1. **Additive Process Addition**
This refers to the direct growth of local conductor lines with a chemical copper layer on the surface of a non-conductive substrate, facilitated by an additional resistance agent (for details, see p.62, No. 47, Journal of Circuit Board Information). The methods used in circuit boards can be categorized into full addition, semi-addition, and partial addition.
2. **Backing Plates**
Backing plates are a type of circuit board with substantial thickness (such as 0.093″ or 0.125″) specifically designed for plugging and making contact with other boards. The process involves inserting a multi-pin connector into the press-fit through holes without soldering, followed by wiring each guide pin of the connector. A standard circuit board can be inserted into the connector. Since soldering is not possible on this specialized board, the quality and aperture requirements for the hole wall and guide pin are particularly stringent, and the order quantities are usually low. Consequently, general circuit board manufacturers often hesitate to accept such orders, making this a niche, high-end industry in the United States.
3. **Build-Up Process**
This method represents a novel approach to thin multilayer plates, with its roots tracing back to IBM’s SLC process, which began trial production at the Yasu factory in Japan in 1989. Based on traditional double-sided plates, the two outer layers are fully coated with liquid photosensitive precursors like probmer 52. After semi-hardening and resolving the photosensitive image, a shallow “photo via” connected to the next lower layer is created. Comprehensive conductor layers are then achieved through chemical copper and electroplated copper. Following line imaging and etching, new wires and buried or blind holes interconnected with the lower layer are formed. This method allows for the desired number of layers in a multilayer board through repeated layering, effectively circumventing the costly mechanical drilling process and reducing hole diameters to below 10 mil. Over the past five to six years, various innovative multilayer board technologies that embrace layer-by-layer construction have gained traction among manufacturers in the U.S., Japan, and Europe, leading to the widespread recognition of these build-up processes, with over ten products currently available on the market. Besides the aforementioned “photosensitive pore forming,” other methods such as alkaline chemical etching, laser ablation, and plasma etching are employed for organic plates post-copper removal. Furthermore, a novel type of “resin-coated copper foil” embedded with semi-hardening resin allows for the production of thinner, denser, and more compact multilayer boards through sequential lamination. In the future, diverse personal electronic products will pave the way for this truly thin, short, and multilayer technology.
4. **Cermet Taojin**
Ceramic powder is combined with metal powder, followed by the addition of an adhesive as a coating. This material can serve as the “resistor” placement on the circuit board’s surface (or inner layer) through thick or thin film printing, effectively replacing external resistors during assembly.
5. **Co-firing**
This process involves manufacturing ceramic hybrid circuit boards. Circuits printed with various precious metal thick film pastes on small boards are subjected to high-temperature firing. The organic carriers in the paste are burned away, leaving behind interconnected lines of precious metal conductors.
6. **Crossover Crossing**
This refers to the vertical intersection of horizontal and vertical conductors on the board’s surface, where the intersection drop is filled with an insulating medium. Typically, a carbon film jumper is added on the green paint surface of a single panel, or wiring is added above and below the layer, creating this “crossing.”
7. **Create Wiring Board**
This term describes the formation of a multi-wiring board by attaching circular enamelled wire to the board surface and adding through holes. This composite board performs better in high-frequency transmission lines compared to flat square circuits formed by conventional PCB etching.
8. **Dycostrate Plasma Etching Hole Increasing Layer Method**
Developed by Diconex, a company based in Zurich, Switzerland, this build-up process etches copper foil at each hole position on the plate surface. The board is then placed in a vacuum environment filled with CF4, N2, and O2, ionizing under high voltage to create a highly active plasma, which etches the substrate at the hole positions to produce small pilot holes (below 10 mil). The commercial process is known as Dycostrate.
9. **Electro Deposited Photoresist**
This innovative construction method for “photoresist” was initially designed for “electric painting” on complex metal objects and has recently been adapted for photoresist applications. It employs electroplating to evenly coat charged colloidal particles of optically sensitive resin onto the circuit board’s copper surface as an anti-etching inhibitor. Currently, it is used in mass production for direct copper etching processes on inner plates. ED photoresist can function as either “anode type” or “cathode type,” depending on the operational method, and is available in negative and positive working types. While negative working ED photoresist has been commercialized for planar use, it faces challenges in through-hole photosensitization, limiting its application for outer plate image transfer. Positive ED photoresist, being a photosensitive decomposition film, shows potential for outer plates and is under commercial development in Japan to facilitate the production of finer lines.
10. **Flush Conductor Embedded Circuit, Flat Conductor**
This unique circuit board features a completely flat surface with all conductor lines embedded within the plate. In single panel construction, part of the copper foil on a semi-cured substrate is etched using an image transfer method to create the circuit. The surface circuit is then pressed into the semi-cured plate under high temperature and pressure, completing the resin hardening process. The result is a circuit board with all flat lines embedded. A thin copper layer is often etched off the surface to allow for plating with a 0.3 mil nickel layer, a 20 micro-inch rhodium layer, or a 10 micro-inch gold layer to minimize contact resistance and facilitate sliding contact. However, PTH is not suitable for this method to avoid damage during pressing, and achieving a completely smooth surface can be challenging, especially at high temperatures. This technology is also referred to as the etch and push method, resulting in a flush bonded board suitable for specialized applications like rotary switches and wiring contacts.
11. **Frit Glass Frit**
In addition to precious metal chemicals, glass powder is incorporated into thick film (PTF) printing paste to enhance agglomeration and adhesion during high-temperature firing. This process allows the printing paste on a blank ceramic substrate to form a solid precious metal circuit system.
12. **Full Additive Process**
This method involves growing selective circuits on a completely insulated plate surface through electrodeposition (mostly chemical copper), known as the “full addition method.” A common misconception is the term “full electroless.”
13. **Hybrid Integrated Circuit**
This circuit utilizes precious metal conductive ink applied to a small porcelain thin base plate through printing, followed by high-temperature firing to burn off organic materials, leaving a conductor circuit. It serves as a circuit carrier between printed circuit boards and semiconductor integrated circuit devices, falling under thick film technology. Initially used in military or high-frequency applications, its growth has slowed due to rising costs, decreased military demand, and challenges in automatic production, alongside the increasing miniaturization and precision of circuit boards.
14. **Interposer Interconnect Conductor**
An interposer refers to any insulating object that supports two layers of conductors, which can be connected by adding conductive fillers at the connection points. For instance, filling the bare holes of multi-layer boards with silver or copper paste to replace conventional copper hole walls, or using materials like vertical unidirectional conductive adhesive layers, fall under this category of interposers.
This refers to the direct growth of local conductor lines with a chemical copper layer on the surface of a non-conductive substrate, facilitated by an additional resistance agent (for details, see p.62, No. 47, Journal of Circuit Board Information). The methods used in circuit boards can be categorized into full addition, semi-addition, and partial addition.
2. **Backing Plates**
Backing plates are a type of circuit board with substantial thickness (such as 0.093″ or 0.125″) specifically designed for plugging and making contact with other boards. The process involves inserting a multi-pin connector into the press-fit through holes without soldering, followed by wiring each guide pin of the connector. A standard circuit board can be inserted into the connector. Since soldering is not possible on this specialized board, the quality and aperture requirements for the hole wall and guide pin are particularly stringent, and the order quantities are usually low. Consequently, general circuit board manufacturers often hesitate to accept such orders, making this a niche, high-end industry in the United States.
3. **Build-Up Process**
This method represents a novel approach to thin multilayer plates, with its roots tracing back to IBM’s SLC process, which began trial production at the Yasu factory in Japan in 1989. Based on traditional double-sided plates, the two outer layers are fully coated with liquid photosensitive precursors like probmer 52. After semi-hardening and resolving the photosensitive image, a shallow “photo via” connected to the next lower layer is created. Comprehensive conductor layers are then achieved through chemical copper and electroplated copper. Following line imaging and etching, new wires and buried or blind holes interconnected with the lower layer are formed. This method allows for the desired number of layers in a multilayer board through repeated layering, effectively circumventing the costly mechanical drilling process and reducing hole diameters to below 10 mil. Over the past five to six years, various innovative multilayer board technologies that embrace layer-by-layer construction have gained traction among manufacturers in the U.S., Japan, and Europe, leading to the widespread recognition of these build-up processes, with over ten products currently available on the market. Besides the aforementioned “photosensitive pore forming,” other methods such as alkaline chemical etching, laser ablation, and plasma etching are employed for organic plates post-copper removal. Furthermore, a novel type of “resin-coated copper foil” embedded with semi-hardening resin allows for the production of thinner, denser, and more compact multilayer boards through sequential lamination. In the future, diverse personal electronic products will pave the way for this truly thin, short, and multilayer technology.
4. **Cermet Taojin**
Ceramic powder is combined with metal powder, followed by the addition of an adhesive as a coating. This material can serve as the “resistor” placement on the circuit board’s surface (or inner layer) through thick or thin film printing, effectively replacing external resistors during assembly.
5. **Co-firing**
This process involves manufacturing ceramic hybrid circuit boards. Circuits printed with various precious metal thick film pastes on small boards are subjected to high-temperature firing. The organic carriers in the paste are burned away, leaving behind interconnected lines of precious metal conductors.
6. **Crossover Crossing**
This refers to the vertical intersection of horizontal and vertical conductors on the board’s surface, where the intersection drop is filled with an insulating medium. Typically, a carbon film jumper is added on the green paint surface of a single panel, or wiring is added above and below the layer, creating this “crossing.”
7. **Create Wiring Board**
This term describes the formation of a multi-wiring board by attaching circular enamelled wire to the board surface and adding through holes. This composite board performs better in high-frequency transmission lines compared to flat square circuits formed by conventional PCB etching.
8. **Dycostrate Plasma Etching Hole Increasing Layer Method**
Developed by Diconex, a company based in Zurich, Switzerland, this build-up process etches copper foil at each hole position on the plate surface. The board is then placed in a vacuum environment filled with CF4, N2, and O2, ionizing under high voltage to create a highly active plasma, which etches the substrate at the hole positions to produce small pilot holes (below 10 mil). The commercial process is known as Dycostrate.
9. **Electro Deposited Photoresist**
This innovative construction method for “photoresist” was initially designed for “electric painting” on complex metal objects and has recently been adapted for photoresist applications. It employs electroplating to evenly coat charged colloidal particles of optically sensitive resin onto the circuit board’s copper surface as an anti-etching inhibitor. Currently, it is used in mass production for direct copper etching processes on inner plates. ED photoresist can function as either “anode type” or “cathode type,” depending on the operational method, and is available in negative and positive working types. While negative working ED photoresist has been commercialized for planar use, it faces challenges in through-hole photosensitization, limiting its application for outer plate image transfer. Positive ED photoresist, being a photosensitive decomposition film, shows potential for outer plates and is under commercial development in Japan to facilitate the production of finer lines.
10. **Flush Conductor Embedded Circuit, Flat Conductor**
This unique circuit board features a completely flat surface with all conductor lines embedded within the plate. In single panel construction, part of the copper foil on a semi-cured substrate is etched using an image transfer method to create the circuit. The surface circuit is then pressed into the semi-cured plate under high temperature and pressure, completing the resin hardening process. The result is a circuit board with all flat lines embedded. A thin copper layer is often etched off the surface to allow for plating with a 0.3 mil nickel layer, a 20 micro-inch rhodium layer, or a 10 micro-inch gold layer to minimize contact resistance and facilitate sliding contact. However, PTH is not suitable for this method to avoid damage during pressing, and achieving a completely smooth surface can be challenging, especially at high temperatures. This technology is also referred to as the etch and push method, resulting in a flush bonded board suitable for specialized applications like rotary switches and wiring contacts.
11. **Frit Glass Frit**
In addition to precious metal chemicals, glass powder is incorporated into thick film (PTF) printing paste to enhance agglomeration and adhesion during high-temperature firing. This process allows the printing paste on a blank ceramic substrate to form a solid precious metal circuit system.
12. **Full Additive Process**
This method involves growing selective circuits on a completely insulated plate surface through electrodeposition (mostly chemical copper), known as the “full addition method.” A common misconception is the term “full electroless.”
13. **Hybrid Integrated Circuit**
This circuit utilizes precious metal conductive ink applied to a small porcelain thin base plate through printing, followed by high-temperature firing to burn off organic materials, leaving a conductor circuit. It serves as a circuit carrier between printed circuit boards and semiconductor integrated circuit devices, falling under thick film technology. Initially used in military or high-frequency applications, its growth has slowed due to rising costs, decreased military demand, and challenges in automatic production, alongside the increasing miniaturization and precision of circuit boards.
14. **Interposer Interconnect Conductor**
An interposer refers to any insulating object that supports two layers of conductors, which can be connected by adding conductive fillers at the connection points. For instance, filling the bare holes of multi-layer boards with silver or copper paste to replace conventional copper hole walls, or using materials like vertical unidirectional conductive adhesive layers, fall under this category of interposers.
