Ensuring Strength, Stability, and Performance of Thick & Thin Films
BONDING TECHNIQUES
LTS Research Laboratories, Inc. also provide bonding services to adhere the sputtering targets to the backing plates. Indium and Silver-Epoxy bonding agents are chosen as they provide high electrical and thermal conductivity, channeling heat and charge build-up away from the target. They also protect the target-backing plate interface from diffusion and alleviate stress caused by differing thermal expansion.
Significance of Bonding
Thermal and electrical conductivity
Durability and mechanical stability
Control of film properties
Uniform target wear
Reduction of stress and cracking
Choice of bonding materials
There are different bonding techniques employed by LTS, which vary depending on the material. Some of these bonding services are listed below:
LTS provides the complete suite of industrial bonding methods used for sputtering targets, semiconductor assemblies, and heat-sensitive components. This allows us to support metals, ceramics, composites, and refractory materials across both research and high-volume manufacturing.
A compliant, high-thermal-conductivity bond ideal for ceramic and low-conductivity targets. Indium accommodates differences in thermal expansion between the target and backing plate, reducing cracking during high-power operation.
A flexible, vacuum-compatible interface designed for temperature-sensitive targets, low-density ceramics, and materials that cannot tolerate rigid or high-temperature bonds. Elastomer bonds handle repeated cycling between vacuum and atmosphere without moisture absorption.
A solid-state metallic bond with exceptional strength, uniformity, and virtually zero void content. Suitable for high-demand semiconductor and production environments where thermal performance and mechanical stability are critical.
Bonding solutions engineered specifically for rotating cylindrical cathodes used in large-area coating, architectural glass, displays, and high-volume PVD systems.
Complete bonding and assembly for planar and rotary targets, including machining, bonding, inspection, re-bonding, and refurbishment services.
Precision, contamination-controlled bonding for critical components where bond uniformity, clean interfaces, and reliability are essential.
Cold bonding joins components without heat by using specialized adhesives that create a strong, uniform interface. It is an environmentally safe alternative when thermal exposure must be avoided. Cold bonding requires no special welding equipment, post-treatments, or elevated temperature processes. The adhesive fills surface voids, improves contact, and increases load-bearing capacity, making it suitable for heat-sensitive materials.
Diffusion bonding is a solid-state joining method in which two polished metallic surfaces are pressed together at high temperature and pressure. Their atoms diffuse into each other over time, forming a high-strength, porosity-free bond. This technique is widely used for refractory metals, aerospace components, and nuclear materials.
Materials commonly diffusion bonded include:
Titanium, Beryllium, Zirconium, Aluminum, Copper, Gold, Inconel, Nickel, Silver, Stainless Steel, and other high-purity metals.
Explosion bonding uses controlled detonation to force two metal surfaces together at high velocity, creating a metallurgical bond without melting. The explosive shock produces a jetting action that removes contaminants and forms a clean interface. This method is typically used for cladding carbon steel with corrosion-resistant alloys. It is limited to simple geometries such as plates and tube sheets and requires precise control to avoid brittle intermetallic formation or insufficient bonding energy.
PAS bonding is a rapid densification technique used for ceramics, oxides, nitrides, transparent materials, and compounds that cannot be processed using conventional sintering. A pulsed electric current is applied while the materials are heated under uniaxial pressure in a controlled vacuum chamber. The process achieves high density, strong bonding, and excellent reliability.
Indium is the most widely used sputtering-target bonding agent due to its high thermal conductivity and exceptional compliance. Its softness allows the target and backing plate to expand at different rates without inducing stress fractures. The main limitation is its low melting point of 156.6 °C; bonds weaken at temperatures above ~150 °C.
Silver-filled epoxy is ideal for bonding non-metallic targets to metal backing plates. It is extensively used for semiconductor devices, integrated circuits, diodes, transistors, and thin-film components. Silver epoxy provides good thermal conductivity and strong mechanical adhesion for non-metallic targets.
Elastomer bonding offers higher operational temperatures than indium and is preferred for low-melting-point targets and temperature-sensitive materials. It does not absorb moisture, remains stable through vacuum–air cycling, and provides a flexible, durable interface for brittle or porous targets.
