Dice Ledge Structure for Underfill Warpage Control
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Solution Overview
Problem
In semiconductor device manufacturing, capillary forces can cause underfill materials to draw up between adjacent dice during the curing process, leading to warpage of the underlying substrate, which is not effectively addressed by existing methods.
Innovation Solution
Forming ledges along the edges of dice by using multiple dicing procedures with varying notch widths and depths to limit the upward movement of underfill materials, thereby reducing substrate warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If underfill material is placed between dice and substrate, then structural support and environmental protection are provided, but capillary forces cause underfill material to draw up between adjacent dice leading to substrate warpage
Solution Approach 1:
The patent applies preliminary action by forming ledges on the dice surfaces before underfill material is applied. These ledges are created through selective removal of molding compound or direct dicing, and they pre-establish physical barriers that prevent capillary action from causing warpage. The ledges are formed in advance to intercept underfill material before it can penetrate deeply between adjacent dice and induce substrate warpage during curing.
Solution Approach 2:
The ledges act as intermediary structures between the underfill material and the space between adjacent dice. By introducing these intermediate features on the dice surfaces, the patent creates a physical barrier that mediates the interaction between underfill material and the gap between dice, preventing direct capillary penetration that would cause warpage while still allowing underfill to provide structural support.
2Object-generated harmful factors
If multiple dicing procedures are used to form ledges, then underfill penetration is controlled and substrate warpage is reduced, but manufacturing process complexity increases
Solution Approach 1:
The dicing process is segmented into multiple stages: first dicing to separate individual dice, then selective removal of molding compound or additional dicing to form ledges on specific surfaces. This segmentation allows the complex ledge-forming operation to be broken down into manageable steps that can be integrated into existing manufacturing workflows, reducing the perceived complexity while achieving the warpage prevention benefit.
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 ledges control the extent of underfill material penetration, reducing substrate warpage and enhancing the structural integrity and reliability of semiconductor devices.
Implementation Method 1
capillary forces may draw the underfill material up between the adjacent dices to the surface of the dice
Data Source
AI summary
A die having a ledge along a sidewall, and a method of forming the die, is provided. A method of packaging the die is also provided. A substrate, such as a processed wafer, is diced by forming a first notch having a first width, and then forming a second notch within the first notch such that the second notch has a second width less than the first width. The second notch extends through the substrate, thereby dicing the substrate. The difference in widths between the first width and the second width results in a ledge along the sidewalls of the dice. The dice may be placed on a substrate, e.g., an interposer, and underfill placed between the dice and the substrate. The ledge prevents or reduces the distance the underfill is drawn up between adjacent dice. A molding compound may be formed over the substrate.