In-depth Analysis Of Wet Etching vs. Dry Etching for Business

Feature image for wet etching vs dry etching 

Wet and dry etching are potential methods of manufacturing parts for aerospace, electronics, MEMS (Micro-Electro-Mechanical Systems), and semiconductor industries, among many others. 

Like EDM, wet and dry etching are subtractive methods. However, since they have distinct pros and cons, it is important to choose which one to use for parts. 

Wet etching uses etchantsor liquid chemicals to remove materials. It involves several chemical reactions that culminate in the formation of the desired shape on a part. Dry etching etchant gasses are used to remove material. A chemical beam or particle beams, or a blend of the two can be used. 

Choosing between Wet etching vs dry etching is not straightforward because of the intricacies and good characteristics that each provides. That’s why ProleanTech is here. We are the home of advanced machining expertise for the best results. 

Our engineers are experienced in these and many other processes. Add that to our state-of-the-art machinery, and you have the best setup for your wet-etched and dry-etched parts for different industries. 

An Overview Of Etching  

Etching is a material removal technique based on physical or chemical interactions as captured in dry etching vs wet etching. Through lithography, some parts of a material can be exempted from material removal. This creates patterns after the material removal process is complete. 

An etched sheet metal 

ProleanTech has vast experience in etching involving many materials. We can etch both standard thickness materials and thin films, depending on the project requirements. 

The etching definition correctly implies the etching treatment has many benefits – Versatility, cost-effectiveness, lost cost tooling, quick turnaround, repeatability, and so on. Given the involvement of chemicals, there are many other considerations for the process, safety being a key one. 

You can get similar considerations in the Complete Guide to EDM Machining, which highlights safety factors such as using safety equipment, understanding how the machine works, and overall safe handling of the equipment. 

There are different etching methods to consider depending on user part requirements. Two main categories emerge: dry etching vs wet etching. 

We will look at the processes in detail in the next section. 

The main observation is that these processes are non-physical, so they don’t put the substrate under mechanical stress. As indicated in the EDM process overview, EDM is a non-conventional machining process, and we can liken it to etching in that respect. 

What is Wet Etching And Its Variations For Your Parts? 

Wet etching uses a chemical liquid (acidic or basic) to remove unwanted material from a substrate. Another name for the chemical is etchant. Wet etching is a simple process that involves simple equipment and is characterized by material erosion. 

The substrate is immersed in the chemical liquid, so the assumption is that the erosion would occur equally in all directions. This kind of erosion is called isotropic etching. 

On the contrary, there is anisotropic etching, which does not produce erosion underneath. It does this by controlling the etchant-substrate reaction.

Wet etching 

More On The Types of Wet Etching To Optimize Parts Quality

There are two main types of wet etching, namely, isotropic etching and anisotropic etching. We have touched on these processes briefly above. 

Isotropic Etching

Isotropic etching

The term isotropic comes from the Greek words “iso” and “tropos”, which mean “equal” and “a turn”, respectively. Isotropic etching is, therefore, characterized by material removal in all directions. 

Anisotropic Etching

Anisotropic etching

Anistropic etching is different from isotropic etching because it applies etching in unique intensities based on the direction. 

Business Advantages Of Wet Etching: Cost-effectiveness, Simplicity, And Speed 

Here are the main advantages of wet etching:

The Etching Machine Is Easy To Set Up

The wet etching method is simple compared to dry etching. Its controllable variables are fewer; hence, setting it up is easy and takes a short time. 

Wet etching setup

It is a Cost-Effective Etching Method

Since setting up the machinery is simple and the whole etching treatment uncomplicated, this translates to a lower cost of the process. 

Wet Etching Is Fast 

This method is faster compared to dry etching. It is a great choice if the parts are uncomplicated and needed in large volumes. 

What Is Dry Etching And Its Versions For Your Parts?

Dry etching uses high vacuum plasma instead of the liquid chemical used in wet etching. The gas is converted into plasma in a gas environment before being used to remove material from the substrate. 

Typically, the different types of dry etching involve relatively expensive equipment, but have high precision. 

The Types of Dry Etching And Their Innovative Relevance

Dry etching can be categorized as ICP-RIE Etching, Ion Beam Etching (IBE), and Reactive Ion Etching (RIE). 

ICP-RIE Etching

ICP-RIE Etching is an advanced version of dry etching entailing Inductively Coupled Plasma (ICP) and Reactive Ion Etching (RIE) components. 

The plasma production in ICP is based on an electromagnetic coil. For RIE, the fundamental process is characterized by the control of ions using an electric field. 

Ion Beam Etching (IBE)

In IBE, argon ions form a beam, which is directed on the surface to remove material. These ions can carry energy of about 3 kilo electronvolts (keV). 

Ion Beam Etching

Reactive Ion Etching (RIE)

Then, there is RIE, which uses chemically reactive ions to remove material. 

Reactive Ion Etching 

Advantages Of Dry Etching For Accurate And Innovative Parts 

Like wet etching, dry etching has its advantages. We have outlined the most prominent ones here. 

Higher Control And Precision

Dry etching is better for control and precision. Anisotropic etching with these capabilities makes the process perfect for precision processes such as microelectronics and etching in semiconductor manufacture. 

Dry etching of a semiconductor wafer

It Is A Versatile Method 

Plasma etching is very versatile, particularly concerning the types of materials. Even chemical-sensitive materials are applicable for this method. Therefore, it widens the types of projects one can handle. 

It Is A Cleaner Etching Process 

The dry etching process does not require chemicals. This removes the contamination risk. 

What Is The Difference Between Wet And Dry Etching?

Like the case of Wire EDM vs Sinker EDM: Key Differences, wet and dry etching have their differences, a fact that prompts the manufacturer and the client to consider several angles before deciding which one to use. 

ProleanTech considers all the critical elements and capabilities of the processes before choosing and advising clients on the best method. We use our years of experience handling modern, intricate machining processes. 

The elements for decision-making in Wet etching vs dry etching include the technology, selectivity, environmental effect, and risk of surface damage. Let us compare these technologies through the table below. 

Here’s a look at some of these elements in detail:

Process Control And Precision 

Dry etching is better for the generation of detailed patterns because it has higher control and precision capability. It is the preferred technique for vertical walls and tight aspect ratios. Since this method is anistropic, controlling it to remove material in only one direction is possible. 

Precisely dry etched part

By its nature, wet etching is less precise and controllable. Removal of material uniformly in all directions means achieving precision of dry etching is challenging. Since control is not top-notch, this method is preferable for precise patterns. 

Etching Process Cost 

Dry etching is a relatively complicated process that requires expensive equipment compared to the cost of wet etch equipment. Typical components of the dry etching equipment are power supply, control system, and vacuum chamber. 

Things are less complicated for the wet etching technique. Typically, the key component of the setup is the etching tank. The cost of operating and maintaining this system is less compared to the dry etching setup. 

The Speed And Effectiveness Of The Etching Process 

The wet etching process is typically faster than dry etching, reminding of a relatable difference in EDM vs Milling. The wet chemicals work on the material fast. This method would be ideal for high volume production of patterns or large parts. 

Dry etching is slower because precision and control are critical. The process is more complicated, so it takes more time to produce a pattern. Dry etching is less efficient for high-volume, less detailed production. 

When To Choose Wet Etching Or Dry Etching

The specifics of a project will determine the most preferred method between wet etching vs dry etching. At ProleanTech, we have a few recommendations depending on the following points.

Use Wet Etched Parts

• When the budget is the biggest factor, and you need the lower-cost option
• If you need less complicated but larger shapes or features
• For silicon wet etching and other materials that work well with chemical etchants 
• For larger parts, that doesn’t have to be too precise

Use Dry Etching Method

• If the required patterns are precise and the process must be closely-controlled
• For vertical etching where undercutting is undesirable 
• If the material being etched is chemical-sensitive 
• If the etching treatment requires surface cleaning

Whichever technology you choose, you can be sure to achieve superior results at ProleanTech. Our EDM Machining Services are a perfect pointer of the levels you can attain for parts with us. We are capable of delivering tolerances of 0.0001” (2 µm) and surface finishes of as low as 4 µm. 

Ask for a quote now to get the best etching services today for PCBs, aerospace sensors, watches, and fuel injectors, and more. 

AnA etching-produced PCB

Alt text: A close-up image of a printed circuit board (PCB) with intricate metal traces and mounted parts

Conclusion 

Wet etching vs dry etching is a good debate because the two processes are central to parts manufacturing for solar energy, aerospace, semiconductor, and many other industries. 

Wet etching is relatively affordable and fast while dry etching costs more but is more controllable and precise. Your project’s requirements will dictate the ideal technique. 

ProleanTech is here to analyze all the project requirements and choose the best method for you. We are ready to manufacture your components using the most advanced techniques for reliability and cost-effectiveness. 

If  you are interested in learning more about how we go about etching and ordering our custom services, Contact us today!

FAQs

What is the purpose of wet etching?

The purpose of wet etching is to use chemical solutions to selectively remove material from a part (substrate) as needed in the manufacture of microelectronics, semiconductors, and such items.  

Is dry etching more expensive than wet etching?

Yes, dry etching is typically more expensive than wet etching due to the complexity of the process, the cost of the equipment, and the higher time required to complete a task. 

What liquid is used for etching?

There are many liquids for etching based on the substrate, including Nitric acid (HNO₃), Potassium hydroxide (KOH), and Hydrofluoric acid (HF). 

Which of the following are advantages of the wet etching process?

The advantages of the wet etching process are uniform etching for large areas, cost-effectiveness, and high process speed, among others. 

What is the difference between wet etch and Rie?

The difference is that wet etching uses liquid chemicals to etch or remove material from a substrate, while RIE uses a vacuum chamber and plasma to remove material. 

Is etching still popular?

Yes, etching is still a popular manufacturing method in different industries such as semiconductors and microelectronics. 

How can you tell if an etching is original?

You can ascertain the originality of an etching through plate marks, paper quality, and ink texture. You can check for dimensional accuracy, material properties, and quality control documentation for industrial etching.