Semi-Finished Package With Peripheral Protrusions To Prevent Warpage
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Solution Overview
Problem
Conventional semi-finished packages experience warpage due to differing coefficients of thermal expansion between the carrier, molding compound, and chips, leading to manufacturing issues such as sticking, failed laser marking, and missing solder balls, especially as packages become smaller and lighter.
Innovation Solution
A semi-finished package design featuring a carrier with a molding compound having outer protrusions at the periphery, where the height of these protrusions is greater than the body, which increases rigidity and addresses warpage by incorporating a cutting process to remove the protrusions, thereby enhancing the yield rate of package units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the carrier and molding compound are made thinner to reduce package weight and size, then the package weight and size are reduced, but the warpage becomes more serious
Solution Approach 1:
The patent applies preliminary action by forming protrusions on the molding compound before the cutting process. These protrusions are created in advance to provide structural support and prevent warpage during subsequent handling and cutting operations. The protrusions act as reinforcement elements that maintain package stability even when the overall package thickness is reduced.
Solution Approach 2:
The patent applies local quality by adding protrusions only at specific locations on the molding compound rather than uniformly thickening the entire structure. The protrusions are positioned at the periphery of the package where they provide maximum structural support for handling and cutting, while keeping the overall package thin and lightweight. This localized reinforcement solves the warpage problem without compromising the lightweight design.
2Reliability
If the molding compound is melted at high temperature to encapsulate chips, then the encapsulation is achieved, but the warpage occurs due to different coefficients of thermal expansion
Solution Approach 1:
The patent applies parameter changes by modifying the geometric parameters of the molding compound structure. By adding protrusions with specific dimensions (height greater than the body thickness), the structural parameters are changed to compensate for the thermal expansion differences. This geometric modification helps maintain dimensional stability after high-temperature encapsulation processes.
3Ease of manufacture
If slots are disposed over the chips in the molding compound, then the molding process is simplified, but the appearance is affected and yield rate decreases
Solution Approach 1:
The patent applies the taking out principle by removing the problematic slots from the molding compound structure. Instead of having slots that affect appearance and cause sticking issues, the design uses a solid molding compound body with peripheral protrusions. This extraction of the harmful feature (slots) eliminates the appearance problems and manufacturing defects while maintaining the encapsulation function.
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 increased rigidity of the package units improves handling and reduces warpage issues, leading to higher yield rates and improved manufacturing outcomes by maintaining coplanarity and preventing solder ball defects.
Implementation Method 1
The carrier 11 and the chips 12 expand during the heating process, so that the carrier 11, the molding compound 13 and the chips 12 are combined under high temperature
Implementation Method 2
the molding compound 13 of the first conventional semi-finished package 1 is melted after heating, so as to encapsulate the chips 12
Data Source
AI summary
The present invention relates to a semi-finished package and a method for making a package. The semi-finished package includes a carrier and at least one molding compound. The molding compound is disposed on a surface of the carrier, and has a body and a plurality of outer protrusions. The outer protrusions are disposed at the periphery of the body, and the height of the outer protrusions is greater than that of the body. Thus, by utilizing the outer protrusions, the rigidity of the semi-finished package is increased, so as to overcome the warpage of the semi-finished package caused by different coefficients of thermal expansion of the molding compound and the carrier. Therefore, the yield rate of the package unit is increased.