Sputtering Targets: Backing Plates & Bonding
Sputtering targets are materials used in the sputtering processes to deposit thin films on the surfaces of a wide variety of materials.
Common applications of sputtering targets include:
- Semiconductor manufacturing
- Optical coatings
- Decorative coatings
- Hard coatings
- Corrosion protection
- Biomedical coatings
Sustainability is a top priority and PI-KEM offers de-bonding, cleaning and refurbishment services to extend the lifetime of your backing plates, thereby reducing waste and costs.
Whether due to the equipment being used, the need to strengthen the target or to reduce the cost of purchasing a thicker target, PI-KEM can provide a comprehensive target bonding service. We can source standard shaped backing plates or customise them to your needs, or customers can provide their own plates. We also offer a consignment stock option for backing plates to ensure quick turnaround for bonding.
PI-KEM is proud to be your one-stop partner for high-quality thin film deposition products and services.
Backing Plates
- Support the target
- Provide a heat sink during the sputtering process
- Preventing melting and deforming.
Backing plates are generally made of materials that are inert to the target material and have high thermal conductivity. This protects the target from damage due to melting or deforming during the sputtering process and extends its working life.
Backing plates are usually made of:
- Aluminium
- Copper
- Molybdenum
- Stainless steel
The backing plate material is selected based on the sputtering target material and application. For example:
- Aluminium is a good choice for backing planar targets because it is lightweight and has good thermal conductivity
- Stainless steel is a good choice for cylindrical targets backing plates because it is strong and has good corrosion resistance
- Molybdenum is used as it has a lower thermal expansion and can be used with brittle materials, for example ceramics
PI-KEM can also provide monoblock targets where the backing plate and target are made from one material. This can be a more economical options for materials including copper, titanium, and aluminium as there is more material utilisation and less risk of debonding or contamination.
Bonding
Bonding is the process of attaching a sputtering target to a backing plate.
Key considerations for bonding are:
- The bond must be strong enough to withstand the high temperatures and forces generated during the sputtering process
- The bonding method is dependent on the type of sputtering target and backing plate. For planar targets, an epoxy adhesive is typically used to attach the target to the backing plate. For cylindrical targets, a brazing alloy is often used. For rotating targets, the target is typically bonded to the backing plate using a welding process.
The reliability of the bond between a sputtering target and backing plate is essential to ensure optimised performance. PI-KEM’s bonding services include indium, elastomer, and epoxy bonding.
Indium
- Best thermal conductivity of all available bonds
- Most materials can be indium bonded but there are a few exceptions
Elastomer- Higher temperature capability over indium bond
- Recommended when customers consistently melt indium bonds
- Ideal for low melting point target materials, temperature sensitive compounds, low density, or fragile targets
- Does not absorb any moisture and is more than suitable to handle cycles between vacuum and atmosphere
Epoxy- Economical, depending on application
- Thermal and electrical conductivity
Benefits
- Avoids damage to targets through inadequate cooling
- Prolongs working life of target over a non-bonded target
- Potential to achieve faster sputtering rates when using high power input
- Consistently repeat thin film process parameters
- Cost-effective as reduces thickness of sputtering target
- Enables the use of specialised or custom designed backing plates to suit any coating machine
Service Overview
Backing Plate Material:
- Aluminium
- Copper
- Molybdenum
- Stainless steel
Format:
- Planar
- Cylindrical
- Monoblock
- Tiled
Additional services:
- Full sputter target sales service
- Precious metal reclaim
- Backing Plate refurbishment
- Sputtering target consignment stock options available, for quick turnaround on rebonded targets
