapsulation material, and pressure-bonding an insulating sheet to the rear surface of the semi-cured unit, followed by curing, to form a semiconductor device with improved heat dissipation properties without the need for complex mold specifications or conveyance mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If die pads are pressed against the insulating sheet with pressing pins during encapsulation, then the insulating sheet is positioned in the mold, but corrugation occurs between the die pads and insulating sheet at areas farther from the pressing pins, deteriorating heat dissipation property
Solution Approach 1:
The insulating sheet is pre-bonded to the lead frame before encapsulation in a preliminary bonding step. This preliminary action ensures the insulating sheet is securely fixed to the lead frame, preventing corrugation during subsequent encapsulation and curing processes, thereby maintaining heat dissipation performance while simplifying the manufacturing process
2Adaptability or versatility
If the insulating sheet specifications are changed according to mold specifications, then the insulating sheet fits the mold, but the specifications of the insulating sheet need to be revised for each mold, increasing manufacturing cost
Solution Approach 1:
The insulating sheet is bonded to the lead frame, which serves as a universal carrier that can be adapted to different mold specifications. This universal approach allows the same insulating sheet design to be used across multiple mold types, eliminating the need to revise insulating sheet specifications for each mold and reducing manufacturing costs
3Ease of operation
If a conveyance mechanism is used to place the insulating sheet in the mold, then the insulating sheet can be positioned, but the conveyance mechanism becomes complex and expensive
Solution Approach 1:
The insulating sheet is integrated with the lead frame through bonding, combining two components into a single assembly. This merging eliminates the need for separate conveyance mechanisms to handle the insulating sheet independently, simplifying the overall device and reducing complexity and cost
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 approach enhances heat dissipation and reliability while reducing manufacturing costs by eliminating corrugation and simplifying the process, allowing for consistent production without mold-specific insulating sheet adjustments.
Implementation Method 1
a curing step of curing the semi-cured unit and the insulating sheet by heating
Data Source
AI summary
A method of manufacturing a semiconductor device, including: preparing a power semiconductor chip, a lead frame having a die pad part and a terminal part integrally connected to the die pad part, and an insulating sheet in a semi-cured state; disposing the power semiconductor chip on a front surface of the die pad part and performing wiring; encapsulating the lead frame and the power semiconductor chip with an encapsulation raw material in a semi-cured state, to thereby form a semi-cured unit, the terminal part projecting from the semi-cured unit, and a rear surface of the die pad part being exposed from a rear surface of the semi-cured unit; pressure-bonding a front surface of the insulating sheet to the rear surface of the semi-cured unit to cover the rear surface of the die pad part; and curing the semi-cured unit and the insulating sheet by heating.