Occam Process
Encyclopedia
The Occam Process is a solder
-free, Restriction of Hazardous Substances Directive
(RoHS) compliant method for use in the manufacturing of electronic circuit boards and was developed by Verdant Electronics. It combines the usual two steps of the construction of printed circuit board
s (PCBs) followed by the population process of placing various leaded and non-leaded electronic components into one process.
. These holes are then plated with a conductive, copper connection (vias
) from the top of this layer to the leads. If needed, other encapsulation layers of components or vias can be placed on top of each other to make multi-level circuit connections. This construction is then coated with copper where needed to provide traces. Thus, this finished circuit board can now receive a conformal coating
to protect against the environment, and then be placed into an assembly housing or be sent to another section for mechanical and/or electrical connections with other PCBs.
(electrically conductive structures formed in this process) and other issues in the manufacturing process which are avoided by the Occam Process.
PCB’s themselves are usually created by use of a phenolic resin, itself a corrosive, toxic substance completely removed from the Occam Process. Also, the nitric acid or ferric chloride used to etch traces into the boards is also removed from the process.
Since the PCB and parts population stages happen in the same process in the same plant, a company would no longer need to wait for delivery of ordered PCB’s to begin manufacturing.
The high temperatures usually seen by PCB’s inside of a reflow soldering
oven are avoided by use of this process. This means that any issue of moisture sensitivity
(MSL) in components by outgassing of moisture is completely avoided. This also then removes the storage equipment and processes needed to keep the moisture levels low in more intricate and expensive chips.
” requiring a complete change in current manufacturing processes. Therefore cost concerns for manufacturers needing new equipment, labour concerns for current PCB manufactures and others will need to be solved or addressed before widespread adoption of this process.
Although many toxic chemicals are removed from the traditional process, Occam’s increased use of encapsulation by epoxy could mean more of that sort of waste. The usual additives in epoxy have been shown to mimic estrogen possibly resulting in adverse hormonal responses in humans.
(1288 - 1348) who said: “It is vanity to do with more that which can be done with less.”
Solder
Solder is a fusible metal alloy used to join together metal workpieces and having a melting point below that of the workpiece.Soft solder is what is most often thought of when solder or soldering are mentioned and it typically has a melting range of . It is commonly used in electronics and...
-free, Restriction of Hazardous Substances Directive
Restriction of Hazardous Substances Directive
The Directive on the restriction of the use of certain hazardous substances in electrical and electronic equipment 2002/95/EC was adopted in February 2003 by the European Union. The RoHS directive took effect on 1 July 2006, and is required to be enforced and become law in each member state...
(RoHS) compliant method for use in the manufacturing of electronic circuit boards and was developed by Verdant Electronics. It combines the usual two steps of the construction of printed circuit board
Printed circuit board
A printed circuit board, or PCB, is used to mechanically support and electrically connect electronic components using conductive pathways, tracks or signal traces etched from copper sheets laminated onto a non-conductive substrate. It is also referred to as printed wiring board or etched wiring...
s (PCBs) followed by the population process of placing various leaded and non-leaded electronic components into one process.
The Occam process
Electronic components are first positioned onto an adhesive layer of a temporary or permanent substrate according to the customers needs and design parameters. Then, the pre-tested, burned-in components are held firm in their positions through encapsulating them in insulating material and the entire assembly is then inverted. The adhesive layer is then cut (after removing the temporary substrate if it exists) or drilled out over the component leads mechanically or by laser ablationLaser ablation
Laser ablation is the process of removing material from a solid surface by irradiating it with a laser beam. At low laser flux, the material is heated by the absorbed laser energy and evaporates or sublimates. At high laser flux, the material is typically converted to a plasma...
. These holes are then plated with a conductive, copper connection (vias
Via (electronics)
A via is a vertical electrical connection between different layers of conductors in a physical electronic circuit.- In IC :In integrated circuit design, a via is a small opening in an insulating oxide layer that allows a conductive connection between different layers. A via on an integrated circuit...
) from the top of this layer to the leads. If needed, other encapsulation layers of components or vias can be placed on top of each other to make multi-level circuit connections. This construction is then coated with copper where needed to provide traces. Thus, this finished circuit board can now receive a conformal coating
Conformal coating
Conformal coating material is applied to electronic circuitry to act as protection against moisture, dust, chemicals, and temperature extremes that, if uncoated , could result in damage or failure of the electronics to function...
to protect against the environment, and then be placed into an assembly housing or be sent to another section for mechanical and/or electrical connections with other PCBs.
Main advantages
The 2006, European, RoHS regulations prompted the research needed to move from traditional lead based solder connection processes to a more environmentally friendly approach. Much manufacturing is currently being done with tin-based solder to address this issue. Using tin requires much higher reflow temperatures and can result in rework stages due to electric shorts caused by tin-whiskersWhisker (metallurgy)
Metal whiskering is a crystalline metallurgical phenomenon involving the spontaneous growth of tiny, filiform hairs from a metallic surface. The effect is primarily seen on elemental metals but also occurs with alloys....
(electrically conductive structures formed in this process) and other issues in the manufacturing process which are avoided by the Occam Process.
PCB’s themselves are usually created by use of a phenolic resin, itself a corrosive, toxic substance completely removed from the Occam Process. Also, the nitric acid or ferric chloride used to etch traces into the boards is also removed from the process.
Since the PCB and parts population stages happen in the same process in the same plant, a company would no longer need to wait for delivery of ordered PCB’s to begin manufacturing.
The high temperatures usually seen by PCB’s inside of a reflow soldering
Reflow soldering
Reflow soldering is a process in which a solder paste is used to temporarily attach one or several electrical components to their contact pads, after which the entire assembly is subjected to controlled heat, which melts the solder, permanently connecting the joint...
oven are avoided by use of this process. This means that any issue of moisture sensitivity
Moisture Sensitivity Level
Moisture Sensitivity Level relates to the packaging and handling precautions for some semiconductors. The MSL is an electronic standard for the time period in which a moisture sensitive device can be exposed to ambient room conditions ....
(MSL) in components by outgassing of moisture is completely avoided. This also then removes the storage equipment and processes needed to keep the moisture levels low in more intricate and expensive chips.
Main disadvantages
Currently though the process is set, it has not yet been implemented. It is defined as a “disruptive technologyDisruptive technology
A disruptive technology or disruptive innovation is an innovation that helps create a new market and value network, and eventually goes on to disrupt an existing market and value network , displacing an earlier technology there...
” requiring a complete change in current manufacturing processes. Therefore cost concerns for manufacturers needing new equipment, labour concerns for current PCB manufactures and others will need to be solved or addressed before widespread adoption of this process.
Although many toxic chemicals are removed from the traditional process, Occam’s increased use of encapsulation by epoxy could mean more of that sort of waste. The usual additives in epoxy have been shown to mimic estrogen possibly resulting in adverse hormonal responses in humans.
Trivia
The name of the process is in reference to a quote by William of OckhamWilliam of Ockham
William of Ockham was an English Franciscan friar and scholastic philosopher, who is believed to have been born in Ockham, a small village in Surrey. He is considered to be one of the major figures of medieval thought and was at the centre of the major intellectual and political controversies of...
(1288 - 1348) who said: “It is vanity to do with more that which can be done with less.”
External links
- Verdant Electronics homepage
- Download link - White Paper on the Occam Process