Substrate Weld Line Layout for Hermetic Chip Dicing
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Solution Overview
Problem
Current methods for dicing hermetically sealed singulated chips, such as using sawing blades, scribing, or laser perforation, often result in impaired hermeticity, uneven wear of tools, unclean breaking edges, chipping, and irregular etching rates, which compromise the quality and integrity of the chips.
Innovation Solution
Introducing inner weld lines between outer weld lines in the dicing area of substrates allows for more uniform wear of sawing blades, precise breaking, and uniform etching rates, while preventing etching fluid from reaching the bonding interface, thereby enhancing edge-strength and hermeticity of singulated chips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sawing blade is used to cut between weld lines, then dicing can be performed, but the sawing blade experiences uneven wear and tool lifetime is reduced
Solution Approach 1:
Inner weld lines are introduced into the substrates before the dicing process. These pre-formed lines serve as guide structures that direct the sawing blade along predetermined paths, preventing random contact with outer weld lines and ensuring uniform wear distribution across the blade surface.
2Productivity
If mechanical breaking is used to separate substrates, then dicing can be performed, but unclean breaking edges and chipping occur
Solution Approach 1:
Inner weld lines are created in advance within the dicing area to serve as pre-defined separation paths. When mechanical breaking is applied, these pre-formed lines guide the fracture process, ensuring that breaks occur cleanly along the intended paths without chipping or unclean edges.
3Productivity
If laser perforation and etching are used to separate substrates, then dicing can be performed, but etching rates are irregular and etching fluid may reach the bonding interface
Solution Approach 1:
Inner weld lines are introduced before the etching process to create predetermined etching paths. These pre-formed lines guide the etching fluid flow and laser perforation, ensuring uniform etching rates and preventing etching fluid from deviating toward the bonding interface.
4Device complexity
If dicing is performed without inner weld lines, then the process is simpler, but edge-strength of singulated chips is reduced
Solution Approach 1:
The dicing area is segmented into multiple zones by introducing inner weld lines between the outer weld lines. This segmentation creates multiple reinforcement points along the edges of singulated chips, distributing stress and significantly improving edge-strength without requiring complete structural redesign.
5Device complexity
If dicing is performed without inner weld lines, then the process is simpler, but hermeticity of singulated chips is impaired
Solution Approach 1:
Inner weld lines divide the dicing area into segmented zones that act as hermetic barriers. When dicing occurs between these lines, the inner weld lines prevent etching fluid or stress from reaching the outer weld lines, preserving the hermetic seal integrity of each singulated chip.
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 presence of inner weld lines in the dicing area leads to improved edge-strength, reduced tool wear, and consistent dicing quality, regardless of the dicing method used, resulting in higher-quality singulated chips with enhanced hermeticity.
Implementation Method 1
a first and a second substrate are brought in contact with each other such that a contact area between the two substrates is formed. At least two outer weld lines extending next to each other within the contact area are introduced into the first and second substrates such that the first and second substrates are welded together by each of the outer weld lines
Implementation Method 2
the substrates may be cut by means of a sawing blade
Implementation Method 3
first preseparating the substrates by introducing laser perforations into the substrate
Implementation Method 4
then etching apart the substrates along the pre-separation lines
Data Source
Figure 1~3
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Figure 7~8
AI summary
The invention relates to a method for welding substrates comprising: bringing a first substrate and a second substrate in contact with each other such that a contact area between the two substrates is formed; introducing at least two outer weld lines extending next to each other within the contact area into the first and second substrates such that the first and second substrates are welded together by each of the outer weld lines and such that a dicing area is defined between the two outer weld lines; and introducing one or more inner weld lines extending between the two outer weld lines within the dicing area into at least one of the two substrates. The invention further relates to welded substrates and to singulated chips, in particular hermetically sealed enclosures.