Category Archives: Technical

Innovation in Chemical Etching – 5 Areas to Expect Growth

Chemical etching ties into many different industries. Automotive, aerospace, medical, semiconductor solar, electronics, and many more industries produce products by chemical etching. You are probably using something that was produced by chemical etching right now. This is why the photochemical machining (PCM) industry is so versatile. Whenever this industry innovates and grows, so does the technology it feeds into. In the 1950s, chemical etching revolutionized printed circuit boards by providing an efficient, economical method to produce reliable electronics. How could chemical etching revolutionize technology again, and what changes should we expect in chemical etching? In this article, we will talk about the 5 areas in chemical etching where we can expect innovation.


1. Process Simplification

There is always room for improvement when it comes to simplifying process equipment. The more accessible the equipment becomes; the less hassle preventive maintenance and operation becomes. Etching can be a simple process, but when you are using it to commercially produce parts or circuits, more constraints and challenges come along and lead to more complex systems. A simplistic design that gets the job done can go a long way.


2. High Resolution

Obtaining higher resolution means being able to produce more precise and complex designs. With etching finer features, comes the challenges of consistently meeting narrow tolerances. Many of the limiting factors to high-resolution etching occur prior to the etching process.  It is critical that items such as proper artwork compensation, thickness and consistency of photo-resist application, precise alignment of the top and bottom side artwork, and the resolution and capability of the imaging equipment all be optimized to achieve high-resolution etch results. Even something as small as a speck of dust can result in a reduction of the resolution of the etched part. Clean rooms rated class 10,000 or better are required.


3. Undercut

With the trend of designs becoming more complex and packed together, Undercut has become an issue that limits resolution as you increase etch depth. If undercut was completely eliminated, you could theoretically obtain a feature of any size with any etch depth. The main problem with undercut is that it is desirable to have a fast etch rate to maximize production. However, the typical trend is that whatever results in higher etch rates, also results in more undercut.

Some etchants have been used to try to reduce sidewall etching by forming a complex with the sidewalls, but it still has not gotten rid of the issue of undercut. Sidewall etching can also be reduced by controlling the crystalline structure of the metal. Controlling this is aspect however can be an expensive and challenging process. In the near future, It is entirely possible a new form of etchant or method to control crystalline structure can come about to efficiently reduce undercut.


4. Etch Uniformity

Etch uniformity is also another area in chemical etching that can cause growth. As manufacturers try to maximize production, there will be a shift towards using larger panels to get more parts per panel. However the larger the panel, the harder it is to maintain a uniform etch. This difficulty in etch uniformity comes from what is called “The Puddle Effect”.

Diagram of "The Puddle Effect" on a panel.

This effect describes the lack of diffusion on the surface of the panel due to the formation of a puddle in the middle. The puddle inhibits a uniform reaction by creating a barrier between the fresh etchant and the surface. Because of The Puddle Effect, the edges of panels etch faster than the middle. This tends to be less of a problem in chemical milling because you etch through. Uniformity in the printed circuit board industry, however, can more challenging to achieve.

There have been many attempts to overcome this problem, but the best solution currently is “intermittent spray”. This is a solution developed by Chemcut to overcome the deviation caused by The Puddle Effect. It is considered the best because it minimizes deviation without any loss in production rate, transport capabilities, and equipment simplicity. Intermittent spray achieves this by creating a targeted etch in the middle of the panel to compensate for the difference on edges.


5. Thin Material Transport

In the printed circuit board industry, there is always a drive to obtain thinner, flexible material.

Transporting thin material is a challenge in chemical etching. This is because the panels need enough open space to be sprayed with the etchant. The downside here is that when there is open space, there is a chance for the leading edges to deviate and cause wrinkles and folds. There is a balance that needs to be met because as you fill the conveyor with transporting aids, you lose etching efficiency. That is because it becomes harder for the etchant to reach the surface. Not only do you lose efficiency, but you also have to worry about etch rates differing on the top and bottom.

A common approach to solving this problem is to attach a thicker board, known as a leader, to the leading edge of the thin material. This prevents the front end from getting caught anywhere in the line. The problem with this method is that it inhibits production rates and requires someone to manually attach and remove leaders. This is why many people in the chemical etching industry seek thin material transport systems that do not require leaders.

Due to the wide variety of thin materials and substrates that are currently available, it is not practical to rigidly define the thinnest material that etching equipment can transport without leaders.  A general guideline for minimum thickness is less than 1 mil (.001 inch, or 25 micron).  It is recommended that materials below this guideline be submitted to Chemcut for testing.  Perhaps in the near future etching equipment will be able to effortlessly transport even thinner material.


Conclusion

There are plenty of areas where we will likely see the photochemical machining industry flourish. A breakthrough on any of these 5 could be a big game-changer in technology because overcoming each one opens up new opportunities. At Chemcut we are always exploring new ways to improve the wet processing side of these areas. If you interested in what ways we are working to innovate wet processing, please feel free to send your questions here.

Preventive Maintenance – 4 Reasons Chemical Etchers Need it

Etcher opened for routine preventive maintenance.

4 Reasons Your Chemical Etching Plant Needs Preventive Maintenance

In our last post about chemical etching, we explored the 11 things you would need to start a chemical etching plant. In that article, the focus was on what equipment was going to be necessary to etch metal for any commercial purpose. Although the article covers most of your needs, it does not cover everything. Another thing that is highly important to your chemical etching plant is a preventive maintenance program.

Preventive maintenance (PM) is one of the most important and most ignored matters in chemical etching. The main purpose of a preventive maintenance program is to keep the equipment in peak operating condition. If it moves or interacts with chemicals, it will wear with time. Having a preventive maintenance program not only benefits you by keeping your equipment operable; it also improves production scheduling.  In this article, we will go over the 4 primary benefits of having a preventative maintenance program.


1. Machine Longevity

Having a successful chemical etching plant means more than just producing a lucrative product. It also means getting the most out of your equipment. Many Chemcut etchers have been in service for over 30 years, but that would have not been possible without preventive maintenance.

 Over time, machine parts will receive wear and tear. Even in the cleanest environments, housings and drive shafts will corrode. Conveyor wheels and rollers will eventually swell, become brittle, or loosen on the conveyor rod because of the chemistry. Taking care of your equipment means taking care of the parts that go into it. By doing this you can make parts last longer so they do not need to be replaced as frequently.


2. Increased safety

Since working in the chemical etching industry means working with chemicals that are highly corrosive and toxic, containment of those chemicals is highly important. To prevent unexpected events of exposure, it is important to perform inspections often. Always check seals, plumbing, and containment to ensure there is no compromise. In addition to preventive maintenance, you should use other safeguards like adequate ventilation, containment trays, and other types of engineering controls. No one should only rely on PPE.

To maintain adequate containment, keep an eye out for excessive crystal formation. Crystal formation is primarily a problem that comes from leaks or failing gaskets. They can also get in the way of creating a seal and lead to more drastic leaks over time.

Chemically compatible materials are key to safety too. Since the chemicals tend to damage materials over time, it is a good idea to keep an eye on your tubing and seals. Often the rubber-like materials become areas of attack, and some people may not be aware of the compatibility while replacing them. If an incompatible part is mistakenly used, it is good to catch it early before it fails.


3. Equipment Efficiency

Cleaning your equipment is a great form of preventive maintenance that can go a long way. Your etcher will be more efficient if all the nozzles, spray tubes, and filters are clean. If you are starting to under etch or your etch is no longer uniform, this is an indication that your nozzles need cleaning. Knowing when to clean your nozzles is clear, but knowing when to clean your filters and spray tubes is more difficult. Spray tube blockage and clogged-up filters will increase the load on the pumps. Signs of this could be the pumps heating up more than usual or unusual sounds while running.

Etcher spray nozzles that should be cleaned in preventive maintenance routine.
Without routine care, your etcher nozzles can become clogged and affect etch uniformity.

Cleaning is a major step because some metal etching processes can create by-products. If your etch line operates with a regeneration process to keep the etchant fresh, a by-product of the reactions could be a solid that will contaminate your bath. Often the contaminant from regeneration is salt, and if it is not cleared from the machine regularly, it will build-up and reduce your equipment’s efficiency.

When it comes to most processes in chemical etching, there are many variables that can directly affect the outcome of your product.  Since these factors can lead to bottlenecks and high scrap rates, it is recommended to frequently check the heating and cooling performance, calibrate the probes, and clean the nozzles.


4. Reliability

Cleaning and replacing worn-out parts regularly will increase your wet processing equipment’s longevity and reliability. Lack of PM will result in emergency maintenance and unexpected downtime which could prove to be expensive.  If a part were to break in the middle of a big project, your product may be late because of the time needed to diagnose the problem, receive the replacement part, perform the maintenance, and ensure the process is working again. This problem becomes magnified with more complicated pieces of equipment because of the unique parts and fine-tuning needed before continuing. By scheduling preventive maintenance around your big projects, you reduce the risk of downtime. If downtime does occur, it will not be as extreme as the case where maintenance was not been recently performed.


Conclusion

Having a preventive maintenance program will improve your chemical etching plant. With it, your equipment will be more long-lasting, safe, efficient, and reliable.

At Chemcut, we offer an extensive preventive maintenance agreement that is customer-specific.  This program could be annual, semi-annual, monthly, or whichever works best for you.  Chemcut would schedule a service technician to your facility to perform the preventive maintenance on the equipment, utilizing a PM check sheet as a guide.  Should you be interested in this type of service, please contact our service department by clicking here.

Chemical Etching – 11 Things You Need to Start a Chemical Etching Plant

11 Things You Need to Start a Chemical Etching Plant

Chemical etching has been around since 2500 BC and was primarily used for making jewelry. Etching is now used for making many different parts. It is used for making PCBs, flexible circuits, flexible heaters, metal screens, metal filters, glass products, semiconductors, solar panels, and much more.

If you are making parts from sheet metal, you need to seriously look at chemical etching. Sheet metal is perfect for the etching process and depending on your quantity can be the most economical process available.

This article was written so you can learn what is required to start a chemical etching plant and learn a little about each process required for etching metal. Chemical etching is also known as photo etching, photochemical etching, metal etching, and acid etching.


The 11 Things you need to start a chemical etching plant are:

  1. Inspection/Material Preparation
  2. Chemical cleaner
  3. Resist Application. Dry film laminator or liquid resist
  4. Exposure Unit
  5. Developer
  6. Etcher
  7. Stripper
  8. Inspection for Quality Control
  9. Waste Treatment
  10. A Facility
  11. Environmental Clearances

Keep reading to learn about each step and the approximate up-front investment needed for each process.


1. Inspection/Material Preparation (Non-Chemcut Product)

Inspection tools can vary depending on what exactly you are looking to etch. For inspection before etching, you are looking at tools to measure your material to make sure you have the correct size (Tape measure, calipers, and scales).

You may want a tool to check the material hardness if you have certain specs you need to stay within. There are so many inspection tools out there it really depends on what your shop needs. There is no one size fits all.

For preparation, you may need a cutting tool to cut the material to the correct size. If you are cutting a sheet of metal, you may want a deburr for the edges so you don’t cut your hands.

Once again, preparation tools are not a one size fits all. It will depend on what you are trying to etch.  

Approximate Cost = $75,000


2. Chemical Cleaner (Chemcut Product)

Chemical Cleaner

Chemical cleaning is a necessary process to ensure resist adheres to the metal properly. Without proper adhesion the resist will lift, and you will lose resolution.

In the world today that cannot happen. Everything is getting smaller and smaller so any resolution lost could completely ruin the part.

Most chemical cleaning processes have two steps. Starting with an alkaline clean which removes all oil/organics from the surface.

Then rinsed and cleaned again with acid which cleans the rest of the contaminants off the surface. The acid clean also micro etches the surface which adds roughness to the surface.

The rougher surface allows for better resist adhesion.

Depending on your product and how tight your specs are there are other cleaners available. They include scrubber, deburr, electrolytic cleaner, and ultrasonic cleaner.

Approximate Cost = $150,000


3. Resist Application (Non-Chemcut Product)

Resist applier

Applying resist is a relatively easy process. The key point to focus on with resist is to talk with your supplier and make sure you select the resist best suited for your application.

Certain resist is designed to work best with copper, steel, glass, and so on. So, make sure to match your resist with your metal/ceramic.

Once you determine your material and the resist type that matches it. You need to look at the resolution each resist offers.

Typically, thinner resists offer better resolution because it allows the etchant to get in and out of the channel easier.

Liquid resists are thinner and offer greater resolution, but the application process is more difficult than dry film.

Approximate Cost = $40,000


4. Exposure Unit (Non-Chemcut Product)

As everything keeps getting smaller this has become one of the most important steps. A speck of dirt is enough to cause an open circuit on fine lines. The slightest misalignment on artwork top to bottom has the potential to shift dimensions outside the tolerances.

There are many different exposure units on the market now. Most do a very good job, but there are a few things that are important to have to make sure you can etch fine features.

Those features are collimated light (or LDI) and features that help create near perfect alignment. You will also need a yellow room. Keeping the yellow room and material clean will help you significantly.

The last tip we have is to hold the panel for 30 minutes after exposing it so the resist can lock into the metal more before developing it.

Approximate Cost = $200,000


5. Developer (Chemcut Product)

Photoresist developer
OLYMPUS DIGITAL CAMERA

The developer is used to dissolve the photoresist that was not exposed to the UV light in the above step. Removing the unpolymerized resist exposes the metal you would like to etch away. This provides you with the design you want to etch into your material.  

Developing is normally looked at as less critical than etching. This is true, BUT it doesn’t mean you can overlook the developing step. The photoresist can be underdeveloped or overdeveloped.

Underdeveloped means all the unpolymerized resist was not completely removed. So, you did not fully expose the metal that you want to etch away. This results in smaller holes or no breakthrough for chemical milling and shorts for circuits.

Overdeveloped means, the developing solution started to undercut the resist. This means the resist may lift while etching which means you are losing resolution and worse etch away the metal you want to keep.

For chemical machining, you may end up outside your tolerances and for circuits, you may end up with open circuits.

Approximate Cost = $92,000


6. Etcher (Chemcut Product)

Chemical Etcher

The etcher is where the metal removal happens and is the most critical piece of wet processing equipment. Like photoresists, the chemistry used in the etcher needs to be matched with the metal you want to etch.

What is so critical about the etcher?

The etch uniformity is first and foremost. To have great etch uniformity you need to have the solution moving. If the solution sits on one spot for too long the solution becomes less or non-reactive.

This causes poor etch uniformity. This is known as the puddle effect.

Secondly, transport is important. Most material thickness has no issue in the developer because all the metal is there, and the photoresist adds to the thickness. However, during etching, the metal is being removed.

That means the panel is becoming less rigid and prone to wrapping around a roller. (Most transportation issues only apply to thin material processing)

Buying an etcher that has great etch uniformity and transportation is key to building a successful etching shop.

Approximate Cost = $97,000


7. Stripper (Chemcut Product)

Resist stripper

Stripping the photoresist from the metal is the next step. As a whole stripping is less technical than the other wet processes. Basically, the resist needs to be in the chemistry long enough to strip.

There are a couple of important factors to consider if you want an efficient stripping line.

First, you need to work with your chemistry supplier and photoresist film supplier to make sure your resist and chemistry are compatible with each other. If they are not compatible you will see your resist stripping off in sheets, as goo, as large pieces, or very fine pieces.

None of these are good!

You want your resist to strip in small chips. The reason you want small chips is that strippers are designed to filter out small chips. If you are getting any other size or goo, this means your resist and chemistry are a mismatch, and the stripper will have a hard time filtering out particles.

This will result in plugged nozzles.

Secondly, you will want to decide what design is best for your shop. Are you running high volume or just a couple of boards a day? This will help you determine how the filtering is set up.

You will also want to understand how the filtering works. If the machine you select does not filter the resist well, you will experience lots of downtime due to nozzle clogging.

No one wants down time, so make sure your stripper has an adequate filtering system.

Approximate Cost = $103,000


5 – 7.    DES (Develop – Etch – Strip)

Many etching shops put all three of these processes in one line. This allows shops to use less operators because the panel will go through all three processes before it needs to be unloaded.

There are some negatives to putting all three together. The line is much larger, so you need a large room.

The processes do not run at the same speed so some chambers may need to be larger than a stand-alone machine. If you move forward with opening a shop a Chemcut employee can help you through this decision process.

Approximate Cost = $360,000  


8. Inspection for Quality Control (Non-Chemcut Product)

The tools needed for inspection after etching will be microscopes, calipers, pin gauges, micrometers, or automated inspection tool. Just like before etching there are many options here and it will depend on your budget.

If you are etching screens, fine lines and spaces, or just a lot of small features the automated inspection tool is great!

However, automated inspection equipment is expensive. So, microscopes, pin gauges, calipers, and micrometers tend to be the go to quality inspection tools used in etching shops.

Approximate Cost = $75,000


9. Wastewater Treatment (Chemcut Product)

There are multiple options for wastewater treatment, but the most popular is a batch wastewater treatment. A batch wastewater treatment system will consist of a collection tank, a treatment tank, filter press, clear well tank, ion exchange, and final tank.

The collection tank will collect all the runoff from your wet processing equipment. All your machines will have some liquid leaving the system. Mostly from your rinses.

The wastewater that is collected can be transferred to the treatment tank (precipitation tank). The wastewater will be treated here, and all the metals will precipitate to the bottom of the tank.

The clear water can be decanted into the clear well tank and if all the metals are removed the water can be transferred to the final tank. From the final tank, the water can be pH corrected and sent down the drain.

The metals (sludge) that settles at the bottom of the treatment tank will be pumped through the filter press. The filter press will remove all the sludge and this sludge can then be shipped off your facility as toxic waste.

The last piece of equipment you will need is a scrubber for the fumes that are being pulled out of your wet processing line.

Approximate Cost = $350,000


10. Facility (Non-Chemcut Product)

If you do not have a facility yet, we recommend talking to an equipment manufacturer so you can plan your facility around the needed equipment. If you already have a facility, no problem.

Most machines can be designed to fit into the space available. However, like mentioned above, purchasing a DES line may be more difficult if your facility is not large enough.

If your facility is too small for a DES line the machines can be broken up into three separate machines or into two. You can have a develop – etch or etch – strip line made to save on operator cost.  

Approximate Cost = 15 – 20% of total equipment investment


11. Environmental Clearances (Non-Chemcut Product)

The cost of environmental clearances will depend on your local and state regulations.

What you will want to do is find out how much chemistry you can have on site.

What are the limits on heavy metals for discharging?

Are any of the chemicals you want to use heavily regulated?

What size scrubber does your local government require you to have?

Getting answers to these questions will help you determine what all you need and if you can feasibly start a chemical etching plant in your current location.

Approximate Cost = ??? This depends on where you are located. Check with your local authorities.


Conclusion

Starting a chemical etching plant is not as easy as “just get an etcher and start making parts.” Building a chemical etching plant requires thorough planning, a large up-front investment, and time to study the process so you experience as little downtime as possible.

We did not put this article together to discourage you from building your plant, we put this together, so you know what it requires to start a successful chemical etching plant. We are here to help you succeed!

Approximate Overall Cost = $1,395,000