RF Shielding for Singulated Semiconductor Packages
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Solution Overview
Problem
Current methods for RF shielding of semiconductor device packages are inefficient due to a narrow process window in cutting copper traces and require partial singulation, making it costly and time-consuming to achieve full shielding of an array of packages.
Innovation Solution
A method involving block molding and single-unit molding processes to apply a conductive shield that makes electrical contact with exposed conducting pads and ground traces, allowing for effective RF shielding of singulated packages with a wider process window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cutting is used to expose copper traces for shield connection, then electrical contact is achieved, but the process window becomes narrow and manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by forming protruding portions of the conductive shield during the molding process itself, before any cutting operations. The mold design includes protrusions that directly create corresponding protruding portions on the shield, which then make contact with the copper traces. This eliminates the need for subsequent cutting to expose traces, as the contact structure is already prepared in advance.
Solution Approach 2:
The patent introduces an intermediary element - the protruding portions of the conductive shield - that mediates between the shield and the copper traces. Instead of directly cutting into the substrate to create contact, the protruding portions act as intermediaries that make contact with the traces, thereby avoiding the need for complex cutting operations while ensuring reliable electrical connection.
2Reliability
If packages are singulated before shielding, then individual package shielding is achieved, but productivity decreases and costs increase
Solution Approach 1:
The patent merges multiple operations into a single integrated process. Packages are molded in an array format on a support substrate, and the conductive shield is applied to multiple packages simultaneously while they remain connected. The protruding portions of the shields make contact with traces on the support substrate, enabling batch processing rather than individual package treatment, thereby significantly improving productivity.
Solution Approach 2:
The support substrate serves multiple functions: it holds the packages in array during molding, provides the copper traces for electrical connection, and acts as the base for applying the conductive shield to multiple packages simultaneously. This multi-functional design enables batch processing while maintaining shielding effectiveness for each individual package.
3Object-affected harmful factors
If conventional shielding methods are used, then RF shielding is achieved, but manufacturing time and cost increase due to narrow process window
Solution Approach 1:
The mold design incorporates protrusions that create corresponding protruding portions on the conductive shield during the molding process itself. This preliminary formation of contact structures eliminates the need for subsequent cutting and tracing operations, significantly reducing manufacturing cycle time while ensuring reliable RF shielding through proper electrical contact with the copper traces.
Solution Approach 2:
The patent combines multiple manufacturing operations into a single integrated process: molding the packages with integrated protruding shield portions, applying the conductive shield to multiple packages in array simultaneously, and establishing electrical contacts with the copper traces on the support substrate. This merged process reduces the number of discrete steps and overall manufacturing time while maintaining effective RF shielding.
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 method provides comprehensive RF shielding for semiconductor device packages by ensuring electrical contact with ground traces, enhancing manufacturing efficiency and reducing costs by allowing shielding of an array of packages simultaneously.
Implementation Method 1
The conductive shield covering the device makes electrical contact with the ground trace, thereby providing RF shielding for the device
Data Source
AI summary
A method for manufacturing a semiconductor device package to provide RF shielding. The device is mounted on a laminated substrate having conducting pads on its top surface. A molding compound covers the substrate top surface and encapsulates the devices. The substrate is disposed on a tape; the molding compound and the substrate are cut through, forming package units separated by the saw cut width and exposing a portion of a conducting pad. In an embodiment, the tape is stretched to widen the gap between package units. A conductive shield is applied to cover each package unit and to make electrical contact with the exposed conducting pad portion, thereby connecting to a ground trace beneath the device and providing RF shielding for the device. A single-unit molding process may be used, in which the conducting pad is exposed during and after molding.