If you’re moving or relocating an ion implanter - particularly one that’s been in use for an extended period - it’s absolutely critical that you consider decontamination in your project plan.
Over time, ion implanters accumulate layers of hazardous substances in the process chamber and related parts, such as arsenic, phosphorus and boron. It’s good practice to remove these hazards before dismantling the implanter in readiness for removal and shipping.
We’ve been decontaminating ion implanter tools for original equipment manufacturers (OEMs) and end-users in the semiconductor industry since 1991.
Here are our best practices for decontaminating an ion implanter safely, efficiently and effectively.
1. Thoroughly Plan for Decontamination
Decontaminating an ion implanter is not a matter of just cleaning it. Rather, it’s a meticulous process that requires careful planning and strict adherence to health and safety regulations throughout.
It’s also a highly dangerous and hazardous process that typically requires a three-person team, with a minimum of two engineers working together.
The first step in any decontamination process is to conduct a comprehensive risk assessment to establish which contaminants the implanter has been processing. This includes conducting a review of which types of process gasses may have been used (typically Arsenic, Boron and Phosphorous).
Next, ensure you have access to the necessary tools, materials and equipment to complete the decontamination safely and efficiently. These typically include:
- Personal protective equipment (PPE): Equip personnel with appropriate PPE, including respirators, chemical-resistant gloves, safety goggles and full-body protective suits. For higher-risk scenarios, such as dealing with volatile or toxic chemicals, consider specialist PPE like ventilated suits to provide additional protection.
- Specialised cleaning agents: Industry-approved solvents like acetone, isopropyl alcohol or hydrogen peroxide are effective for breaking down chemical residues and particles. Select cleaning agents that are compatible with both the process gasses used and the materials of the ion implanter’s components to avoid corrosion or surface damage.
- Equipment for decontamination & disassembly: Be mindful that tools must be completely free from contamination to avoid introducing new particles or residues during the decontamination and disassembly process. Lifting jibs with purpose-made attachments or similar are also required for moving heavy assemblies, for example, the implanter wheel, Accel column, pumps and similar parts.
- Containment Solutions: Containment solutions, such as spill trays, vacuum systems and sealed waste containers help capture hazardous materials safely. Additionally, proper disposal procedures should be in place for any waste generated during cleaning. That’s because hazardous materials require specialised handling and disposal in line with environmental regulations.
Follow our step-by-step process for relocating a large ion implanter. Read the case study here.
2. Clean the Components
Once you’ve verified that the system is fully powered down, has been disconnected and that the exhaust is left on and running, you can start removing process module (PM) assemblies and the immediate beamline path.
This is also where you’ll want to remove and replace consumables, typically including shielding, graphite components and o-rings. These assemblies are very delicate, and great care must be taken during removal.
Please note that components can be significantly large and heavy (some weigh over 100 kg) and can be situated in difficult-to-reach areas. So, it’s important that your teams exercise extreme caution when working with them to avoid injury or damage.
Liquid versions of toxic chemicals (such as Hydrofluoric acid) may also be present in cryopump housings and exhaust tubes, so it goes without saying that your teams will need the right personal protective equipment (PPE) to protect them against harm.
At IES, we send all contaminated PM assemblies to our specialist lab for cleaning, ensuring we double-bag them and handle them with extreme care during transport. We recommend doing the same, unless you have in-house cleaning facilities.
Once you’ve removed all assemblies, you’ll be left with the contaminated chambers. It’s important to note that some of these areas may need the use of a toxic vacuum cleaner to clear any flaking before you start.
You’ll need to scrub the chambers by hand back to bare metal using a range of specialist materials. This is often an arduous task, but it’s necessary.
At IES, we’ll often use Deionized water (DI) and cleanroom cloths to bond to some of the materials. Then, we’ll use diamond-encrusted pads to scrub the chamber back to bare metal and polish with fine-scoring pads. We finish with a final wipe-down with DI and Isopropyl Alcohol (IPA).
It is extremely important to take great care not to damage the delicate o-ring groves during cleaning.
Finally, you’ll need to perform area testing to ensure decontamination residue levels are within specified and industry-safe limits (you’ll never be able to eliminate all the particles entirely). To do this, saturate several 100x100mm areas with DI and perform swipe tests. Send the test papers to an accredited lab to confirm residue levels.
3. Reassembly
Once you’ve confirmed that residue levels are within safe limits, and the PM assemblies have returned from cleaning, you can begin replacing the clean assemblies and start the chamber and beamline rebuild.
Be sure to follow OEM assembly guidelines (which typically outline specific torque values, sequencing for component installation, and new or cleaned consumables) and take measures to avoid reintroducing contaminants into the system.
These measures include following cleanroom protocols, maintaining a clean work area and using clean tools to avoid cross-contamination.
Decontaminate an Ion Implanter with Total Confidence
We’ve been decontaminating ion implanter tools for original equipment manufacturers (OEMs) and end-users in the semiconductor industry since 1991.
Our turnkey service covers every step of your semiconductor decontamination, relocation, start-up and commission.
Head to our service page to discover how we can support your project.
