Substrate-Integrated Stiffeners for Semiconductor Warpage Control
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Solution Overview
Problem
Current semiconductor packaging technologies face challenges with warpage due to thermal expansion mismatches and require complex assembly processes, and thermal management issues due to limitations in thermal interface materials and stiffener designs.
Innovation Solution
The use of high throughput additive manufacturing to create substrate-integrated posts and heat spreaders, and highly conductive layers directly on dies, allowing for customized thermomechanical solutions and improved thermal management without the need for traditional stiffeners or backside metallization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If discrete stiffeners are attached to substrate using epoxy layer, then warpage control is improved, but assembly complexity increases and throughput decreases
Solution Approach 1:
The stiffener structure is merged with the substrate by directly forming the stiffener on the substrate surface, eliminating the need for separate stiffener components and epoxy adhesive layers. This integration reduces the number of assembly steps and materials while maintaining warpage control functionality.
Solution Approach 2:
The epoxy adhesive layer is extracted/removed from the assembly process. By directly forming the stiffener on the substrate, the patent eliminates the intermediate epoxy layer that was previously required to attach discrete stiffeners, simplifying the overall structure and assembly process.
2Stability of the object's composition
If discrete stiffeners are attached using epoxy layer, then warpage mitigation is achieved, but thermal conductivity decreases
Solution Approach 1:
The epoxy adhesive layer is removed from the thermal path between the stiffener and substrate. By directly forming the stiffener on the substrate, the patent eliminates the thermally resistive epoxy layer, enabling more efficient heat transfer from the die through the stiffener to the substrate.
Solution Approach 2:
The patent uses metal or thermally conductive materials for the stiffener that are directly bonded to the substrate, creating a composite structure with superior thermal conductivity compared to the epoxy-based attachment method. This allows effective heat sinking while maintaining mechanical stiffness.
3Stability of the object's composition
If thin discrete stiffeners are used, then warpage control is improved, but handling difficulty increases
Solution Approach 1:
The stiffener is merged with the substrate as a single integrated component formed by direct deposition. This eliminates the need to handle, position, and attach separate thin stiffener components, making the manufacturing process easier and more reliable.
4Device complexity
If one-piece stiffener is used, then assembly steps are reduced, but substrate surface area consumption increases
Solution Approach 1:
The stiffener is segmented into multiple separate structures distributed across the substrate rather than using a single large one-piece stiffener. This segmentation reduces the total surface area consumed on the substrate while still providing effective warpage control through distributed support points.
5Adaptability or versatility
If semi-additive deposition is used to form stiffener, then material selection is limited, but manufacturing speed decreases
Solution Approach 1:
The patent replaces the slow electrochemical process of electroplating with a mechanical direct deposition process. This mechanical approach enables faster formation of stiffener structures while expanding material options to include various metals, metal alloys, and composite materials that can be directly deposited.
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 approach reduces warpage and thermal resistance, enhances packaging reliability, and enables the use of various materials and designs for improved thermomechanical performance and assembly efficiency.
Implementation Method 1
high throughput additive manufacturing to create substrate-integrated posts and heat spreaders
Implementation Method 2
highly conductive layers deposited on dies using high throughput additive deposition
Implementation Method 3
warpage generated as a result of the mismatch in the coefficient of thermal expansion (CTE) between a thin die and a substrate
Data Source
AI summary
Device package and method of forming a device package are described. The device package has a substrate with dies disposed on the substrate. Each die has a bottom surface that is electrically coupled to the substrate and a top surface. The device package further includes a plurality of stiffeners disposed directly on the substrate. The stiffeners may be directly attached to a top surface of the substrate without an adhesive layer. The device package may include stiffeners with one or more different sizes and shapes, including at least one of a rectangular stiffener, a picture frame stiffener, a L-shaped stiffener, a H-shaped stiffener, and a round pillar stiffener. The device package may have the stiffeners disposed on the top surface of the substrate using a cold spray process. The device package may also include a mold layer formed around and over the dies, the stiffeners, and the substrate.