Semiconductor Side Terminal Height Variation for Solder Fillet Reliability

Solution Overview

Problem

Conventional semiconductor devices with side terminals face challenges in achieving sufficient mounting strength due to reduced terminal height and distance between through-vias and castellations, leading to unreliable solder connections and potential breakage of solder fillets during mounting on a substrate.

Innovation Solution

The semiconductor device incorporates higher second side terminals at corners of the package, formed in castellations or notches, to ensure the formation of larger solder fillets, even when miniaturized, by maintaining a sufficient distance from through-vias for appropriate strength and reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the distance between through-via and castellation is reduced to achieve miniaturization, then the device size is reduced, but the mounting strength deteriorates due to insufficient solder fillet formation

Engineering Contradiction:

Improvedevice sizeVSAvoidmounting strength

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by differentiating the height of side terminals based on their position. Corner side terminals are made higher than other side terminals to provide sufficient solder fillet formation space, while other terminals can be shorter. This localized differentiation resolves the contradiction by maintaining compact overall size while ensuring adequate mounting strength at critical corner positions.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces height as an additional dimensional variable to resolve the two-dimensional layout constraint. By varying the height of side terminals in the vertical dimension, the patent enables sufficient solder fillet formation without increasing the horizontal footprint, thus achieving miniaturization while maintaining mounting strength.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of manufacture

If conventional side terminal height is used, then manufacturing is simpler, but solder fillet formation is insufficient leading to unreliable mounting

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidmounting reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies local quality by differentiating the height of side terminals based on their position. Corner side terminals are made higher than other side terminals to provide sufficient solder fillet formation space, while other terminals can be shorter. This localized differentiation resolves the contradiction by maintaining compact overall size while ensuring adequate mounting strength at critical corner positions.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS7598611B2Semiconductor device with side terminals

Publication Date: 2009.10.06 PANASONIC SEMICON SOLUTIONS CO LTD

AI summary

Side terminals 3 at respective corners of a package are higher than side terminals 4 on each side of the package. Thus, even if the side terminals 4 on each side are lower than those according to the conventional art owing to miniaturization or the like, when a device is mounted on a mounting substrate by soldering, a solder fillet 11 of a sufficient size can be formed between each of the corner side terminals 3, which significantly affect reliability, and a corresponding terminal on the mounting substrate. Thus, the device can be more reliably mounted on the mounting substrate by soldering.