Integrated Circuit Board Research Articles

A Soldering Defect Inspection System of a Special Integrated Circuit Board Based on Computer Vision

This paper introduces a soldering defect inspection system for a special integrated circuit board aided by the computer vision. Space occluder is fixed on this special integrated circuit board, which makes the light blocked from the CCD camera to the chip pins to be inspected. This system can inspect the light blocked soldering defects of the chip pins through the structure design of hardware system and the software system. It is a cheap but automatic soldering defect inspecting system, and can do the soldering defect detection instead of manual visual inspection, and improve the detection speed and stability.

Calibration method of projection coordinate system for X-ray cone-beam laminography scanning system

Computed laminography (CL) is different from conventional computed tomography(CT) for its specialization in testing plate-type structures, such as integrated circuit boards (ICB), multilayer printing circuit boards (MPCB), and ball grid arrays (BGA). It adopts a different scanning way to successfully produce cross-sectional images of the plate-type objects, while the conventional CT cannot be used. According to the CL reconstruction algorithm, precise determination of the origin of the projection coordinate system is the first step during cone-beam CL scanning system calibration. But unfortunately, for the practical CL scanning system, it is impossible to measure the position of the X-ray focus projection by direct means. A new method to determine the X-ray focus projection coordinates with high accuracy is proposed. Firstly the angle between the central X-ray and the axis of rotation is set to zero by rotating the X-ray source and detector synchronously. Acquiring digital radiography (DR) images of several spherical objects at two geometrical magnification ratio positions in the cone X-ray beam, the two DR images are combined to one image, on the base of which image processing methods are employed to get the center points of each projection of the spherical object. And every two-positioned center points of the same spherical object determine a line, so all couples of projection centers of all the spherical objects construct a group of lines, mathematically an over-determined equation set. After solving the over-determined equation, the X-ray focus projection coordinates are finally obtained. The experimental results prove that the accuracy of this method can satisfy the requirements of the practical scanning system, meanwhile it is feasible to realize.

Control System Design of the YWZ Multi-Fingered Dexterous Hand

The manipulation abilities of a multi-fingered dexterous hand, such as motion in real-time, flexibility, grasp stability etc., are largely dependent on its control system. This paper developed a control system for the YWZ dexterous hand, which had five fingers and twenty degrees of freedom (DOFs). All of the finger joints of the YWZ dexterous handwere active joints driven by twenty micro-stepper motors respectively. The main contribution of this paper was that we were able to use stepper motor control to actuate the hand's fingers, thus, increasing the hands feasibility. Based the actuators of the YWZ dexterous hand, we firstly developed an integrated circuit board (ICB), which was the communication hardware between the personal computer (PC) and the YWZ dexterous hand. The ICB included a centre controller, twenty driver chips, a USB port and other electrical parts. Then, a communication procedure between the PC and the ICB was developed to send the control commands to actuate the YWZ dexterous hand. Experiment results showed that under this control system, the motion of the YWZ dexterous hand was real-time; both the motion accuracy and the motion stability of the YWZ dexterous hand were reliable. Compared with other types of actuators related to dexterous hands, such as pneumatic servo cylinder, DC servo motor, shape memory alloy etc., experiment results verified that the stepper motors as actuators for the dexterous handswere effective, economical, controllable and stable.

The Steiner ratio for points on a triangular lattice

The study of spanning trees and Steiner trees arises naturally in applications, such as in the design of integrated circuit boards, communication networks, power networks and pipelines of minimum cost. In such applications the Steiner ratio is an indication of how badly a minimum spanning tree performs compared to a Steiner minimal tree. In this paper a short proof is presented for the Steiner ratio for points on a triangular lattice in the Euclidean plane. A Steiner tree in two dimensions is lifted to become a rectilinear tree in three dimensions, where it is altered. The rectilinear tree is then projected back into the plane and the result readily follows. A short note at the end of the paper compares our three-dimensional rectilinear trees to impossible objects such as Escher's Waterfall.

Mechatronic integration and implementation of in situ multipoint temperature measurement for seafloor hydrothermal vent

In order to provide firsthand reference data for model building and analysis of temperature field of seafloor hydrothermal vent, a temperature measurement system is designed, which can be used to measure the temperature of seafloor hydrothermal vent. The system can implement in situ multipoint temperature measurement and work for 15 days on the seafloor, so low power consumption design principle of the integrated circuit board is adopted. To enable the system to endure the high pressure on the seafloor, mechanical structure of the system is designed in terms of design principle of pressure container. The pressure test experiment was performed in the authoritative institution, and the results indicated that the system was safe and could work reliably on the seafloor. In the first Sino-American Joint Dive Cruise, the instruments were carried to the seafloor to work by Alvin. The experiment in the sea was successful, and the results indicated that the system could survive in the high pressure and high temperature environment and record the temperature activities of hydrothermal vents. About 710000 groups of temperature data were acquired, and these are of importance for further scientific researches.

Pyrolysis characteristics of integrated circuit boards at various particle sizes and temperatures

A pyrolysis method was employed to recycle the metals and brominated compounds blended into printed circuit boards. This research investigated the effect of particle size and process temperature on the element composition of IC boards and pyrolytic residues, liquid products, and water-soluble ionic species in the exhaust, with the overall goal being to identify the pyrolysis conditions that will have the least impact on the environment. Integrated circuit (IC) boards were crushed into 5–40 mesh (0.71–4.4 mm), and the crushed particles were pyrolyzed at temperatures ranging from 200 to 500 °C. The thermal decomposition kinetics were measured by a thermogravimetric (TG) analyzer. The composition of pyrolytic residues was analyzed by Energy Dispersive X-ray Spectrometer (EDS), Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In addition, the element compositions of liquid products were analyzed by ICP-AES and ICP-MS. Pyrolytic exhaust was collected by a water-absorption system in an ice-bath cooler, and IC analysis showed that the absorbed solution comprised 11 ionic species. Based on the pyrolytic kinetic parameters of TG analysis and pyrolytic residues at various temperatures for 30 min, the effect of particle size was insignificant in this study, and temperature was the key factor for the IC board pyrolysis. Two stages of decomposition were found for IC board pyrolysis under nitrogen atmosphere. The activation energy was 38–47 kcal/mol for the first-stage reaction and 5.2–9.4 kcal/mol for the second-stage reaction. Metal content was low in the liquid by-product of the IC board pyrolysis process, which is an advantage in that the liquid product could be used as a fuel. Brominate and ammonium were the main water-soluble ionic species of the pyrolytic exhaust. A plan for their safe and effective disposal must be developed if the pyrolytic recycling process is to be applied to IC boards.

Development of a Surface Acoustic Wave Sensor for In-Situ Monitoring of Volatile Organic Compounds

This paper describes the development of a surface-acoustic-wave (SAW) sensor that is designed to be operated continuously and in situ to detect volatile organic compounds. A ruggedized stainless-steel package that encases the SAW device and integrated circuit board allows the sensor to be deployed in a variety of media including air, soil, and even water. Polymers were optimized and chosen based on their response to chlorinated aliphatic hydrocarbons (e.g., trichloroethylene), which are common groundwater contaminants. Initial testing indicates that a running-average data-logging algorithm can reduce the noise and increase the sensitivity of the in-situ sensor.

CONJUGATE HEAT TRANSFER ANALYSIS FOR THE PASSIVE ENHANCEMENT OF ELECTRONIC COOLING THROUGH GEOMETRIC MODIFICATION IN A MIXED CONVECTION DOMAIN

A two-dimensional model has been developed for numerical prediction of viscous laminar flow, mixed convection, and conjugate heat transfer between parallel plates with uniform block heat sources and with openings on the integrated circuit board. A control volume pressure-based finite difference numerical scheme, PISO, is used to solve this problem. The differential pressure below and above the openings of the board induces upward streams, which break the stagnant region between the blocks and, consequently, enhance the heat dissipation. Geometrically, parametric study has indicated that an opening at the appropriate location makes a flatter temperature distribution and a lower peak temperature. Because of the existence of both natural convection and opening-induced passive flow streams, the resulting flow field depends on the inlet conditions and the magnitude of the heat source. The enhancement of heat transfer is reflected by a global increase of Nusselt number on the blocks, and is especially apparent on the wind sides of the openings.

The front end of new product development: a Canadian survey

Despite the importance of the early stages of a product's life, very little attention has been paid to empirically testing the activities performed in the front end of new product development. This article presents the results of a survey of 53 individuals from fifteen high technology firms in the integrated circuit board industry. Our study adopts Cooper's (1988) ‘predevelopment’ model consisting of idea generation, product definition and project evaluation stages, and probes the activities undertaken in each stage. Particular activities were found to play pivotal roles in achieving the objectives of each stage. The results present a clarified view of front end activities that can be used as a starting point for adequately preparing products for development and market success.

The role of predevelopment activities and firm attributes in new product success

The product development literature focuses largely on improving the efficiency and success rates of the development process, while largely neglecting the activities that comprise the predevelopment stages. The result is that little is known about how or why predevelopment practices differ among firms. Our study of fifteen firms in Ontario's integrated circuit board industry revealed interesting differences in predevelopment practices that directly affected the likelihood of new product success. It was revealed that firm size, age, and R&D intensity were significant predictors of predevelopment practices. In addition, activities were identified that serve as a prescriptive guide for the successful development and market launch of new products.

Tests and measurement

Fuelled by worldwide semiconductor sales, the test and measurement industry in 1995 enjoyed a year like few others in living memory. This paper presents an overview of test and measurement technologies and highlights: industry searches for the best testability strategy; methods to probe dense integrated circuit boards and wafers; standard approval for a system-level test bus; and how the equipment community is tackling software testing.

Examination of Various Soldered Surfaces and Electronic Components by Confocal Microscopy

The unique advantages of confocal microscopy are used to explore four cases of interest: (i) voids in solder (depth and surface texture determined), (ii) steam vs ambient aged solder coupons (significant differences detected), (iii) integrated circuit construction (sub‐surface contamination by µm‐size particles observed) and (iv) circuit boards and solder pads (non‐destructive optical sectioning through no‐wash flux layers). It is shown that confocal microscopy strongly complements SEM (scanning electron microscopy); SEM alone presents an incomplete description of a solder surface and in fact can sometimes produce misleading results.

Performance of high resolution silicon pad detector and associated preamplifier circuit board

The performance of a silicon pad detector was tested at room temperature. Energy and time resolution were measured using different types of preamplifiers. An integrated circuit board was designed to handle a 20 element silicon pad detector (2×10). The results show that an energy resolution of about 6.7 keV for 320 keV electrons and a time resolution of 3.6 ns have been achieved at room temperature.

An expert system for integrated circuit board inspection

This paper describes an expert system for defect location in an integrated circuit board assembly. The expert system known as bites (Board Inspection and Training Expert System) is designed with two purposes: (1) automation of the inspection process performed by groups of inspectors or quality control technicians; and (2) for use as a training tool for new inspectors.

Development of a knowledge-based decision support system for diagnosing malfunctions of advanced production equipment

SUMMARY This paper presents a case study documenting the development of an expert system for diagnosing the malfunctions of a machine used by the NEC Corporation to mount chips on integrated circuit boards. Development of the expert system was justified by the inability of operators to efficiently diagnose many malfunctions of the chip-mounting machine, the associated cost of production delays, and the disruption incurred when experts were forced to leave unrelated tasks to help operators troubleshoot malfunctions. The first step in development of the expert system was to elicit and organize the machine designer's knowledge. This process resulted in a hierarchical classification of malfunction symptoms and causes, a set of 15 flow diagrams documenting the designer's troubleshooting procedures for particular malfunction symptoms, and a matrix documenting design information. The flow diagrams were translated into a large logic network diagram, which was directly translated into a set of 94 rules. An additio...

4830622 Integrated circuit socket and board

4830622 Integrated circuit socket and board

4830622 Integrated circuit socket and board

Radiation impact of the SPEs on board the MIR space station and in the interplanetary space is discussed in the report. The data of the on-board radiation dosimeter R-16 were used to measure the SPE absorbed doses. Some of SPEs (such as September–October 1989 series of very large SPEs) were measured in detail by Liulin active high sensitive dosimetric instrument installed on board MIR station. MIR station orbit measurements of the absorbed doses are compared with the interplanetary absorbed doses from SPEs estimated by the data obtained by the METEOR satellite spectrometer. The equivalent dose beyond the magnetosphere resulting from the September 29, 1989 solar flare in a spacecraft module with ordinary shielding thickness (∼10 g/cm2 of Al) is far higher than the maximum permissible dose of acute single exposure (50 cSv) and comparable with the maximum permissible dose of 2 year mission (118 cSv). Such large SPEs are a serious hazard in interplanetary missions and call forth of special administrative countermeasures.

Use of on-line computers in experimental psychology: Hardware considerations

A series of modules provide students with the basic skills to set up and use a computer to run psychological experiments. The modules include basic knowledge of AC/DC power supplies, relay switching, analog/digital conversion, integrated circuit board design and soldering, and elementary programming (FORTH and BASIC). These skills are then utilized to build an interface board and to design and run actual on-line experiments. The hardware orientation is combined with computer skills and experimental methodology to allow students to experience all stages of modem psychological experimentation.