Semiconductor Substrate Warpage Control via Pre-heating
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Solution Overview
Problem
The miniaturization of semiconductor devices leads to increased complexity in manufacturing due to the combination of various materials with different thermal properties, resulting in warpage issues during thermal processes, which can cause electrical connectivity failures.
Innovation Solution
A method of manufacturing semiconductor structures involves using a molding member with a curved surface or at a temperature higher than the molding temperature to encapsulate a chip, allowing for the reduction or elimination of substrate curvature through cross-linking reactions and temperature adjustments, thereby maintaining a flat configuration and preventing warpage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If wafer level chip scale packaging (WLCSP) is used for miniaturized semiconductor devices, then device size is reduced and functionality is increased, but manufacturing complexity increases due to combination of various materials with different thermal properties
Solution Approach 1:
The substrate is pre-heated to a temperature higher than the molding temperature before the molding process. This preliminary thermal action prepares the substrate to compensate for warpage that would otherwise occur during the subsequent molding process, allowing the substrate to return to a flat state after cooling and molding completion.
Solution Approach 2:
The temperature of the substrate is changed from a higher pre-heating temperature to the molding temperature during the molding process. This parameter change enables the substrate to undergo thermal expansion/contraction that compensates for warpage, maintaining flatness throughout the manufacturing process despite the complexity of combining multiple materials with different thermal properties.
2Adaptability or versatility
If multiple materials with different thermal properties are combined in semiconductor devices, then device functionality and integration are improved, but warpage issues occur during thermal processes
Solution Approach 1:
The substrate is heated to a temperature higher than the molding temperature, causing thermal expansion. This expansion compensates for the warpage that would occur when multiple materials with different thermal expansion coefficients are combined during the molding process. The substrate's thermal response is utilized to maintain flatness despite the heterogeneous material composition.
Solution Approach 2:
The substrate is pre-heated to counteract the warpage force that will occur during molding. This preliminary anti-action creates an initial curvature opposite to the expected warpage, so that when the molding process occurs, the substrate returns to a flat state, preventing connectivity failures.
3Ease of manufacture
If substrate curvature is not controlled during molding, then manufacturing process is simpler, but electrical connectivity failures occur due to warpage
Solution Approach 1:
The substrate is pre-heated before molding to establish the correct curvature state. This preliminary action ensures that the substrate will be flat after the molding process, preventing electrical connectivity failures while maintaining a relatively simple molding process without requiring complex real-time curvature control mechanisms.
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 improves the reliability of semiconductor structures by ensuring proper electrical connectivity and reducing the risk of cold joints by maintaining the substrate in a flat configuration post-molding, compensating for size reductions in both the substrate and molding.
Implementation Method 1
providing a first molding member at a first temperature; disposing the substrate over the first molding member... wherein the first temperature is substantially higher than the molding temperature
Implementation Method 2
the formation of the molding involves a cross-linking reaction
Data Source
AI summary
A semiconductor structure includes a substrate; a chip disposed over the substrate; and a molding disposed over the substrate and surrounding the chip at a molding temperature. The warpage of the substrate is convex or about zero at the molding temperature or 10° C. more or less than the molding temperature.