Drift Tube Assembly Interference Fit for Alignment and Cooling

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Solution Overview

Problem

Conventional mechanical fasteners in drift tube assemblies of high-energy ion implanters provide weak connections, leading to misalignment and poor thermal coupling, compromising the precision and cooling efficiency of the electrodes.

Innovation Solution

A drift tube assembly is assembled using an interference fit between conductive drift tubes, insulating rods, and a mounting bracket, achieved through thermal shrink fitting, eliminating the need for mechanical fasteners and enhancing thermal conductivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If mechanical fasteners are used to connect drift tubes to insulating rods and mounting brackets, then the assembly process is simple and straightforward, but the connection strength is insufficient to resist external forces that can twist or translate the drift tubes out of their nominal precise positions and orientations

Engineering Contradiction:

Improveconnection strengthVSAvoiddrift tube position and orientation precision

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces mechanical fasteners (screws, pins, friction washers) with a thermal interference fit system. The insulating rods are heated to expand their dimensions, inserted into the drift tubes and mounting brackets, then cooled to create a tight interference fit that provides both strong mechanical connection and precise positioning without traditional fasteners.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes thermal expansion and contraction of the insulating rods to achieve the interference fit. The rods are heated to expand beyond their nominal dimensions for insertion, then cooled to contract and create a tight, precise, and strong connection between the drift tubes and mounting brackets, eliminating the need for mechanical fasteners.

Inventive Principle:

Principle #37Thermal expansion

2Temperature

If mechanical fasteners are used to connect drift tubes to insulating rods and mounting brackets, then the assembly process is straightforward, but the thermal coupling between the drift tubes, insulating rods, and mounting bracket is weak, compromising cooling of the electrodes

Engineering Contradiction:

Improvethermal coupling efficiencyVSAvoidassembly process complexity

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical fasteners with a thermal interference fit system that simultaneously provides both mechanical connection and thermal coupling. The direct contact created by the interference fit between the insulating rods and the drift tubes/mounting brackets establishes efficient thermal pathways for cooling, eliminating the thermal gaps that would exist with mechanical fasteners.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The thermal expansion process creates a tight interference fit that ensures optimal thermal contact between components. As the insulating rods cool and contract, they create strong thermal coupling with the drift tubes and mounting brackets, enabling efficient heat transfer for electrode cooling while the assembly process remains relatively simple.

Inventive Principle:

Principle #37Thermal expansion

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 assembly provides strong, precise connections resistant to external forces and improved thermal conductivity, maintaining the drift tubes' alignment and cooling efficiency.

Implementation Method 1

heating the first drift tube and the second drift tube, inserting a first end of the first insulating rod into a mounting hole of the first drift tube and inserting a first end of the second insulating rod into a mounting hole of the second drift tube, cooling the first drift tube and the second drift tube to produce an interference fit

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

heating the mounting bracket, inserting a second end of the first insulating rod into a first mounting hole of the mounting bracket and inserting a second end of the second insulating rod into a second mounting hole of the mounting bracket, and cooling the mounting bracket to produce an interference fit

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentUS12431329B2Method of assembling drift tube assemblies in ion implantors

Publication Date: 2025.09.30 APPLIED MATERIALS INC

AI summary

An ion implantation system including an ion source for generating an ion beam, an end station for holding a substrate to be implanted by the ion beam, and a linear accelerator disposed between the ion source and the end station and adapted to accelerate the ion beam, the linear accelerator comprising at least one acceleration stage including a resonator coil coupled to a drift tube assembly, the drift tube assembly including a first drift tube coupled to a first end of a first insulting rod via interference fit, a second drift tube coupled to a first end of a second insulting rod via interference fit, and a mounting bracket coupled to a second end of the first insulting rod and to a second end of the second insulting rod via interference fit.