Semiconductor Module Ultrasonic Welding Particle Contamination
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Solution Overview
Problem
During ultrasonic welding of copper terminals to semiconductor modules, particles are produced that can contaminate critical areas, such as chip contacts and insulating ceramic, making it difficult to remove them and potentially impairing insulation, and existing solutions like enclosing structures or using foam are costly or ineffective.
Innovation Solution
A semiconductor module design with a housing that includes a protective wall creating a gap between the substrate and the protective wall, allowing a fluid flow to prevent particles from entering the protected region during welding, which can be blown out, thus maintaining insulation and reducing contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If an enclosing structure is placed around the welding point to prevent particle contamination, then particle protection is improved, but the metalized terminal welding point must be designed to be very large which increases device complexity and cost
Solution Approach 1:
The housing is segmented into a protected region (enclosed by the protective wall) and an unprotected region, allowing the welding operation to occur in the unprotected region while the protected region remains shielded. This segmentation enables particle prevention without requiring an overly large welding point design.
Solution Approach 2:
A protective wall is introduced as an intermediary structure between the welding point and the protected region. This wall acts as a barrier that prevents particles from reaching critical areas while allowing the welding process to proceed normally with standard-sized welding points.
2Object-affected harmful factors
If the enclosing structure is placed onto the insulating ceramic to prevent particle contamination, then particle protection is improved, but the insulating effect of the ceramic is reduced which worsens insulation performance
Solution Approach 1:
The protective wall provides localized protection only in the specific area where welding particles are generated, rather than covering the entire insulating ceramic surface. This localized approach prevents particles from reaching critical areas while preserving the insulating properties of the ceramic in other regions.
3Object-affected harmful factors
If a moving plastic part is used to enclose particles during welding, then particle protection is improved, but the plastic part may tear away the surrounding silicone gel which impairs insulation
Solution Approach 1:
Instead of using a moving plastic part that approaches the welding point from above (which could tear silicone gel), the protective wall is positioned such that it allows particles to be contained and removed by fluid flow from below or the side, inverting the traditional approach and avoiding mechanical damage to insulation materials.
4Object-affected harmful factors
If ultrasonic welding is carried out within foam to allow particle removal, then particle contamination is reduced, but the production process becomes cost-intensive which worsens manufacturing cost
Solution Approach 1:
Instead of using expensive reusable foam materials that require complex production processes, the invention employs a simple, inexpensive protective wall structure combined with a fluid flow system. The protective wall can be easily manufactured and integrated into the housing, providing effective particle containment without the high costs associated with foam-based solutions.
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 solution effectively prevents particle contamination within the semiconductor module, reducing failure rates and maintaining insulation integrity while being cost-effective by producing the protective wall simultaneously with the housing and allowing for efficient particle removal during the welding process.
Implementation Method 1
a gap is formed between the substrate and the protective wall, the gap being arranged to carry a fluid flow such that particles produced during the ultrasonic welding of the terminal foot to the terminal pad are prevented from penetrating into the protected region from the unprotected region
Implementation Method 2
particles produced during the ultrasonic welding of the terminal foot to the terminal pad
Data Source
AI summary
A semiconductor module includes a base plate, a substrate on the base plate and carrying at least one semiconductor chip, a housing attached to the base plate and at least partially enclosing the substrate, and at least one terminal having one end which protrudes from the housing and another end which has a terminal foot attached on a terminal pad of the metallization by means of ultrasonic welding. The housing has a protective wall which encloses the terminal and divides an interior space of the housing into an unprotected region and a protected region. The protective wall is formed such that a gap is formed between the substrate and the protective wall. The gap is designed to carry a fluid flow such that particles produced during the ultrasonic welding of the terminal foot to the terminal pad are prevented from penetrating into the protected region from the unprotected region.