Metallic Adhesive Layer for Semiconductor Chip Placement
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Solution Overview
Problem
Conventional methods for fixing semiconductor chips on surfaces often require organic fluxes or temporary adhesives, leading to contamination and complex cleaning processes, as well as issues with placement accuracy and creep resistance during soldering.
Innovation Solution
A method involving the application of a solder compound and a metallic adhesive layer, where the surface is preheated to facilitate partial melting of the adhesive layer, allowing for metallurgical bonding without organic fluxes, and a barrier layer is used to prevent material mixing, enabling improved placement accuracy and creep resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If organic fluxes or temporary adhesives are used for fixing semiconductor chips, then placement accuracy is improved, but organic contamination occurs and cleaning complexity increases
Solution Approach 1:
The invention extracts and eliminates organic fluxes and temporary adhesives from the chip assembly process. By using a metallic adhesive layer that can be selectively removed without organic materials, the harmful organic contamination is completely removed from the system, solving the contradiction between placement accuracy and organic contamination.
Solution Approach 2:
The invention changes the material parameter from organic-based adhesives to metallic-based adhesive layer. This parameter change allows the adhesive to provide sufficient holding force for accurate placement while being completely inorganic and easily removable without contamination, thus resolving the contradiction.
2Ease of manufacture
If conventional fixing methods are used, then assembly process is simple, but creep resistance during soldering deteriorates
Solution Approach 1:
The invention uses a composite structure consisting of a metallic adhesive layer with specific compositional ranges (e.g., In-Sn-Bi system) that combines low melting point for easy application with high creep resistance for reliable soldering. This composite material approach maintains assembly simplicity while dramatically improving creep resistance during subsequent soldering processes.
Solution Approach 2:
The invention optimizes the compositional parameters of the metallic adhesive layer, specifically controlling the ratios of In, Sn, and Bi components to achieve a eutectic or near-eutectic composition. This parameter optimization ensures the adhesive melts at a low temperature for easy application but maintains exceptional creep resistance during high-temperature soldering, resolving the contradiction between manufacturing ease and reliability.
3Object-generated harmful factors
If metallic adhesive layer is applied, then organic contamination is eliminated, but placement accuracy may deteriorate
Solution Approach 1:
The invention carefully controls the thickness parameter of the metallic adhesive layer within a specific range (e.g., 1-10 micrometers) and optimizes the compositional parameters to ensure the layer provides sufficient bonding strength for accurate placement while remaining thin enough to maintain precision. The low melting point of the optimized composition allows the layer to become sufficiently fluid for accurate chip placement before solidifying to provide holding force.
Solution Approach 2:
The metallic adhesive layer is designed as a composite material system (e.g., In-Sn-Bi alloy) that combines multiple metallic elements to achieve optimal properties: low melting point for easy application and placement, sufficient viscosity control for positioning accuracy, and strong bonding for holding. This composite approach eliminates organic contamination while maintaining or even improving placement accuracy compared to conventional organic adhesives.
4Object-generated harmful factors
If barrier layer is used to prevent material mixing, then material purity is improved, but device complexity increases
Solution Approach 1:
The invention extracts and removes the barrier layer from the structure by using a metallic adhesive layer composition and process that inherently prevents unwanted material mixing through controlled metallurgical bonding. The optimized In-Sn-Bi adhesive layer forms controlled intermetallic compounds with the solder compound without requiring a separate barrier layer, thus eliminating the additional structural complexity while maintaining material purity.
Solution Approach 2:
The invention applies local quality control by optimizing the compositional gradient and thickness distribution within the metallic adhesive layer itself. By creating a compositionally graded adhesive layer that transitions from high In content (for low melting point) to higher Sn content (for bonding strength), the layer provides both the adhesive function and the barrier function locally, eliminating the need for a separate barrier layer and reducing overall device complexity.
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 method eliminates organic contamination, simplifies the assembly process, enhances creep resistance, and allows for precise placement of semiconductor chips with reduced cleaning complexity and improved soldering outcomes.
Implementation Method 1
the metallic adhesive layer is brought into mechanical contact with the preheated surface, the metallic adhesive layer at least partially melting during the bringing in mechanical contact with the preheated surface
Implementation Method 2
The adhesive effect can be caused by surface tension, for example, and makes it possible to hold the semiconductor chip in position on the surface
Implementation Method 3
the surface is subsequently cooled to room temperature, whereby the semiconductor chip is at least partially metallurgically bonded to the surface
Data Source
AI summary
In an embodiment a method for producing a semiconductor component comprising at least one semiconductor chip mounted on a surface, wherein the semiconductor chip is fixed on the surface by applying a solder compound to an assembling surface of the semiconductor chip, applying a metallic adhesive layer to a side of the solder compound facing away from the assembling surface, preheating the surface to a first temperature T1, bringing the metallic adhesive layer into mechanical contact in a solid state with the preheated surface, the metallic adhesive layer at least partially melting while it is brought into mechanical contact with the preheated surface, and subsequently cooling the surface to room temperature, the semiconductor chip being at least partially metallurgically bonded to the surface, and wherein the semiconductor chip is subsequently soldered to the surface to form a resulting solder connection.