Composite Pillar Structure for Image Plane Flatness Under Thermal Stress
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Microelectronic hybrid devices experience image plane bowing due to thermo-mechanical stresses from differing coefficients of thermal expansion, leading to non-flat image surfaces and impaired optical performance, which prior attempts to mitigate with flat shims have failed to fully address.
Innovation Solution
A composite structure with a field array of discrete pillars, each with a tailored coefficient of thermal expansion, is used to compensate for the shrinkage and expansion of device components, reducing thermal expansion-induced deformations and stress by being arranged between two surfaces, potentially in a controlled distribution and arrangement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If flat shims are used under the integrated circuit to reduce stress, then some stress compensation is achieved, but the image plane bowing is not completely eliminated
Solution Approach 1:
The patent divides the shim structure into multiple discrete pillars instead of using a continuous flat shim. These pillars are distributed across the substrate and can be independently sized and positioned to provide localized stress compensation throughout the device, achieving complete bowing elimination rather than partial compensation.
Solution Approach 2:
The patent applies local quality by varying the dimensions, materials, and distribution of individual pillars based on the specific stress requirements at different locations. This allows tailored stress compensation in different regions of the device, enabling complete elimination of image plane bowing that uniform flat shims cannot achieve.
2Temperature
If components are subjected to extreme temperature conditions, then the device operates in its intended environment, but thermo-mechanical stresses cause bowing and stress on interconnect joints
Solution Approach 1:
The patent utilizes thermal expansion principles by selecting pillar materials with specific coefficients of thermal expansion that compensate for the differential expansion between components. The pillars are designed to expand and contract in a controlled manner to counteract the bowing forces generated during thermal cycling, thereby protecting interconnect joints from stress.
Solution Approach 2:
The patent employs composite materials by combining the substrate, integrated circuit, electronic device, and pillar structures with different thermal and mechanical properties. This composite structure allows the system to manage thermo-mechanical stresses through the coordinated response of different materials, maintaining interconnect joint reliability across extreme temperature ranges.
3Stability of the object's composition
If image plane bowing occurs, then the device structure responds to thermal stresses, but optical performance is impaired
Solution Approach 1:
The patent applies preliminary anti-action by pre-positioning the discrete pillars to counteract the anticipated thermal expansion and contraction forces before they occur during operation. The pillars are designed and arranged to provide preemptive stress compensation that prevents image plane bowing from developing, thereby maintaining optical performance throughout thermal cycling.
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 composite structure effectively normalizes the image plane, reducing thermo-mechanical stresses and achieving a substantially planar image surface, thereby enhancing the optical performance and reliability of microelectronic hybrid devices.
Implementation Method 1
The plurality of discrete pillars each have a tailored coefficient of thermal expansion and are designed to expand and contract over varying temperatures
Implementation Method 2
thermo-mechanical stresses are imparted on the device when it is subjected to these extreme temperature conditions
Data Source
AI summary
A composite structure includes a first surface and a second surface sandwiched together with a field array of individual and discrete pillars extending therebetween. The plurality of discrete pillars each have a tailored coefficient of thermal expansion and are designed to expand and contract over varying temperatures. The discrete pillars are specifically arranged within the composite structure to compensate for the shrinkage and expansion of different components of a microelectronic hybrid device, to reduce thermal expansion induced deformations imparted on facets of the microelectronic hybrid device under varying temperatures.