Ultrasonic Wire Bond Lead Clamping With Convex-Concave Surfaces
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Solution Overview
Problem
In semiconductor manufacturing, the instability of leads during ultrasonic wedge wire bonding leads to poor bonding quality due to unwanted movement, which can result in debris and shorts in the final IC package.
Innovation Solution
A clamping tool with complementary convex and concave force transmission surfaces is used to securely hold leads in place during bonding, reducing movement and friction, and thereby improving the bonding process by maintaining a consistent contact area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional clamping is used to hold leads during ultrasonic bonding, then lead stability is improved, but scratch build-up and debris occur between clamping tool and lead surface
Solution Approach 1:
The clamping tool employs a curved or rounded clamping surface instead of a flat surface. This curvature reduces the contact area concentration and distributes the clamping force more evenly, minimizing scratch build-up and debris generation while maintaining effective lead stability during ultrasonic bonding operations
2Manufacturing precision
If increased clamping force is applied to reduce lead movement, then bonding quality is improved, but friction and heat generation increase
Solution Approach 1:
The curved clamping surface reduces the coefficient of friction between the clamping tool and lead by distributing contact pressure more evenly. This allows adequate clamping force to be applied for bonding quality while minimizing excessive friction and heat generation that would occur with flat surface contact
3Ease of manufacture
If flat clamping surfaces are used between tool and lead, then manufacturing simplicity is maintained, but contact area consistency deteriorates during bonding
Solution Approach 1:
The curved clamping surface maintains consistent contact area during the bonding process by adapting to the lead geometry and distributing contact pressure evenly. While slightly more complex to manufacture than flat surfaces, the curvature ensures reliable and consistent bonding performance
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 solution enhances the stability of leads during ultrasonic bonding, reducing the risk of debris and shorts, and ensuring a higher quality bond by maintaining a consistent contact surface and minimizing friction.
Implementation Method 1
applying a pressure force to said electrically-conductive leads in said substrate during bonding
Implementation Method 2
Ultrasonic bonding can be performed at room temperature, using a combination of pressure and ultrasonic vibration to form a weld between two materials
Implementation Method 3
reducing the risk of debris and shorts in a final IC package... minimizing friction
Data Source
AI summary
In providing electrical wire-like connections between at least one semiconductor die arranged on a semiconductor die mounting area of a substrate and an array of electrically-conductive leads in the substrate, pressure force is applied to the electrically-conductive leads in the substrate during bonding the wire-like connections to the electrically-conductive leads. Such a pressure force is applied to the electrically-conductive leads in the substrate via a pair of mutually co-operating force transmitting surfaces. These surfaces include a first convex surface engaging a second concave surface.