Sandblasting Tracks on LTCC Substrates Using Compatible Abrasives
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Solution Overview
Problem
Conventional screen printing techniques for forming tracks on LTCC substrates face challenges in achieving dimensional accuracy and reproducibility, being sensitive to environmental conditions, operator skills, and paste properties.
Innovation Solution
A method involving sandblasting with an abrasive material mixture of alumina and glass, compatible in thermal expansion and shrinkage with the LTCC substrate, to form tracks on non-conductive substrates, ensuring precise track formation independent of environmental conditions and operator skills, with the abrasive material being compatible in physical and chemical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional screen printing technique is used to form tracks on LTCC substrates, then the process is simple and widely applicable, but the dimensional accuracy and reproducibility of tracks cannot be achieved due to sensitivity to environmental conditions, operator skills, and paste properties
Solution Approach 1:
The track formation process is segmented into distinct stages: applying a sacrificial coating layer, placing a precision stencil, sandblasting to erode the coating, and removing the stencil. This segmentation allows each step to be optimized independently, with the stencil defining the exact track geometry and the sandblasting process precisely removing material without the variability inherent in direct screen printing
Solution Approach 2:
A sacrificial coating layer is introduced as an intermediary between the stencil and the LTCC substrate. This coating layer absorbs the abrasive action during sandblasting, protecting the substrate while allowing precise track definition through the stencil pattern. The coating is subsequently removed, leaving clean, accurately dimensioned tracks without direct contact between the abrasive and substrate
2Reliability
If conventional screen printing is used, then the equipment and process are straightforward, but environmental conditions, operator skills, and paste properties significantly affect track reproducibility
Solution Approach 1:
The sandblasting process is made self-regulating through the use of the sacrificial coating layer. The coating absorbs the abrasive particles and controls the erosion rate, automatically compensating for variations in blasting parameters. This eliminates the need for operator skill in controlling the exact amount of material removal, as the process self-limits to the thickness of the coating layer
Solution Approach 2:
The stencil serves as a precise copy or template of the desired track pattern. By transferring the stencil pattern onto the coating layer through sandblasting, the exact geometry is replicated without dependence on operator interpretation or skill. The stencil acts as a master pattern that ensures consistent reproduction across multiple tracks and substrates
3Manufacturing precision
If sandblasting with abrasive material is used to form tracks, then sharp and distinct tracks with accurate dimensions are achieved, but strain and stress may be induced on the LTCC substrate due to thermal expansion and shrinkage mismatches
Solution Approach 1:
The physical and chemical parameters of the abrasive material are specifically selected to match the LTCC substrate properties. The abrasive particles are made from materials with thermal expansion coefficients and shrinkage characteristics compatible with LTCC, ensuring that during the sandblasting process and subsequent firing, no differential stress or strain is induced on the substrate
Solution Approach 2:
The abrasive material is designed to be homogeneous in composition with the LTCC substrate, using the same or similar ceramic materials. This homogeneity ensures that the abrasive particles interact with the coating layer without creating stress concentrations or thermal mismatches in the substrate, maintaining structural integrity while achieving precise track formation
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 method achieves sharp, distinct, and accurately dimensioned tracks on LTCC substrates, reducing strain and stress on the substrate, and improving reproducibility by maintaining compatibility between the abrasive material and the substrate, thus overcoming the limitations of conventional screen printing.
Implementation Method 1
eroding the exposed portion of the layer of coating material by propelling an abrasive material using a blasting gun towards the assembly
Implementation Method 2
the abrasive material has a composition that has physical and chemical properties that are compatible with that of the non-conductive substrate
Implementation Method 3
the abrasive material has a composition that has physical and chemical properties that are compatible with that of the non-conductive substrate
Data Source
Figure 1
Figure 2A~2B
Figure 3A
AI summary
A method for forming track(s) on low temperature co-fired ceramic (LTCC) substrate, the method comprising the steps of, forming a layer of coating material on an operative face of the LTCC substrate, disposing a stencil on the layer of coating material thereby covering a selected portion of the layer of coating material while leaving exposed a portion of the layer of coating material corresponding to the track(s) to be formed and forming an assembly of the LTCC substrate, the layer of coating material and the stencil, eroding the exposed portion of the layer of coating material by propelling an abrasive material using a blasting gun towards the assembly on the face on which the layer of coating material is formed and the stencil is disposed and separating the stencil from the abraded assembly, wherein the abrasive material has a composition that is compatible with that of the LTCC substrate.