Wire Bonder Transducer Mounting for Multi-Axis Scrubbing

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Solution Overview

Problem

Conventional wire bonders have limitations in cleaning the die pad surface during ball bonding due to a linear scrubbing motion and fixed ultrasonic frequency, which can compromise the quality and strength of the ball bond with the die pad surface.

Innovation Solution

An apparatus with a flexural structure and piezo-stack actuators is used to mount the transducer on a wire bonder, allowing for a multi-linear scrubbing motion and varying frequencies, enabling better cleaning and bonding energy distribution along different axes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a linear scrubbing motion is used during ball bonding, then the bonding device structure is simple, but the cleaning quality of the die pad surface is insufficient

Engineering Contradiction:
Improvecleaning quality of die pad surfaceVSAvoidbonding device structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by replacing the static linear scrubbing motion with a dynamic multi-linear scrubbing motion. The flexural structure enables the bonding tool tip to move in multiple linear directions (X, Y, and Z axes) during the bonding process, creating a more effective cleaning action on the die pad surface while maintaining a relatively simple overall device structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements the dimensionality change principle by adding movement in multiple spatial dimensions. Instead of restricting the scrubbing motion to a single linear path, the flexural structure allows the bonding tool tip to scrub across the die pad surface in multiple linear directions, effectively utilizing X, Y, and Z axes to improve cleaning coverage and quality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If a fixed ultrasonic frequency is used during bonding, then the transducer operation is simple, but the bond strength between ball bond and die pad surface is compromised

Engineering Contradiction:
Improvebond strength between ball bond and die pad surfaceVSAvoidtransducer operation
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by enabling the transducer to operate at variable frequencies rather than a fixed frequency. The system can dynamically adjust the ultrasonic frequency and combine it with multi-linear mechanical motion to optimize bonding conditions, resulting in improved bond strength between the ball bond and die pad surface.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements the parameter changes principle by allowing variation in the ultrasonic frequency parameter during the bonding process. Instead of operating at a single fixed frequency, the system can change the frequency parameter to match different bonding requirements and material properties, thereby optimizing the bond strength while managing transducer operation complexity.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If a single linear scrubbing path is used, then the device control is simple, but the cleaning effectiveness on the die pad surface is insufficient

Engineering Contradiction:
Improvecleaning effectiveness of die pad surfaceVSAvoiddevice control
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The patent applies the dynamics principle by transforming the static single linear scrubbing path into a dynamic multi-linear scrubbing path. The flexural structure enables automatic multi-axis movement of the bonding tool tip, improving cleaning effectiveness across the die pad surface while the system manages the operational complexity through integrated control mechanisms.

Inventive Principle:
Principle #15Dynamics

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 approach improves the quality of the ball bonding process by ensuring a thorough cleaning of the die pad surface and enhances the bond strength between the ball bond and the die pad surface.

Implementation Method 1

the at least one actuator may be a piezo-stack actuator that is configured to be actuated by an electrical source oscillating at a sub-ultrasonic frequency

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

an ultrasonic transducer of a wire bonder is mechanically driven to move the bonding tool tip in a scrubbing motion during ball bonding to clean a die pad surface of a semiconductor die. The ultrasonic transducer also provides ultrasonic bonding energy during ball bonding to cause adhesion of a ball bond of the bonding wire with the die pad surface

Methodology Applied
Scientific EffectUltrasonic vibration: Ultrasonic Vibration

Data Source

PatentUS8919631B2Wire bonder including a transducer, a bond head, and a mounting apparatus
Publication Date: 2014.12.30 ASMPT SINGAPORE PTE LTD
  • US8919631B2 patent drawing
  • US8919631B2 patent drawing
  • US8919631B2 patent drawing

AI summary

Disclosed is an apparatus for mounting a transducer to a bond head of a wire bonder. In particular, the bond head of the wire bonder is operative to mechanically drive the transducer when forming electrical interconnections between separate locations within a semiconductor package. Specifically, the apparatus comprises: i) a flexural structure having a connector for connecting to the transducer, the flexural structure being configured to bend; and ii) at least one actuator attached to the flexural structure, the at least one actuator being operative to bend the flexural structure to thereby cause a displacement of the transducer connected thereto via the connector.