Variable Thickness Mold Cap Warpage Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional electronic packages face design challenges due to warpage caused by thermal mismatch between materials, leading to cracking and reliability issues, particularly after being cut or diced into singulated units, as existing solutions primarily focus on reducing warpage at the strip level.
Innovation Solution
The electronic package features a mold cap with variable thickness, designed to compensate for predicted warpage by incorporating mound-shaped and dimple-shaped portions, which are determined through modeling and testing to increase stiffness and absorb internal stresses, thereby maintaining package flatness and preventing detachment from substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional uniform thickness mold cap is used, then manufacturing process is simple, but warpage occurs due to thermal mismatch between materials
Solution Approach 1:
The mold cap is designed with variable thickness, featuring mound-shaped and dimple-shaped portions at specific locations. This local variation in thickness compensates for predicted warpage in different regions of the package, allowing each area to have the appropriate stiffness to counteract thermal mismatch effects while maintaining overall package flatness.
Solution Approach 2:
The variable thickness profile of the mold cap is determined through modeling and testing to predict and compensate for warpage before the package is manufactured. By pre-designing the thickness distribution to counteract expected thermal deformation, the package maintains flatness without requiring additional warpage correction steps during manufacturing or assembly.
2Reliability
If variable thickness mold cap is used, then warpage is reduced in singulated packages, but manufacturing complexity increases
Solution Approach 1:
The thickness parameter of the mold cap is varied continuously or in discrete steps to create mound-shaped and dimple-shaped portions. This parameter change allows the mold cap to have different stiffness characteristics in different regions, enabling compensation for warpage while still being manufactured as a single integrated component using conventional molding processes.
3Ease of manufacture
If uniform thickness mold cap is used, then manufacturing process is conventional, but warpage causes cracking and detachment after dicing
Solution Approach 1:
The variable thickness mold cap is designed to absorb and compensate for internal stresses and warpage forces before they can cause harmful effects. The mound-shaped portions provide additional stiffness in regions prone to convex warpage, while dimple-shaped portions accommodate concave warpage, preventing cracking and detachment during the dicing process and subsequent handling.
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 variable thickness mold cap effectively reduces or eliminates warpage in singulated electronic packages, enhancing their reliability and ability to mount on printed circuit boards without additional materials or assembly steps, while maintaining similar manufacturing processes as conventional packages.
Implementation Method 1
the coefficient of thermal expansion can be different for each material that forms an electronic package, and the thermal mismatch between materials can result in cracking, warpage, etc.
Data Source
Figure 1~2
Figure 3~7
Figure 8
AI summary
An electronic package with improved warpage compensation. The electronic package includes a mold cap having a variable thickness. The variable thickness can have a mound or dimple design. In another embodiment, a method is provided for reducing unit warpage of an electronic package by designing the topography of a mold cap to compensate for warpage.