Semiconductor Package Cavity Structure for Low-Warpage Molding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current semiconductor devices face challenges in heat dissipation due to the poor thermal conductivity of resin or ceramic circuit boards, leading to deformation and cracking issues during the transfer molding process, especially at dicing lines, and existing solutions like support pins increase manufacturing costs and are inflexible to conductor thickness fluctuations.
Innovation Solution
A semiconductor device design featuring a board with a cavity and back-side conductor, where the mold material is interconnected through holes in the board, allowing equal pressure application from both sides and reducing warpage, thus preventing deformation and peeling, while eliminating the need for costly machining of support pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the thickness of the back-side conductor is increased to enhance heat dissipation capability, then the heat dissipation capability is improved, but the gap between the bottom face of the board and the die becomes larger, causing larger deformation of the board during transfer molding
Solution Approach 1:
The invention divides the mold into two separate molds: an upper mold for the front side and a lower mold for the back side. This segmentation allows independent control of molding pressure on each side, enabling the application of higher pressure on the back side to compensate for the larger gap caused by the thick conductor, thereby reducing board deformation while maintaining enhanced heat dissipation capability
Solution Approach 2:
The invention inverts the conventional single-side molding approach by applying molding pressure from both the front and back sides simultaneously. This bidirectional pressure application counteracts the board deformation that would otherwise occur due to the large gap created by the thick back-side conductor, solving the contradiction between heat dissipation enhancement and manufacturing precision
2Manufacturing precision
If another back-side conductor is disposed additionally at the intersection point of dicing lines to prevent wide intervals, then the board deformation is reduced, but the load on the dicing blade becomes very large, causing rapid abrasion and breakage
Solution Approach 1:
The invention segments the molding process into two independent operations with separate molds, eliminating the need for additional back-side conductors at dicing line intersections. This approach reduces the mechanical load on the dicing blade while still achieving board deformation control through bidirectional pressure application during molding
Solution Approach 2:
The invention extracts the function of preventing board deformation from the structural design (additional conductors) and transfers it to the molding process design (bidirectional pressure application). This eliminates the need for extra conductors that would increase dicing blade load, thereby preserving dicing blade durability while maintaining manufacturing precision
3Manufacturing precision
If support pins are provided on the molding die to support the circuit board, then the board deformation is prevented, but the cost of the die increases due to special machining
Solution Approach 1:
Instead of adding support pins that protrude into the mold cavity, the invention inverts the approach by applying pressure from the back side through a dedicated lower mold. This eliminates the need for complex die machining while achieving the same effect of preventing board deformation during molding
4Manufacturing precision
If support pins are used to support the circuit board, then the board deformation is prevented, but the height of the support pin is fixed, so it cannot follow up the fluctuation of the thickness of the back-side conductor
Solution Approach 1:
The invention replaces the fixed-height support pin with a flexible lower mold that can adapt to varying conductor thicknesses. The lower mold applies distributed pressure across the back side of the board, dynamically adjusting to thickness fluctuations without requiring precise height matching, thereby maintaining manufacturing precision while enhancing adaptability
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 design enhances heat dissipation capabilities, reduces manufacturing costs, and adapts to conductor thickness fluctuations, preventing deformation and peeling of the mold material from the board, while allowing increased molding pressure without voids or unfilled states.
Implementation Method 1
the mold material has a portion on the front side of the board and a portion on the back side thereof that are interconnected through at least one hole provided in the board
Data Source
AI summary
Provided here are: a board; a cavity region therein having an opening created on a front side of a central portion of the board; a back-side conductor that is formed for the board to provide a bottom portion of the cavity region; a semiconductor chip mounted on the back-side conductor; and a mold material that covers the semiconductor chip and the board; wherein the mold material has a portion on the front side of the board and a portion on the back side thereof that are interconnected through at least one hole provided in the board, thereby to prevent failures such as a deformation, a crack, etc. of the board; and to reduce the warpage of the board to prevent the mold material from being peeled off therefrom.