Lead Frame Terminal Recesses to Contain Dicing Burrs

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Solution Overview

Problem

The existing semiconductor device manufacturing process often results in burrs during the dicing step, leading to increased gaps between the semiconductor device and the module substrate, which can affect the flatness and bonding quality, and complicate solder formation and inspection.

Innovation Solution

Incorporating a recessed portion between the back-side and lateral-side portions of the terminal, which reduces the protrusion of burrs during the half-cutting process, allowing for improved flatness and bonding with the module substrate, and facilitating better solder formation and inspection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If dicing is performed to separate semiconductor devices, then productivity is improved, but burrs are generated on the lead frame terminals

Engineering Contradiction:

Improvedevice separation efficiencyVSAvoidterminal surface quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

A recessed portion is formed in advance at the position where burrs are likely to occur on the terminal before the dicing process. This preliminary structural modification allows burrs generated during dicing to be contained within the recessed portion, preventing them from affecting the functional surfaces of the terminal.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of attempting to completely prevent burr formation during dicing, the invention accepts burr generation as inevitable but converts the harmful effect by providing a recessed portion that captures and isolates the burrs, transforming them from defects that affect functionality into contained features that do not interfere with device performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Ease of manufacture

If burrs are present on terminals, then manufacturing is simplified, but bonding quality with module substrate deteriorates

Engineering Contradiction:

Improvedicing process simplicityVSAvoidbonding quality

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The recessed portion is formed beforehand at the terminal position to anticipate and accommodate burr formation. This allows the dicing process to proceed without special precautions while ensuring that any burrs generated will be contained within the pre-formed recessed portion, preserving bonding quality.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention transforms the harmful effect of burrs on bonding quality by providing a recessed portion that isolates burrs from the bonding interface. The burrs remain on the terminal but are confined within the recessed portion, preventing them from interfering with solder formation and bonding between the terminal and module substrate.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Device complexity

If burrs protrude from terminal surface, then device structure remains simple, but inspection precision deteriorates

Engineering Contradiction:

Improveterminal structureVSAvoidinspection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

A recessed portion is formed in advance at the terminal position to anticipate burr formation. This simple structural addition provides a designated space for burrs, preventing them from protruding into areas that would interfere with inspection processes and maintain high measurement precision.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The recessed portion transforms burrs from inspection-obstructing protrusions into contained features. By providing a dedicated recessed space, burrs are isolated from the inspection field, allowing automated optical inspection and other measurement processes to proceed with high accuracy without being affected by the presence of burrs.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

4Ease of manufacture

If no recessed portion is provided, then manufacturing process is simpler, but gaps between device and substrate increase

Engineering Contradiction:

Improveprocess complexityVSAvoidgap distance

Core Design Contradiction:

Ease of manufactureVSLength of stationary object

Solution Approach 1:

A recessed portion is formed in advance at the terminal position to anticipate and accommodate burr formation. This prevents burrs from creating gaps between the device and module substrate, maintaining proper spacing and bonding without adding significant complexity to the manufacturing process.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS20230307349A1Semiconductor device and method for manufacturing the same

Publication Date: 2023.09.28 KK TOSHIBA

AI summary

According to one embodiment, a semiconductor device includes a lead frame including a terminal; an element on a first surface of the lead frame; and a package member covering the lead frame and the semiconductor element. The terminal includes a back-side portion provided on a side of a second surface of the lead frame and exposed from the package member in a first direction perpendicular to the first surface, the second surface being opposite to the first surface, a lateral-side portion provided between the first surface and the back-side portion in the first direction and exposed from the package member in a second direction parallel to the first surface, and a recessed portion provided between the lateral-side portion and the back-side portion in the first direction.