### PCB Negative Film Output Process
**What is the difference between PCB positive film and negative film?**
The distinction between PCB positive film and negative film lies in their opposite effects during the manufacturing process.
The function of PCB positive film: In this method, areas where lines are drawn result in the retention of copper on the printed board, while areas without lines see the removal of copper. This is typically applied to signal layers such as the top and bottom layers.
The function of PCB negative film: In contrast, in this approach, areas where lines are drawn lead to the removal of the copper coating from the printed board, while areas without lines retain the copper coating. This method is primarily used for internal planes (internal power/ground planes), which facilitate the layout of power and ground lines. On these layers, traces or other elements are considered copper-free zones, meaning that the working layer is negative.
**PCB negative film output process: What is the difference between PCB positive film and negative film output processes?**
**Negative Film:** Generally, when we discuss the tenting process, the chemical solution employed is acid etching.
Negative film is characterized by a transparent circuit or copper surface after the film is produced, while the unneeded areas appear black or brown. During the exposure of the circuit process, the transparent sections are chemically influenced by the light of the dry film resist, causing hardening. In the subsequent developing process, the unhardened dry film is washed away, resulting in the etching of only the copper foil areas (the black or brown sections of the negative film) that have been removed by the dry film. This leaves the dry film intact, preserving the circuit we need (the transparent parts of the negative film). Once the film is removed, the desired circuit remains. In this process, the film must cover the holes, requiring slightly higher exposure standards and film specifications. However, its manufacturing process is rapid.
**Positive Film:** Typically, when discussing the pattern process, the chemical solution used is alkaline etching.
If the positive film is viewed as an inverse of the negative, the required circuit or copper surface appears black or brown, while the rest remains transparent. After exposing the circuit process, the transparent areas are again affected by the light of the dry film resist, leading to hardening. The subsequent development process washes away the unhardened dry film. Following this, a tin-lead plating process occurs, where tin-lead is applied to the copper surface that has been stripped of dry film in the previous step (development). The film is then removed (the dry film hardened by light), and during the etching process, an alkaline solution is used to etch away the copper foil (the transparent areas of the negative) that is not protected by tin and lead. This leaves us with the desired circuit (the black or brown sections of the negative).
**Differences Between PCB Positive Film and Negative Film** — What are the advantages of PCB positive film, and where is it primarily used?
Negative film helps reduce file size and computational load, displaying areas without copper while hiding those with copper. This significantly decreases data volume and the burden on computer displays in the ground power layer. However, with modern computer configurations, this issue is less critical. I would recommend caution with negative film, as it is prone to errors; if pads are not properly designed, it could lead to short circuits or other issues.
There are various methods for managing power supply distribution conveniently. Positive film can also be easily partitioned through alternative techniques, making the use of negative film unnecessary.
**What is the difference between PCB positive film and negative film?**
The distinction between PCB positive film and negative film lies in their opposite effects during the manufacturing process.
The function of PCB positive film: In this method, areas where lines are drawn result in the retention of copper on the printed board, while areas without lines see the removal of copper. This is typically applied to signal layers such as the top and bottom layers.
The function of PCB negative film: In contrast, in this approach, areas where lines are drawn lead to the removal of the copper coating from the printed board, while areas without lines retain the copper coating. This method is primarily used for internal planes (internal power/ground planes), which facilitate the layout of power and ground lines. On these layers, traces or other elements are considered copper-free zones, meaning that the working layer is negative.
**PCB negative film output process: What is the difference between PCB positive film and negative film output processes?**
**Negative Film:** Generally, when we discuss the tenting process, the chemical solution employed is acid etching.
Negative film is characterized by a transparent circuit or copper surface after the film is produced, while the unneeded areas appear black or brown. During the exposure of the circuit process, the transparent sections are chemically influenced by the light of the dry film resist, causing hardening. In the subsequent developing process, the unhardened dry film is washed away, resulting in the etching of only the copper foil areas (the black or brown sections of the negative film) that have been removed by the dry film. This leaves the dry film intact, preserving the circuit we need (the transparent parts of the negative film). Once the film is removed, the desired circuit remains. In this process, the film must cover the holes, requiring slightly higher exposure standards and film specifications. However, its manufacturing process is rapid.
**Positive Film:** Typically, when discussing the pattern process, the chemical solution used is alkaline etching.
If the positive film is viewed as an inverse of the negative, the required circuit or copper surface appears black or brown, while the rest remains transparent. After exposing the circuit process, the transparent areas are again affected by the light of the dry film resist, leading to hardening. The subsequent development process washes away the unhardened dry film. Following this, a tin-lead plating process occurs, where tin-lead is applied to the copper surface that has been stripped of dry film in the previous step (development). The film is then removed (the dry film hardened by light), and during the etching process, an alkaline solution is used to etch away the copper foil (the transparent areas of the negative) that is not protected by tin and lead. This leaves us with the desired circuit (the black or brown sections of the negative).
**Differences Between PCB Positive Film and Negative Film** — What are the advantages of PCB positive film, and where is it primarily used?
Negative film helps reduce file size and computational load, displaying areas without copper while hiding those with copper. This significantly decreases data volume and the burden on computer displays in the ground power layer. However, with modern computer configurations, this issue is less critical. I would recommend caution with negative film, as it is prone to errors; if pads are not properly designed, it could lead to short circuits or other issues.
There are various methods for managing power supply distribution conveniently. Positive film can also be easily partitioned through alternative techniques, making the use of negative film unnecessary.
