Semiconductor Package Thinning via Dicing Saw Trimming
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Solution Overview
Problem
Existing semiconductor die packaging methods, such as back-grinding and molded array process, face challenges in achieving uniform thinning of semiconductor devices, which can lead to warping, cracking, and limitations in producing devices of varying thicknesses without additional equipment or process steps.
Innovation Solution
A method involving the use of a dicing saw to simultaneously assemble semiconductor devices of varying thicknesses by trimming the mold compound on top sides of packaged dies, allowing for different thicknesses to be achieved without additional equipment or process steps, while integrating this thinning into the normal dicing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If back-grinding is used to thin semiconductor wafers, then device thickness is reduced, but wafer warping and die cracking occur
Solution Approach 1:
The method performs preliminary actions by first assembling complete packages with full mold compound, then selectively removing material later. This reverses the traditional sequence of thinning before assembly, allowing the wafer to be supported by the mold compound during assembly to prevent warping and cracking, while still achieving the desired thin thickness afterward.
2Productivity
If molded array process is used to assemble devices, then assembly efficiency is improved, but all devices must have the same thickness
Solution Approach 1:
The method applies local quality by selectively removing different amounts of mold compound from different devices within the same array. The dicing saw can be programmed to remove varying thicknesses from specific locations, allowing each device to have its desired thickness while maintaining the efficiency of batch assembly. This enables customization within the molded array process without sacrificing productivity.
3Adaptability or versatility
If selective thinning is performed after molding, then varying thicknesses are achieved, but additional equipment or process steps are required
Solution Approach 1:
The method achieves universality by making the existing dicing saw perform multiple functions: it both separates individual devices from the array and selectively thins them to varying degrees. By programming the dicing saw with different depth parameters for different locations, the same equipment accomplishes both singulation and selective thinning, eliminating the need for additional specialized equipment or separate process steps.
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
Enables the production of semiconductor packages with varying thicknesses, improving reliability and yield by avoiding warping and cracking issues, and allowing for uniform thinning without additional resources or process changes.
Implementation Method 1
A first set of the devices is thinned with a saw blade by reducing an amount of the mold compound on the top sides thereof with the saw blade
Data Source
AI summary
A method of packaging a semiconductor die includes the steps of mounting the semiconductor die on a carrier, electrically connecting electrical contact pads of the semiconductor die to external electrical contacts, and encapsulating the die with a mold compound to form a packaged die. The packaged die is then thinned by using a dicing saw blade to trim the mold compound off of the top, non-active side of the package using a series of vertical cuts. This thinning step can be performed at the same time as a normal dicing step so no additional equipment or process steps are needed. Further, packages of varying thicknesses can be assembled simultaneously.