Wire Bonded Leadframe Package With Dielectric Die Support
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Solution Overview
Problem
Conventional chip-on-lead (COL) semiconductor device packages face challenges in achieving reliable wire bonds due to lack of mechanical support beneath the semiconductor die, leading to weak or failed connections, and require careful design and tooling adjustments, which restrict size reduction and increase costs.
Innovation Solution
Incorporating a dielectric die support in the central portion of the leadframe, providing mechanical support for the semiconductor die, allowing standard wire bonding processes to be used without modifications, and using die attach material to mount the die, ensuring reliable connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a semiconductor die is mounted on a central lead in a COL package, then the package area is reduced, but the mechanical support beneath the die is insufficient leading to weak wire bonds
Solution Approach 1:
The support structure is segmented into a central lead for electrical connection and a dielectric die support structure for mechanical support. This segmentation allows the central lead to remain small for area reduction while the separate dielectric structure provides adequate support for wire bonding, resolving the contradiction between package size and wire bond reliability.
Solution Approach 2:
A dielectric die support structure is introduced as an intermediary between the central lead and the semiconductor die. This intermediary provides the necessary mechanical support for wire bonding while allowing the central lead to remain small, thus maintaining both area reduction and wire bond reliability.
2Ease of manufacture
If wire bonding is applied to a semiconductor die on a conventional COL package, then electrical connections are made, but the lack of mechanical support causes weak or failed bonds requiring process modifications
Solution Approach 1:
The dielectric die support structure is formed beforehand to provide mechanical cushioning and support during the wire bonding process. This pre-established support structure prevents wire bond failure without requiring modifications to the wire bonding process parameters, maintaining ease of manufacture while improving reliability.
3Reliability
If bond pads and leads are carefully placed to ensure reliable connections, then wire bond reliability improves, but design flexibility is restricted
Solution Approach 1:
The dielectric die support structure provides self-service by automatically providing mechanical support where needed during wire bonding. This eliminates the need for careful coordination between bond pad and lead placement, as the support structure inherently ensures bonding success, thereby restoring design flexibility while maintaining reliability.
4Area of stationary object
If the central lead is made smaller to reduce package area, then area reduction is achieved, but mechanical support for the die is insufficient
Solution Approach 1:
The support function is segmented from the electrical connection function. The central lead remains small for area reduction while the separate dielectric die support structure provides the necessary mechanical support strength, allowing both area reduction and adequate support strength to be achieved simultaneously.
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
Enables flexible placement of bond pads and leads, supports the entire semiconductor die during bonding, and maintains package size reduction while ensuring reliable wire bonds without additional costs or process modifications.
Implementation Method 1
A conductive wire or ribbon is bonded to bond pads on the semiconductor device using ultrasonic and thermal energy
Implementation Method 2
A conductive wire or ribbon is bonded to bond pads on the semiconductor device using ultrasonic and thermal energy
Implementation Method 3
A conductive wire or ribbon is bonded to bond pads on the semiconductor device using ultrasonic and thermal energy
Implementation Method 4
A conductive wire or ribbon is bonded to bond pads on the semiconductor device using ultrasonic and thermal energy
Data Source
AI summary
In a described example, an apparatus includes: a metal leadframe including a dielectric die support formed in a central portion of the leadframe, and having metal leads extending from the central portion, portions of the metal leads extending into the central portion contacted by the dielectric die support; die attach material over the dielectric die support; a semiconductor die mounted to the dielectric die support by the die attach material, the semiconductor die having bond pads on a device side surface facing away from the dielectric die support; electrical connections extending from the bond pads to metal leads of the leadframe; and mold compound covering the semiconductor die, the electrical connections, the dielectric die support, and portions of the metal leads, the mold compound forming a package body.