One of the final decisions you may make when it comes to your printed circuit boards is whether to go with a shiny solder mask, also called a glossy finish, or to opt for a matte finish. PCBs function equally well with a glossy finish or a matte finish, so this decision is not critical. In many cases, those ordering PCBs will leave this decision up to the fabricator, who will typically choose a gloss finish by default.
Jump To: What Is a Glossy Finish in PCBs? | What Is a Matte Finish in PCBs? | Benefits of a Gloss Finish on a Circuit Board | Advantages of a Matte Finish on a PCB | Why Choose a Glossy Finish Over a Matte Finish? | Reasons to Choose a Matte Finish Over a Glossy Finish | Learn More About PCB Specifications
For information purposes, and to help you decide whether or not you have a preference, here are the differences between a glossy finish and a matte finish for your PCBs.
What Is a Glossy Finish in PCBs?
A glossy finish for a PCB is a light-reflective solder mask lighter in color than a matte PCB finish. It has a poreless appearance as opposed to the softer look of a matte finish.
What Is a Matte Finish in PCBs?
Matte finishes for PCB solder masks have no shine and tend to appear darker than glossy finishes. They have a soft, porous appearance that does not reflect light.
Benefits of a Gloss Finish on a Circuit Board
Many of the benefits of a solder mask finish depend on the customer’s aesthetic preferences. You might choose a glossy finish over a matte solder mask due to:
- Aesthetic value: Because of glossy finishes’ role as the default choice for solder masks, many customers consider them the classic PCB appearance. Their shine gives them what many perceive as a more modern look.
- Appearance of wear: The reflective properties of a glossy finish tend to make signs of wear look less prominent.
- Scratch resistance: Because of its harder surface, a glossy finish has higher scratch resistance than a matte finish.
Advantages of a Matte Finish on a PCB
Your preferences in PCB appearance will also determine whether you’ll want a matte finish instead of a glossy solder mask. A matte finish may make some aspects of fabrication easier. However, an experienced PCB company will provide quality results regardless of solder mask finish. The potential advantages of a matte finish include:
- Visibility during inspection: A matte finish does not have shine under any lighting used during inspection. As a result, you can more easily see the PCB’s details.
- Problem detection: Matte finishes make problems more evident than glossy finishes. During inspection, it becomes easier to detect issues on a matte finish due to increased visibility.
- Solder ball reduction: Research suggests that matte finishes reduce a PCB’s risk of solder ball formation. Data indicates that a lower gloss level on PCBs results in lower solder ball levels.
Why Choose a Glossy Finish Over a Matte Finish?
The main difference between a gloss finish and a matte finish is an aesthetic one, and many people feel that a gloss finish simply looks better. Gloss solder masks are shiny. They reflect light and look lighter, while matte finishes are dull and dark. Gloss solder mask has a hard shell finish while a matte finish is softer looking.
Matte finishes may also scratch more easily and show residue or surface cosmetics better, although scratches on a gloss finish will show more. If you expect the look of your PCB will have a positive effect on your assemblers or anyone who may end up looking at them, you may want to go with the gloss finish. Just keep in mind that the high light reflectivity can be a nuisance to vision during assembly in some cases.
As a PCB customer, you may want to choose a glossy finish over a matte finish when:
- Appearance matters for your PCB: In applications where appearance impacts your PCB marketing, a glossy finish can help by increasing aesthetic appeal.
- You have no specific preference: If you don’t have a particular finish preference, remember that glossy finishes serve as the industry default for most suppliers.
Reasons to Choose a Matte Finish Over a Glossy Finish
Although it is no more cost-effective or efficient to choose a matte finish over a glossy one, there is one consideration that may cause some to prefer the matte finish, and it involves solder balls. If you are concerned that solder balls may be a problem for you, you may be inclined to choose a matte finish. This is because, while there are several factors that contribute to solder balls, one is the level of surface roughness. The smoother the surface, the more likely it is that solder will ball up.
The theory behind this is that molten solder behaves differently on rough surfaces and smooth surfaces. On rough surfaces, it tends to form a convex shape, reducing the area solder balls can attach to, while on smoother surfaces it tends to take a concave shape. Since matte finishes are softer and more porous, as opposed to the smooth, hard shell of the glossy finish, many experts feel that a matte finish will result in fewer solder balls. With all of this said, glossy finishes are used all the time on PCBs, so you may not find this to be a particular problem.
When you’re considering your choice of solder mask finish, you might prefer a matte option in these situations:
- You want to streamline production as much as possible: When you consider production accuracy a top priority, a matte finish may give you more peace of mind during fabrication. However, skilled PCB companies should detect errors in either finish type.
- Participation in quality assurance matters to you: If you plan to inspect your PCB yourself after production, a matte finish can help with the process. It shows errors more clearly for you to provide accurate feedback to your PCB company.
Learn More About PCB Specifications
For more information on PCBs, or to order PCBs for your company, contact Millennium Circuits Limited — the printed circuit board and printed circuit board accessories experts — today.