Force Resistant Circuit Module Design for Sensor Packages
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Solution Overview
Problem
Semiconductor sensor packages face mechanical stress issues due to external forces, leading to potential cracking or electrical failure, as existing solutions with compressible materials often fail to adequately absorb forces without causing the die to bend or peel away from the flexible circuit.
Innovation Solution
A circuit module design featuring a flexible circuit with a reinforcing layer and low modulus material, including a patterned gap to absorb forces and prevent peeling, along with a dry film adhesive for additional protection, ensures the die is securely mounted and protected from flexural and compressive loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If compressible material is placed beneath the sensor array to absorb forces, then force absorption is improved, but the die may bend or peel away from the flexible circuit
Solution Approach 1:
The patent applies different material properties in different locations: compressible material is placed only in specific interior regions beneath the sensor array to absorb forces, while gap regions are provided between the die edges and the compressible material to prevent peeling. This localized differentiation allows force absorption without compromising die attachment stability.
Solution Approach 2:
The interior region beneath the die is segmented into multiple zones: compressible material regions for force absorption and gap regions for preventing peeling. This segmentation allows the structure to simultaneously provide both force absorption and attachment stability without compromise.
2Ease of operation
If the sensor pad is exposed at an outer surface for user interaction, then ease of operation is improved, but the sensor becomes vulnerable to mechanical damage from external forces
Solution Approach 1:
Compressible material is pre-positioned in the interior region beneath the sensor array before external forces are applied. This beforehand cushioning allows the structure to absorb impending mechanical forces from user interaction or external impacts, protecting the sensor while maintaining accessibility.
3Ease of operation
If downward forces are applied to the sensor die, then sensing function is activated, but the die may peel away from the flexible circuit
Solution Approach 1:
The patent creates local quality differences by providing compressible material in specific interior regions while maintaining gap regions between the die edges and the compressible material. This allows downward forces to be absorbed for sensing activation while the gap regions prevent the die from peeling away from the flexible circuit.
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 effectively absorbs and distributes external forces, preventing damage to the semiconductor die and maintaining the integrity of the sensor package, thereby enhancing the reliability of semiconductor sensor packages in consumer devices.
Implementation Method 1
Low modulus material may also be disposed in the interior region and about the high modulus material in a manner sufficient to at least partially absorb compressive loads applied to the die
Implementation Method 2
the reinforcing layer has a coefficient of thermal expansion closely matching that of the die
Data Source
AI summary
Impact resistant circuit modules are disclosed for enclosing a die having a sensor area. Preferred modules include a flexible circuit and a die coupled thereto. The flexible circuit is preferably folded over compressible material to help absorb applied forces. A gap may be provided between sides of the die and the compressible material to help prevent peeling. A metal reinforcing layer may be bonded to the back of the die. A low modulus material including a patterned gap underneath the die may be used to absorb forces. A dry film adhesive may be placed between at least part of the upper surface of the die and the flexible circuit, preferably to provide further point impact resistance and protection. High and low modulus material may be combined in ruggedizing structures. Consumer devices employing such circuit modules are also taught, as well as module construction methods.