Laser-Sintered Chip Arrangement With Single High-Current Contact
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Solution Overview
Problem
Existing chip arrangements for power transistors face challenges with high thermal and electrical stresses, leading to component failure, and are costly due to the need for multiple contact conductors to transmit high currents, with solder connections limited by temperature and prone to disconnection.
Innovation Solution
A method involving a sinter paste with at least 40% silver or copper applied to chip and conductor material track contact surfaces, followed by immersion of a contact conductor and sintering with laser energy to form a durable and high-temperature-resistant contact connection, reducing the need for multiple conductors and minimizing mechanical strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple contact conductors are used to transmit high currents, then the current transmission capability is improved, but the device complexity and production cost increase
Solution Approach 1:
The patent combines multiple contact conductors into a single contact conductor by applying a sinter paste with high silver or copper content (at least 40%) that creates a highly conductive sintered connection. This single conductor with enhanced material properties replaces the need for multiple conductors, reducing device complexity while maintaining high current transmission capability.
Solution Approach 2:
The patent changes the material parameters of the contact connection by using a sinter paste containing at least 40% silver or copper. This parameter change in material composition and structure enables a single contact conductor to achieve the current transmission capability that previously required multiple conductors.
2Ease of manufacture
If solder connections are used to connect chip and conductor material track, then the ease of manufacture is improved, but the reliability under high thermal and electrical stresses deteriorates
Solution Approach 1:
The patent changes the fundamental parameters of the connection method by replacing soldering with a sintering process using high silver or copper content paste. This parameter change in material composition and process temperature enables the formation of a reliable connection that can withstand high thermal and electrical stresses while remaining manufacturable through automated application processes.
Solution Approach 2:
The patent uses a composite material system consisting of a sinter paste with at least 40% silver or copper combined with a suitable binder. This composite material provides both the ease of application characteristic of solder paste and the high reliability needed for withstanding thermal and electrical stresses, creating a connection superior to traditional soldering.
3Reliability
If high temperatures are used to form contact connections, then the conductivity and service life are improved, but the chip and surrounding components may be damaged
Solution Approach 1:
The patent applies local quality by concentrating the high temperature sintering process only at the contact connection points where the sinter paste is applied. The laser beam is focused on specific locations to sinter the paste without heating the entire chip or surrounding components to damaging temperatures. This localized heating achieves high reliability connections while avoiding thermal damage to sensitive areas.
Solution Approach 2:
The patent replaces conventional thermal field sintering with a localized laser beam sintering process. This substitution of the heating mechanism allows precise control of thermal energy delivery, concentrating heat only where needed to form the connection while minimizing thermal exposure to the chip and surrounding components, thereby improving reliability without causing thermal damage.
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 significantly increases the service life and resistance to temperature fluctuations of the contact connection, enhances conductivity, and reduces production costs by allowing fewer contact conductors and minimizing thermal strain, while maintaining high current transmission capabilities.
Implementation Method 1
The sinter paste can be applied by screen printing, stencil printing or direct dispensing. The solvent contained in the sinter paste is at least partially vaporized by heating and the contact connection is formed by sintering the sinter paste by means of laser energy.
Implementation Method 2
The solvent contained in the sinter paste is at least partially vaporized by heating
Data Source
AI summary
A method for forming a contact connection between a chip-and a conductor material formed on a non-conductive substrate, the chip being arranged on the substrate or on another conductor material track, a sinter paste consisting of at least 40% silver or copper being applied to respective chip contact surfaces of the chip and the conductor material track, a contact conductor being immersed in the sinter paste on the chip contact surface and in the sinter paste on the conductor material track, and the contact connection being formed by sintering the sinter paste by means of laser energy.