Etching is involved in most of the technology and products we use every day. It is used to make small, complex metal components. It directly shapes a lot of industries, and these industries depend on etching for their accuracy. Etching is a process that transforms thin metal sheets into intricate patterns. There are two approaches towards etching: physical and chemical etching processes. Both work differently.
Continue reading to know about both these methods. We’ll compare different factors between chemical vs physical etching, such as mechanism, accuracy, speed, etc.
What is Chemical Etching?
Chemical etching employs acid solutions for metal removal in targeted locations. The technique is based on photoresist masks, which shield certain parts and expose the rest to acid attack. Material only dissolves where the acid comes into contact with exposed metal. Selective removal makes accurate patterns and structures from flat metal sheets.
Chemical Etching Process Step By Step
- Design transfer: Digital patterns are imprinted onto photomasks with precise dimensions required for final parts
- Metal preparation: The sheets are then properly cleaned. This is to ensure that the photoresist sticks well on the surface
- Resist coating: The metal surface is then covered with photosensitive material using controlled lamination
- Exposure pattern: UV light subsequently illuminates via the photomask, hardening resist only where protection is required
- Development of resist: Developer solution dissolves unhardened photoresist, exposing metal for removal in marked areas
- Treatment with acid: Metal subsequently passes into precision etchant systems, where exposed regions dissolve at controlled rates
- Cleaning final: Lastly, excess photoresist peels off, and finished components are ready for delivery
Materials Used
Most common metals are compatible with this process. Stainless steel of thickness 0.025mm to 1.5mm is generally compatible. Copper reacts rapidly to etchant systems and is thus ideal for use in electronics.
Each material is paired with special acid formulations that have been formulated through generations of testing.
Applications
Photochemical etching is used in the process to make circuit boards, connectors, and other electronic components. To make surgical tools with sharp edges and furnished surfaces, this process is utilized. Automotive producers depend on fuel system filters and sensor housings fabricated by this process. When aerospace requires heat exchangers and light component weight in applications, precision etching provides the weight savings desired.
At TMNetch, we provide high-precision components in all these industries. Our technology and skilled staff guarantee every project is completed to exact specifications. Get in touch with us to talk about your particular needs and how chemical etching can help your next project.
What is Physical Etching?
Physical etching strips away metal by using mechanical forces instead of chemical reactions. High-energy particles or plasma directly hit the metal surface. This atom bombardment knocks off atoms from the material at the molecular level. The method forms exact patterns by controlled physical impact instead of dissolution.
Physical Etching Process Step By Step
- Vacuum chamber setup: Materials feed into sealed chambers where air is pumped out to create suitable conditions
- Mask application: Physical masks or photoresist patterns shield regions that must remain unscathed
- Plasma generation: High-frequency energy then produces ionized gas particles in the chamber
- Ion acceleration: Electric fields propel these charged particles onto the metal surface at high speeds
- Material removal: Energetic ions bombard exposed regions, physically ejecting atoms from the surface
- Process monitoring: Real-time sensors monitor removal rates and provide uniform results across the surface
- Chamber cleaning: Lastly, material that has been removed exits the system, leaving clean finished parts
Materials Used
This process accommodates various materials compared to chemical techniques. Silicon wafers are particularly suitable for semiconductor devices. Titanium and other hard metals are more readily handled by physical removal rather than acid dissolution. Glass substrates are aided by the controllable aspect of ion bombardment. Materials with complicated compositions or those that are chemically sensitive prefer this method.
Applications
To make circuit patterns on silicon wafers for semiconductor fabrication uses physical etching technology. Physical techniques create accurate surface textures and coatings in optical components. MEMS devices demand the precision that physical removal achieves for very small mechanical structures. Exotic materials that are difficult to chemically process are worked with by research labs using this method.
Comparing: Chemical Vs Physical Etching
Mechanism
Both processes work on different mechanisms. Here’s how chemical vs physical etching compares in terms of mechanism:
Chemical Etching:
Employ acids to chemically react with the dissolution of metal. The etching process occurs by the disintegration of the metal bonds at targeted regions. Acid strength and temperature regulate the rate of material removal.
Physical Etching:
Physically displaces metal by direct physical contact. High-energy particles bombard the surface and dislodge atoms. This occurs in vacuum chambers with particle acceleration control.
Precision
Chemical vs physical etching both have different precision:
Chemical Etching:
Provides precision to ±0.025mm in most uses. The method produces smooth edges but may result in minor undercutting. Surface finish remains outstanding upon completion.
Physical Etching:
Provides even tighter tolerances to ±0.005mm when necessary. Directional character provides straight vertical walls. This completely eliminates undercutting issues.
Cost
Here is the cost comparison of both chemical vs physical etching:
Chemical Etching:
Lower upfront cost of setting up equipment. Operating expenses involve purchasing acid and paying disposal costs. High-volume production runs keep individual part prices highly competitive.
Physical Etching:
Expensive vacuum systems and specialized gear are required. Operating expenses vary with the volumes. Total costs rise due to maintenance needs.
Speed
Chemical vs physical etching processes work at different paces. Here’s a comparison between the two:
Chemical Etching:
Processes lots of parts simultaneously effectively. Hundreds of small parts can be accommodated by a single sheet. Total processing takes one to several hours.
Physical Etching:
Processes individual components at a time in the majority of circumstances. This caps the number of parts finished per hour. Intricate patterns take a few hours or days.
Usage
Here’s the difference in usage of chemical vs physical etching:
Chemical Etching:
Best for high-volume manufacturing in various industries. The most prevalent metals and alloys are receptive to this method.
Physical Etching:
It is geared to semiconductor fabrication and research work. This technique is appropriate for the use of materials that chemicals cannot effectively treat.
Which Etching Method Should You Choose?
The choice between chemical vs physical etching depends on your required specifications. Both processes have different advantages. Here are some factors to consider when choosing between chemical vs physical etching:
- Tolerance
- Material type
- Volume of production required
For thin materials under 3mm, chemical etching works best, resulting in complex geometries. But if you are working with thicker materials and simpler shapes, then physical etching may be the option for you.
TMNetch: Leading Chemical Etching Services Provider
With over a decade of experience in photochemical etching, TMNetch serves across various industries. Their precise photochemical etching process produces bur-free, clean complex structures. Here is what sets them apart:
- Exceptional Precision: Obtain close tolerances from ±10 to ±25 microns
- Flexible Material Options: Etch metals from 0.01mm to 3.0mm thick
- Rapid Prototyping: Receive your prototype in as fast as 6 hours
- Free Samples: Test our process with no upfront cost
Industries They Serve
- Aerospace
- Automotive
- Medical
- Electronics
- Circuitry
- Decorative
- Optical
- Industrial Automation
TMNetch is a specialist in the field of chemical etching. Their team of 100+ engineers will work directly with your design requirements. Contact TMNetch to get your prototype in just 6 hours and production in as little as 3 days.
FAQs About Chemical Vs Physical Etching
Is chemical etching cheaper than physical etching?
Yes, chemical etching is cheaper than physical etching because it does not require expensive tools or dies. Not only is chemical etching cheaper, but it also offers unmatched precision for complex components.
Which process is better for mass production?
For mass production of precise and intricate metal components, chemical etching is preferred. In chemical etching, the design changes are very easy to make and provide bur-free final product.
Can chemical etching achieve nanometer precision?
Yes, chemical etching can achieve nanometer precision. Semiconductor devices such as transistor gates, interconnects have precision in nanometers.
What industries benefit the most from physical etching?
Physical etching is best suited for various industries in which precise metal removal is required. It includes the semiconductor industry, medical device manufacturing, aerospace and defense, electronics, etc.
Conclusion
Both chemical vs etching address various manufacturing requirements quite effectively. Chemical processes dominate high-volume production with cost-effectiveness and material flexibility. Your project needs to decide what process is best. At TMNetch, we run up-to-date chemical etching labs with ISO 9001 certification and 15+ years of experience. Our systems manage tolerances as low as ±0.013mm on stainless steel, copper, and aluminum materials used in the automotive, medical, and electronics industries.
