Circuit Board Industry Research Articles

A study of critical processing technologies of liquid crystal polymer printed circuit board for high speed application

AbstractRecent demand for high‐frequency and high‐speed signal transmission over GHz is driving the printed circuit board (PCB) industry towards a more advanced material‐based era. To meet this market demand, liquid crystal polymer (LCP) has been suggested for its predominant material characteristics, such as high temperature resistance, low moisture absorption and excellent dimensional stability. However, former experimental and theoretical studies on the fabrication technology for processing the LCP PCB at different treatment conditions are lacking. This article thus evaluates the recent development of LCP PCB process technology. Different process approaches involving in lamination, drilling, desmearing, and metallization are proposed and compared, and associated reliability testing is addressed. Experimental results are shown to demonstrate the efficacy of the proposed approach for developing the process technology of LCP PCB. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

A Novel Nitric Acid Etchant and Its Application in Manufacturing Fine Lines for PCBs

We have developed a new etching solution for the printed circuit board industry. The primary oxidant of the solution is nitric acid, which reacts with copper coating on the substrate. The other components of the solution are sulfuric acid and additive, which are used to control etching reaction rate and solution's characteristics. The optimum parameters for the concentrations of nitric acid, sulfuric acid, additive, and the operating temperature were obtained through orthogonal experiment with stagnant etching method. The parameters were then verified by the spray etching experiment in the industrial production line. Then, there are a series of tests, carried out by metallographic slicing tester and scanning electron microscopy to evaluate the quality of copper conductive lines in stagnant and spray etching experiments. compared with conventional cupric chloride etchant, the testing results showed that the nitric acid etchant can manufacture fine lines with lower undercut, better wall sides, with higher etching rate, as well as being more friendly to the environment How the addition of H2SO4 influences etching rate and etching mechanism of nitric acid etchant is also discussed.

Data clustering and fuzzy neural network for sales forecasting: A case study in printed circuit board industry

In order to obtain a better control of market trend and profit for the company, timely identification of sales is very important for businesses. Upward and downward trends in sales signify new market trends and understanding of sales trends is important for marketing as well as for customer retention. This research develops a hybrid model by integrating K-mean cluster and fuzzy neural network (KFNN) to forecast the future sales of a printed circuit board factory. Based on the K-mean clustering technique, the historical data can be classified into different clusters. The accuracy of the forecasted model can be further improved by referring the new data to be forecasted from a more focused region, i.e., a smaller region after clustering. Numerical data of various affecting factors and actual demand of the past 5 years of the printed circuit board (PCB) factory are collected and input into the hybrid model for future monthly sales forecasted. The experimental results derived from the proposed model show the effectiveness of the hybrid model when compared with other approaches.

A comparative analysis of the factors affecting the implementation of occupational health and safety management systems in the printed circuit board industry in Taiwan

The certification and implementation of occupational health and safety management systems have become a priority for many organizations. To investigate the status of implementing occupational health and safety management systems (OHSMSs), and to explore important performance indicators for OHSMSs' performance appraisal in the printed circuit board (PCB) industry in Taiwan, a survey was administered to eleven PCB manufacturers, all of which have been certified as compliant to the guidelines on OHSMS of the Occupational Health and Safety Assessment Series (OHSAS) 18001, and to twenty-six OHSAS specialists from the academe. The results of the survey indicated that the implementation of OHSAS 18001 in the PCB industries was motivated externally by customer requirement, and internally by corporate image and top management requirements. The most critical factor for the success of OHSAS implementation was top management's commitment and support while the main reason of its failure was poor collaboration among company personnel. For OHSMSs' performance evaluation, the frequency of unsafe conduct by employees, the level of top management's commitment, the completion rate of corrective and preventive measures, the frequency of subcontractor rule violations and the level of fire-fighting system are significant performance indicators for condition, management and operation aspects.

Measuring production and marketing efficiency using grey relation analysis and data envelopment analysis

The aim of this paper is to measure production and marketing efficiencies in the printed circuit board (PCB) industry using grey relation analysis (GRA) and data envelopment analysis (DEA) techniques. A total of 32 efficiency indicators are initially considered and seven are selected. They represent five indicators for production efficiency and two for marketing efficiency. Fifteen of the 23 companies evaluated need improvement in both production and marketing efficiencies, while four companies had their priority production efficiency improvement and the remaining four companies with priority in marketing efficiency improvement.

A particle swarm optimization approach for components placement inspection on printed circuit boards

The importance of the inspection has been magnified by the requirements of the modern manufacturing environment. In electronics mass-production manufacturing facilities, especially in the printed circuit board (PCB) industry, 100% quality assurance of all work-in-process and finished goods is required in order to reduce the scrap costs and re-work rate. One of the challenges for PCB inspection is in the use of a surface mount device (SMD) placement check. Missing, misaligned or wrongly rotated components are the critical causes of defects. To prevent the PCB from having these defects, inspection must be done before the solder reflow process commences, otherwise, everything will be too late. The research reported in this paper concentrates on automatic object searching techniques, in a grey-scale captured image, for locating multiple components on a PCB. The presented approach includes the normalized cross correlation (NCC) based multi-template matching (MTM) method. The searching process has been carried out by using the proposed accelerated species based particle swarm optimization (ASPSO) method and the genetic algorithm (GA) approach as a reference. The experimental results of the ASPSO-based MTM approaches are reported.

Efficiency measures of PCB manufacturing firms using relational two-stage data envelopment analysis

Taiwan is currently the fourth largest contributor to the printed circuit board (PCB) industry. In exploring the operation activities of PCB industry, most studies focuses primarily on manufacturing or production technologies. In this paper, we evaluate the performance of PCB manufacturing firms in Taiwan. Since the whole production process of the manufacturing firms can be divided into two sub-processes: production acquisition and profit earning, this study employs the relational two-stage DEA approach, which takes into account the series relationship of the two sub-processes within the whole process, to decompose and measure the efficiencies of the manufacturing firms. It is found that none of the manufacturing firms perform efficiently both in the stage of production acquisition and the stage of profit earning. In addition, the low efficiency score of the whole production process is mainly due to the low efficiency score of the profit generating process. To improve productivity and profitability, the manufacturing firms need to consider the issues of product improvements and technological innovation in the future.

An ALE Model for Prediction and Control of the Microvia Fill Process with Two Additives

A computational model for examining the microvia fill process as encountered in the multilayered printed circuit board industry is presented. The model includes mass transfer of both copper and the additive species present. The additives’ mass balance is considered between both the solution and the surface-adsorbed layer of additives, as well as on the shape-changing cathode surface where the mass balance of adsorbed additives is affected by the surface shape change and diffusive mass transfer along the surface. The model is implemented as a finite element model applying the arbitrary Lagrange–Eulerian (ALE) method for boundary tracking, and a weak formulation of the mass-balance equations is given to aid numerical solution of the model. Model stability and fitting against experimental data is examined over a range of relevant parameters.

Novel Mercury Oxidant and Sorbent for Mercury Emissions Control from Coal-fired Power Plants

The authors have successfully developed novel efficient and cost-effective sorbent and oxidant for removing mercury from power plant flue gases. These sorbent and oxidant offer great promise for controlling mercury emissions from coal-fired power plants burning a wide range of coals including bituminous, sub-bituminous, and lignite coals. A preliminary analysis from the bench-scale test results shows that this new sorbent will be thermally more stable and cost-effective in comparison with any promoted mercury sorbents currently available in the marketplace. In addition to the sorbent, an excellent elemental mercury (Hg(0)) oxidant has also been developed, and will enable coal-fired power plants equipped with wet scrubbers to simultaneously control their mercury emissions as well as their sulfur oxides emissions. This will work by converting all elemental mercury to an oxidized form which will be removed by the wet scrubber. This will result in significant cost savings for mercury emissions control to the atmosphere, and will help in keeping electric costs low. The sorbent and oxidant will benefit from the utilization of a waste stream from the printed circuit board (PCB) industry, and would thus be environmentally beneficial to both of the utility and electronics industries. The sorbent also demonstrated thermal stability up to 350°C, suggesting a possibility of an application in pulverized coal-fired power plants equipped with hot-side electrostatic precipitators and coal gasification plants.

A Copper Removal Process for Printed Circuit Board Wastewater Sludge Applying Extraction and Cementation with Chelating Agents Recovery

Removal of copper from printed circuit board (PCBD) industry wastewater sludge by chelant extraction and subsequent cementation by powdered irons were studied. Aqueous chelant solutions of 0.1 M ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) were used to treat sludge from three PCBD factories. Copper that was extracted from these sludge sources by the chelating agents ranged in concentration from 0.72 to 0.81 mol Cu mol−1 EDTA, to 0.57 to 0.80 mol Cu mol−1 DTPA. Competition from other major metal cations in the sludge sources for active sites on chelating agents may contribute to observed differences in copper extraction efficiencies. After extraction with chelating agents, powdered irons were used to replace the chelated copper in the chelant extract, allowing for copper recovery. The recovery efficiencies of copper by the cementation process using powdered iron were 92–99%. After cementation, the extract containing EDTA or DTPA was reused to chelate supplementary fresh copper-containing sludge once again. Recovery ratios of copper from the supplementary sludge were 23.7–100.0%, in comparison with that obtained in previous extraction. Similar copper removal efficiencies observed in the use of both pristine and reused chelant extracts indicate that EDTA and DTPA have enduring chelating capability, and suggest the recycling of chelating agents to reduce overall process usage. This work demonstrated the feasibility of copper removal and recovery from some PCBD wastewater sludge (Sludge B) by chelant extraction and subsequent cementation.

A fuzzy case-based reasoning model for sales forecasting in print circuit board industries

Reliable prediction of sales can improve the quality of business strategy. Case-based reasoning (CBR), one of the well known artificial intelligence (AI) techniques, has already proven its effectiveness in numerous studies. However, due to the uncertainties in knowledge representation, attribute description, and similarity measures in CBR, it is very difficult to find the similar cases from case bases. In order to deal with this problem, fuzzy theories have been incorporated into CBR allowing for more flexible and accurate models. This research develops a fuzzy case-based reasoning (FCBR) and explores its potential use in supporting a forecaster during the forecast process for forecasting the future sales of a printed circuit board factory. Numerical data of various affecting factors and actual demand of the past 5 years of the printed circuit board (PCB) factory are collected and input into the FCBR for future monthly sales forecasting. Experimental results show the effectiveness of the FCBR model when comparing it with other approaches.

Multifactor performance measure model with an application to printed circuit board industry

The research described in this paper contains two parts. The first part is to present an empirical investigation where financial index is considered to measure the printed circuit board performance. The second part is to examine the effects of financial index on sales and gross margin. The technique of Data Envelopment Analysis is utilised to derive the efficiency and multiple regression analysis to disclose the effects. There were remarkable results: (1) the averaged efficiency was 0.746 which, generally speaking, did not show a good performance, (2) PCB manufacturers in the group of Single-Sided Boards/Double-Sided Boards and Multi-Layer Boards manufacturers performed average efficiency was 0.7784, (3) PCB manufacturers in the group of Flexible Print Circuit (FPC) performed average efficiency was 0.8492, (4) current assets, the number of employees and operating expenses showed significant effects on both the sales and gross margin. Other research findings were addressed and discussed in this research also.

Technology and application of electro-depositable photo resists to create uniform coatings needed for complex 3D micro actuators and sensors

Electro-depositable photo resists, which have been developed for printed circuit board industry (PCB), are recently receiving great attention in MEMS technology. This paper reports on the technology needed and its application for patterning 3D microstructures with high aspect ratios and large structure heights. Adapted equipment for coating structured and non-structured wafers is introduced. The optimized process technology obtained by a multitude of parameter variations is described—providing the application engineer with a means to produce pin hole free uniform coatings on arbitrary geometries, which may be structured with high resolution and allow high aspect ratios. The technology was adapted to several applications, which show the big potential for the development of micro actuators and sensors. This paper focuses on the utilization for electroplating conductors, which are part of a micro actuator based on a helical coil.

Recovery of copper and chelating agents from sludge extracting solutions

Removal of extraction solution containing chelated copper from printed circuit board industry sludge by cementation on powdered iron was studied. This work applied the recovery and extraction of ethylene diamine tetraacetate (EDTA) and diethylene triamine pentaacetate (DTPA) as remediation agents and metal precipitated from printed circuit board sludge extracting solutions. The recovery of copper by cementation process using powdered iron was dependent on the Fe:Cu molar ratio. Results of the experiments showed that recovery efficiencies were typical of those of a Fe:Cu molar ratio as high as 8:1 for each sludge sample. The differences of recovery efficiencies may be due to competition for active sites on the surface of the powdered iron. Copper deposits on the surface almost always occur in the form of the copper metal that are well distributed, with purified copper powder being observed in characterization with scanning electron microscopy (SEM) and X-ray powder diffraction (XRD). The recycled extract containing EDTA or DTPA was used to chelate supplementary fresh copper-containing sludge. Extraction efficiencies of copper by using Fe-precipitated EDTA or DTPA from previous cementation were higher than sequential application of the Fe-EDTA or Fe-DTPA solution. Similar copper extraction efficiencies using both pristine and reused extract containing chelants validates the enduring chelating capability of EDTA and DTPA and suggests further opportunities to employ recycled chelant to reduce its usage. This work confirmed the feasibility of copper removal from sludge chelated wastewater by cementation and subsequent recycling of chelant extraction.

Adaptive multi-objective genetic algorithms for scheduling of drilling operation in printed circuit board industry

In this paper, a scheduling problem for drilling operation in a real-world printed circuit board factory is considered. Two derivatives of multi-objective genetic algorithms are proposed under two objectives, i.e. makespan and total tardiness time. The proposed algorithms possess a rare characteristic from traditional multi-objective genetic algorithms. The crossover and mutation rates of the proposed algorithms can be variables or adjusted according to the searching performance while the rates of traditional algorithm are fixed. Production data retrieved from the shop floor are used as the test instances. The numerical result indicates that both two proposed multi-objective genetic algorithms have satisfactory performance and the adaptive multi-objective genetic algorithm performs better. The result shows the algorithms are effective and efficiency to the current system used in the shop floor. Thus, the result may be of interest to practical applications.

Printed circuit board industry

The printed circuit board is the platform upon which microelectronic components such as semiconductor chips and capacitors are mounted. It provides the electrical interconnections between components and is found in virtually all electronics products. Once considered low technology, the printed circuit board is evolving into a high-technology product. Printed circuit board manufacturing is highly complicated, requiring large equipment investments and over 50 process steps. Many of the high-speed, miniaturized printed circuit boards are now manufactured in cleanrooms with the same health and safety problems posed by other microelectronics manufacturing. Asia produces three-fourths of the world's printed circuit boards. In Asian countries, glycol ethers are the major solvents used in the printed circuit board industry. Large quantities of hazardous chemicals such as formaldehyde, dimethylformamide, and lead are used by the printed circuit board industry. For decades, chemically intensive and often sloppy manufacturing processes exposed tens of thousands of workers to a large number of chemicals that are now known to be reproductive toxicants and carcinogens. The printed circuit board industry has exposed workers to high doses of toxic metals, solvents, acids, and photolithographic chemicals. Only recently has there been any serious effort to diminish the quantity of lead distributed worldwide by the printed circuit board industry. Billions of electronics products have been discarded in every region of the world. This paper summarizes recent regulatory and enforcement efforts.

A hybrid model by clustering and evolving fuzzy rules for sales decision supports in printed circuit board industry

This research develops a hybrid model by integrating Self Organization Map (SOM) neural network, Genetic Algorithms (GA) and Fuzzy Rule Base (FRB) to forecast the future sales of a printed circuit board factory. This hybrid model encompasses two novel concepts: (1) clustering an FRB into different clusters, thus the interaction between fuzzy rules is reduced and a more accurate prediction model can be established, and (2) evolving an FRB by optimizing the number of fuzzy terms of the input and output variables, thus the prediction accuracy of the FRB is further improved. Numerical data of various affecting factors and actual demand of the past 5 years of the printed circuit board (PCB) factory are collected and inputted into the hybrid model for future monthly sales forecasting. Experimental results show the effectiveness of the hybrid model when comparing it with other approaches. However, the theoretical development of the validity of clustering an FRB into sub clusters remains to be proven.

The influence of curing systems on epoxide‐based PCB laminate performance

PurposeThere are many considerations that have to be taken into account when balancing the properties epoxy‐based laminate and prepreg materials must have in order to meet the array of electrical, thermal and mechanical demands of today's multilayer printed circuit boards. Aims to discuss two different curing systems that are commonly employed in current laminate and prepreg materials.Design/methodology/approachAn examination of the two different curing systems – phenol novolac (PN) and dicyandiamide (DICY) based – that are commonly employed in current laminate and prepreg materials.FindingsDICY curing systems have properties such as good flexibility, good adhesion and good processability but have poor thermal resistance, higher water absorption and poor anti‐CAF capability. Because PN resin systems utilize an aromatic ring structure, traditional PN cured epoxy resin results in having excellent thermal resistance, low water absorption and anti‐CAF capability.Originality/valueProvides a comparison of interest to all those involved with laminate and prepreg materials in the circuit board industry.

Digital printing for printed circuit boards

PurposeTo review opportunities for use of digital printing in the printed circuit board (PCB) industry and to introduce background to ink jet printing, process development and applications in order to reduce costs, enhance efficiency and to enable PCB producers to operate in a more sustainable and flexible manner.Design/methodology/approachThis paper has been written to provide a review of ink jet printing applications in the PCB industry. Ink jet print technology background, ink development and the processes made possible by ink and print head improvements have been described together with a description of the benefits available through digital printing.FindingsIt was found that there have been significant developments over recent years in both hardware technology (print heads and accurate print platforms) as well as improvements in the design of inks both for ink jet print performance and functional characteristics. These improvements have been integrated to provide an exciting new technology which can be applied in the manufacture of PCBs to reduce manufacturing costs and increase flexibility of manufacture.Originality/valueThe value of the paper lies in its ability to provide information on the scope of opportunities for ink jet printing in the PCB manufacturing process through the use of a range of new inks having specific properties. The design and development of highly accurate machinery provides the opportunity to attain the desired print resolution.

Chemical preparation of Pd nanoparticles in room temperature ethylene glycol system and its application to electroless copper deposition

Room-temperature synthesis of Pd nanoparticles protected by polyvinylpyrrolidone (PVP) has been successfully achieved by merely adding sodium hydroxide (NaOH) acting as accelerator for the reduction of Pd(II) in ethylene glycol (EG) without any externally added reducing agent. The Pd particle sizes were controlled in the range from 8.6 to 2.4 nm by changing the concentration of NaOH from 0 to 3.2 × 10 −1 M . The particle formation was monitored by UV–vis spectroscopy and the microstructure of Pd nanoparticles was analyzed by TEM and XRD. The product of adding NaOH in EG was characterized by FTIR and a CHO group which possesses reductive ability was identified. In addition, the prepared Pd nanoparticle could serve as an effective activator for electroless copper deposition (ECD) on epoxy substrate, which is an essential process in the printed circuit board (PCB) industry. In contrast to existing commercial activators, the new activator shows superior stability and excellent performance for ECD.