As an expert in the field of electronics manufacturing, I've been involved in the design and production of various types of circuit boards, which are the backbone of modern electronic devices. When it comes to the thickness of a circuit board, it's a question that can be answered in a few different ways, depending on the context and the specific type of circuit board in question.

**Step 1: Understanding Circuit Board Thickness**
The thickness of a circuit board, often referred to as its "board thickness" or "TG" (thickness gauge), is a critical parameter that can affect the performance, durability, and manufacturing cost of the board. It is typically measured in inches, although it can also be converted to millimeters for international standards.

Standard Thickness Options
In the context of standard dielectric builds, which are pre-defined layers of insulating material between the conductive layers in a multi-layer board, there are several common thicknesses. The options you've mentioned, ranging from 0.020" to 0.125", are typical thicknesses for PCBs (Printed Circuit Boards). These are standard options that manufacturers offer, and they can be selected based on the requirements of the electronic device the board will be used in.

Custom Stack-up
In addition to standard thicknesses, it's also possible to specify a custom controlled stack-up. This means that the manufacturer can create a circuit board with a thickness that is not part of the standard options. This is often done for specialized applications where the standard thicknesses do not meet the specific needs of the design.

Inner Layer Copper Foil
The thickness of the inner layer copper foil is another factor that can influence the overall thickness of the circuit board. Copper foil is used to create the conductive pathways on the board. The options you've provided, which are ? (unknown or unspecified), 1 ounce, or 2 ounces, refer to the weight of copper per square foot. This can affect the thickness of the board, especially in multi-layer boards where the copper layers can add up.

Factors Affecting Thickness
The thickness of a circuit board can be affected by several factors, including:


1. Dielectric Material: The type and number of layers of dielectric material used between the conductive layers.

2. Copper Foil Thickness: As mentioned, the weight of the copper foil can add to the overall thickness.

3. Plating: Additional plating on the copper can also increase the thickness.

4. Solder Mask: The application of a solder mask, which is a protective layer applied to the board, can add to the thickness.

5. Silk Screen: This is a layer that often includes text and symbols for assembly and reference, which can also contribute to the board's thickness.

Manufacturing Considerations
When manufacturing a circuit board, the thickness is carefully controlled to ensure that the board meets the design specifications and can be reliably used in the intended application. Too thin, and the board may be too flexible or prone to damage; too thick, and it can be more difficult to manufacture and may not fit into the intended device.

Applications and Standards
Different applications may require different thicknesses. For example, a thick board might be used for a high-reliability application where durability is critical, while a thinner board might be used for a consumer electronics product where space and weight are at a premium.

Conclusion
In conclusion, the thickness of a circuit board is a multifaceted consideration that involves standard options, custom specifications, and a variety of manufacturing factors. It's a balance between meeting the technical requirements of the application and the practical considerations of manufacturing and assembly.

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You can use one of our "standard" dielectric builds or specify your own controlled stack-up. We process four layer PCB boards with final thickness of 0.020", 0.031", 0.040", 0.047", 0.062", 0.093" and 0.125". You may select ?, 1 or 2 ounce inner layer copper foil for your board.read more >>