Semiconductor Lead Frame ESD Protection During Manufacturing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor chips are vulnerable to damage from electrostatic discharge (ESD) events during manufacturing, particularly during the water jet cleaning process, where high-pressure water can cause triboelectric charging and lead to burnt metallization and circuit damage.
Innovation Solution
Selected leads are electrically connected to the lead frame through metal strips and grounded throughout the manufacturing process to prevent ESD damage, with a test identifying susceptible leads and modifying the lead frame metallization to ensure these leads remain grounded until the final singulation step, where they are electrically isolated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If leads are electrically connected to the lead frame during manufacturing, then ESD protection is provided, but electrical isolation between individual leads is lost
Solution Approach 1:
The lead frame is segmented into individual lead units after the manufacturing process through singulation. During manufacturing, all leads remain connected to the grounded lead frame for ESD protection. After manufacturing, the lead frame is cut or separated to electrically isolate individual leads, eliminating harmful electrical interference while maintaining protection during the critical manufacturing phase.
Solution Approach 2:
ESD protection is established in advance by connecting all leads to the grounded lead frame before any manufacturing operations occur. This preliminary grounding ensures protection during water jet cleaning and other ESD-prone manufacturing steps. The electrical isolation is then applied as a subsequent action after manufacturing is complete.
2Reliability
If all leads are protected from ESD, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The lead frame serves multiple functions: it provides mechanical support for the semiconductor die, acts as a common electrical connection for all leads during manufacturing, and provides a grounding path for ESD protection. By making the lead frame itself the protection mechanism rather than adding separate protection structures to each lead, the solution achieves comprehensive ESD protection without increasing device complexity.
Solution Approach 2:
The lead frame automatically provides ESD protection to all leads through its inherent grounding connection. No additional active components or complex control systems are needed - the lead frame's natural electrical connection to ground during manufacturing processes provides the protection. This self-service approach eliminates the need for complex external protection circuits.
3Ease of manufacture
If water jet cleaning is used during manufacturing, then cleaning effectiveness is improved, but triboelectric charging and ESD damage occur
Solution Approach 1:
Before the water jet cleaning process occurs, all leads are pre-connected to the grounded lead frame. This preliminary grounding creates a safe electrical path that prevents triboelectric charging from causing ESD damage. The anti-action (grounding) is established before the harmful process (water jet cleaning) begins, neutralizing the potential damage.
Solution Approach 2:
The lead frame acts as an intermediary between the water jet cleaning process and the semiconductor leads. During water jet cleaning, the lead frame absorbs and dissipates triboelectric charges through its grounding connection, preventing direct charge accumulation on the sensitive leads. The lead frame mediates the interaction between the cleaning process and the protected leads.
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 method effectively protects leads from ESD events, preventing damage and ensuring reliable chip production by maintaining electrical connection to ground until the chips are packaged and ready for shipping, while also simplifying the manufacturing process by only protecting necessary leads.
Implementation Method 1
Semiconductor chips are susceptible to damage from electrostatic discharge. The lead frame remains as a single piece array during the entire manufacturing process, and at the end of the manufacturing process is singulated into individual packaged chips. It is important to protect each lead against and ESD event during the manufacturing process
Implementation Method 2
During the manufacturing process, the semiconductor chip is connected to a lead frame. Electrostatic discharge can occur at various times during the handling of the semiconductor chip, both during the manufacture and after the manufacture of the chip. During the manufacturing process, the semiconductor chip is connected to a lead frame
Implementation Method 3
Selected leads are electrically connected through metal strips to the lead frame until the end of the manufacturing process. The lead frame is grounded through the manufacturing process to prevent any ESD event from causing damage to the protected leads
Implementation Method 4
In the final singulation step, the leads are electrically isolated from each other and from the lead frame, thus maintaining protection from a potential ESD event up until the final package singulation step. The sawing process removes the electrical connection each lead from the lead frame and, therefore, electrically isolates each lead from each other and also from the lead frame itself
Data Source
AI summary
According to principles of the disclosure as explained herein, selected leads are electrically connected through metal strips to the lead frame until the end of the manufacturing process. The lead frame is grounded through the manufacturing process to prevent any ESD event from causing damage to the protected leads. In the final singulation step, the leads are electrically isolated from each other and from the lead frame, thus maintaining protection from a potential ESD event up until the final package singulation step.