SAW Device Protector Prevents Substrate Chipping
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Solution Overview
Problem
Surface acoustic wave devices (SAW devices) suffer from chipping during the dicing process due to the use of rotary blades, leading to substrate damage and subsequent cracking under thermal loading during molding and heat cycles, as the molding resin penetrates into chipped areas and expands differently than the substrate.
Innovation Solution
The electronic component package incorporates a protector made of epoxy resin with fillers on the substrate's opposing surface, which provides a high coefficient of elasticity to prevent bending and chipping during dicing, and a silicon cover with recessed areas forming cavities for surface acoustic waves, along with an adhesive portion and external terminals, to enhance thermal reliability and reduce substrate damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If SAW device is diced by rotary blade after mounting on board, then individual components are separated, but substrate chipping occurs leading to cracking under thermal loading
Solution Approach 1:
A dicing prevention layer is formed on the substrate surface before the dicing process. This layer prevents the rotary blade from directly contacting and chipping the substrate during dicing, while being removable afterward to allow proper bonding of the substrate to the mounting board.
Solution Approach 2:
The dicing prevention layer acts as an intermediary between the rotary blade and the substrate. It absorbs the mechanical stress of the dicing process, preventing direct damage to the substrate while allowing the dicing operation to proceed effectively.
2Ease of manufacture
If molding resin is applied to cover the component, then packaging is completed, but resin penetrates into chipped portions causing cracks during cooling
Solution Approach 1:
The dicing prevention layer is applied before dicing to prevent chipping at the source. By preventing substrate damage beforehand, the subsequent molding process can proceed without risk of resin penetration into chipped areas, eliminating the need for additional defect repair steps.
Solution Approach 2:
The invention converts the potential harm of substrate chipping into a benefit by using the dicing prevention layer to control where the blade cuts. The layer allows clean separation while protecting the substrate, turning a problematic dicing process into a precise and safe operation.
3Reliability
If dicing sheet is used to prevent chipping, then substrate protection is improved, but additional peeling step is required increasing process complexity
Solution Approach 1:
The dicing prevention layer is designed with specific material properties that allow it to be easily removed after dicing without requiring a separate peeling step. The layer's composition and adhesion characteristics are optimized so that it naturally detaches or integrates seamlessly into the subsequent bonding process, reducing overall process complexity.
Solution Approach 2:
The removal of the dicing prevention layer is merged with the bonding process. As the substrate is bonded to the mounting board, the prevention layer is simultaneously removed or integrated, combining two process steps into one and reducing overall manufacturing 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 configuration significantly reduces substrate chipping and improves thermal reliability by preventing bending and cracking, ensuring the electronic component package's integrity under thermal loading and simplifying the manufacturing process by eliminating the need for peeling off a conventional dicing sheet.
Implementation Method 1
Surface acoustic wave device (hereafter referred to as 'SAW device') 1, an example of electronic components
Implementation Method 2
The substrate composed of piezoelectric body has a first surface on which the device is disposed
Implementation Method 3
Since molding resin 9 has a lower coefficient of linear expansion than substrate 2, substrate 2 contracts greater than molding resin 9 when molding resin 9 is cooled down
Implementation Method 4
molding resin 9 has a lower coefficient of linear expansion than substrate 2
Data Source
AI summary
The electronic component package includes a mounting board, an electronic component and a molding resin. An external electrode is disposed on a surface of the mounting board. The electronic component connected to the mounting board via the external electrode includes a component-substrate, a device, a component-cover and a protector made of resin. The component-substrate comprising a piezoelectric body includes a first surface on which the device is disposed and a second surface opposing the first surface. The component-cover covers the first surface of the substrate and the device. The protector provided on the second surface contains filler. The molding resin covers the electronic component on the mounting board.