< img height="1" width="1" style="display:none" src="https://www.facebook.com/tr?id=1724791474554128&ev=PageView&noscript=1" />

IC Test Board: The Ultimate FAQ Guide

Table of Contents

I know you are looking for high quality and reliable IC test board.

A reason this guide explores everything you need to know about IC test board – from design, specification, characteristics to material type, among other critical aspects.

Keep reading to learn more.

What Is An IC Test Board?

An IC Test Board
An IC Test Board

An IC test board is useful in automated integrated circuit testing.

The IC test board is a PCB that connects an integrated circuit to a test head, which then connects to ATE (Automatic Test Equipment).

When using an IC test Board, ensure the board meets the electrical and mechanical requisites of the individual chi.

This also applies to the explicit equipment of test you intend to employ.

You can use an IC test board to test silicon wafer dies before cutting and packaging. It is also possible to employ an IC Test board on already packaged ICs.

What Materials Do You Employ In IC Test Boards?

An IC test board like any other PCB encompasses several material components.

You find the following PCB materials common in such boards:

  • Copper: You laminate the board with copper by applying heat and a bonding agent. The copper plates you employ determine your board’s C description as single-layer, double-layer, or multi-layer.
  • FR-4: FR4 is an epoxy resin laminate with glass reinforcement that is most important and gives the board its stiffness.
  • Silkscreen: As the ultimate layer in a PCB, the silkscreen aids in the assembling process by printing designators and markers.
  • Solder mask: Insulation of the copper traces is possible by employing solder mask which prevent copper from contacting other metal parts.

How Many Layers Can An IC Test Board Have?

You configure IC test boards in layers by laminating them using a bonding agent usually prepreg.

The PCB board arrangement includes a substrate and conductive layer with the top layer having a solder mask and silkscreen.

An IC test board can be single-layer, double-layer or multi-layer. You can furnish an IC test board with over forty layers depending on the application needs.

A 10 Layer IC Test Board
A 10 Layer IC Test Board

What Surface Finishes Are Applicable On An IC Test Board?

PCB surface finish in an IC test board protects the conductive copper from oxidation via exposure to the atmosphere.

Additionally, a surface finish also makes the surface solderable during the assembly process.

Some of the surface finishes you can employ on an IC test board are:

  • Lead Free HASL (Hot Air Solder Levelling) which is widely available and has excellent shelf life.
  • Immersion Tin which provides you with a flat surface and is reworkable.
  • Immersion Silver which is non-hazardous and forms an even surface.
  • ENIG (Electroless Nickel Immersion Gold) which is lead-free, highly uniform and with a long shelf life.

What Are Some Of The Features You Can Have In An IC Test Board?

An IC test board can have several different features depending on the application and devices under test. Some of the features you find in these boards include:

  • Exposed technology for inner layers to meet information transmission requirements where you use your IC test boards for high frequency circuits.
  • Layer counts that can reach 64 with board thickness to hole diameter ratio of 16:1.
  • High-precision technique for back-drilling to minimize equivalent series inductance and meet the standards for product integrity.
  • Modern anti-CAF technology that considerably increases the reliability and useful life of IC test boards.
  • Advanced thick copper production to accommodate high heat dissipation needs of high power applications.
  • Precision control of high-density traces to suit the requirements of photoelectric communication product design.
  • Advanced buried technology for capacitors and resistors ensuring product dependability.
  • High-precision technology in relation to mechanical aspects and laser depth control allowing attainment of various assembly needs.
An IC Test Board Comes With Various Features
An IC test Board Comes WIth Various Features

Standards are technical specifications alongside other precise details that you apply consistently in specific activities as guidelines or rules.

In employing standards, you improve the reliability and efficiency of products.

Standards also streamline industry activities ensuring products meet a common threshold of quality assessment.

When using standards, you improve the general product safety thereby decreasing the likelihood of accidents.

What Are Some Of The Equipment You Utilize In Making IC Test Boards?

Different Modern Equipment Are used In The Manufacture Of Integrated Circuit Test Board

Manufacture of IC test boards includes several modern equipment allowing for increased efficiency and productivity. These include:

  • Plasma processing machine for degumming of PTFE hole walls, ceramic fillers and high-frequency materials.
  • Automatic Optical Inspection (AOI) machine for inspecting high-precision circuits.
  • Testers for hole copper, ion staining, copper thickness, secondary element, anti-stripping strength and other reliability equipment for ensuring high product quality.
  • Laser Direct Imaging (LDI) machine for high-precision circuits’ graphics transfer.
  • CNC drilling equipment and molding machine you employ in deep hole control and back drilling and deep groove milling respectively.
  • A high-precision impedance tester for meeting the test requirement for impedance.

What Factors Do You Consider When Designing An IC Test Board?

The IC test board is at the heart of the testing process and producing a highly accurate one is essential.

It is therefore important to factor in various elements for your IC test board design as follows:

  • Electrical design considerations including tester specifications, chip package and test socket characteristics.
  • The IC package you need to test.
  • The test sockets for interfacing with the integrated circuit package and installation process.
  • The different test heads you can connect the IC test board to.
  • Whether your IC test board needs peripheral circuit components such as relays, resistors, or capacitors.
  • The automated handling equipment that you employ.
  • Whether you will dock the IC test board to a thermal equipment or device handler.
  • The functional and operational aspects of the standard setup.
There Are Numerous Factors To Consider During Design
There Are Numerous Factors To Consider During Design

How Do You Design An IC Test Board?

The design spec composes the first step in the process of designing and creating an IC test board.

The design spec is the document that covers the majority of the design considerations related to electrical and mechanical features.

You find most test settings involve some special configuration, thus, it is critical to investigate any specific requirements.

You generate the IC test board layout using the design requirement information.

Computer-aided design automatically develops the layout upon completion of component placement.

You, however, employ manual routing for crucial signal pathways to boost density and decrease signal degradation.

CAD has the advantage of conducting a comprehensive layout.

Manual procedures, however improve board performance by managing impedance, matching differential pairs, reducing signal loss and minimizing transitions.

You can model and simulate the fixture design by employing a mechanical CAD application.

To fabricate the IC test board, and fixture, you directly supply the developed CAD models to CAM (Computer-Aided Machines).

What Is The Test Interface Unit In Relation To An IC Test Board?

You refer to the interface between the device under test, tester, and handler as the test interface unit.

It consists of a contactor that keeps the device under test to the IC test board.

You note that a mechanical fixture secures the device under test to the head of the IC test board.

You independently test the component elements before assembly to form the test interface unit.

It is important to perform another test after assembly to ensure that the integrated unit performs as expected.

You ensure proper mechanical fit and electrical performance by testing the entire test interface unit assembly.

A device simulator and a manual actuator allow you to perform the test on a simulated test-head fixture. You save time and money in evaluating the performance of a test interface unit due to its high cost.

What Parameters Can You Measure Using An IC Test Board?

An IC test board is a useful tool that allows you to acquire circuit node access and measure component performance.

Some of the parameters you can measure using an IC test board includes capacitance and resistance.

You can also functionally measure digital circuits but it is a difficult process that makes no economic sense.

An IC test board can ensure confirmation of your board construction to a correctness level with the capacity to meet its specifications.

What Elements Constitute An IC Test Board?

An IC test board has several elements that it utilizes in running the test program and accessing the circuit’s required points. These elements include:

  • Controller: The controller is the part of the IC test board that directs everything.
  • Fixture: The tester’s contact with the board under test is the fixture which usually contains a bed of nails. You arrange the bed of nails such that you have create connection to the circuit’s required nodes.
  • Interface: An interface makes it possible to link the board with a range of fittings such as electrical connection. Zero Insertion Force connectors allow you to make an electrical connection while it can also support power and air supply or vacuum.
  • Switch: The switch matrix allows routing of the measurement system elements to the correct test location.
Fig 6- There Are Many Elements That Constitute An IC Test Board
There Are Many Elements That Constitute An IC test Board

What Is The Fault Coverage Of An IC Test Board?

You can achieve a fault coverage of up to ninety eight percent when employing an IC test board.

While it may be unachievable at times, it is ideal where you have total node access.

Where you have low-value capacitors the test system’s spurious capacitance sometimes prevents accurate measurement of low-value capacitance.

Inductors have a similar problem, however, having a component in place makes it achievable due to low resistance.

Where there is difficulty in accessing all board nodes, more complications arise. You can attribute this to a lack of capacity on the tester’s part, or component obstruction of an access point.

In this case you can apply implied testing, where you test a bigger circuit portion with numerous components as a unit.

While you can achieve overall confidence in the circuit, it is much less considering the increased difficulty in finding defects.

What Are The Advantages Of Using An IC Test Board?

An IC test board offers you a number of benefits and drawbacks.

When deciding on the optimum board type of a given application, it’s important to weigh its benefits and drawbacks.

You find the following advantages in employing an IC test board:

  • Easily discover manufacturing defects: Many board errors result from manufacturing issues. These include incorrect component value and insertion, wrong attachment of diodes and transistors, shorts and and open circuits.
  • An IC test board can discover these defects easily by evaluating components, continuity, and other factors.
  • Easy interpretation of test results: You can easily locate an issue on the board. It signals a specific node with a short or open, or a faulty component without requiring highly qualified personnel.
  • Easy to programme: You can programme an IC test board by employing the files you derive from the design layout.
  • Increases reliability: The ICT fixture’s huge number of wires presents a point of failure since they’re prone to breakage and disconnection. Using an IC test board with wireless fixtures greatly improves reliability.
  • Limits spurious resistance: ICT fixture cables are long to ensure proper opening and closing of the fixture. You can have a substantial resistance amount due to the cable lengths, lowering the system’s total measurement accuracy.
  • Lowers fixture production costs: Employing contemporary software, you can lower fixture production costs by using an IC test board. Automatic track routing in the board design ensures the fixture’s intricate wiring isn’t included in the manufacturing process.
  • Reduces fixture complexity: Most IC testing fixtures requires numerous wires to link the various probes to the main connector. Working with these many wires is complex and exhausting.

What Drawbacks Do You Associate With An IC Test Board?

You note the following disadvantages in employing an IC test board:

  • Difficulty in accessing nodes: As the boards shrinks, nodes access is more challenging requiring special contact points rarely available due to miniaturization. You can have nodes without any contact points at all complicating IC test boards and limiting the achievable fault coverage.
  • Expensive fixtures: The fixtures might be expensive since they’re mechanical requiring general and wire assembly for each board.
  • Updating fixtures is difficult: Being fixed mechanical objects with mechanically fastened probes, board changes affecting contact point position are costly.

Where Can You Employ The IC Test Board?

You Can Find IC Test Boards Used In Various Machines

You Can Find IC Test Boards Used In Various Machines

You can have different IC test board for use in several applications depending on the volume, testing method, and board type.

Some of the machines you find the IC test board include:

  • Cable-form tester: You use this tester in testing cables with the employment of high voltages at times for insulation tests.
  • Flying probe tester: Constructing and manufacturing an entire bed-of-nails test fixtures is complex and expensive. As such, replacing component positions or moved tracks is challenging requiring use of flying probes.

A flying probe holds the board in place by utilizing a basic fixture with contact created by movement around the board. You can control these movements by using software which you can update accordingly.

  • ICT machine: Includes machines competent enough to perform measurements of basic resistance and continuity in addition to capacitance and device functionality.
  • Manufacturing Defect Analyzer (MDA): You perform basic in-circuit resistance, insulation, and continuity test using this tester. The sole objective of this tester is to detect manufacturing flaws such as shorts related to tracks and open circuit paths.

What Are Driver Sensors In IC Test Boards?

The active circuits you employ in making test measurements are the driver-sensors.

In an IC test board, you have pairings of drivers and sensors.

Drivers provide a voltage or current allowing a node transfer to a specific state.

They possess sufficient capability to transfer the node regardless of the state of the adjacent circuitry.

You can have driver sensors forcing an IC test board’s output to a specific state despite the device’s native output state.

You have to keep the driver’s output impedance extremely low to execute this.

Sensors allow you to take the measurements employing high impedance to avoid interfering with the monitored circuit.

Why Is Guarding An Important Technique When Using An IC Test Board?

Guarding is a technique that is crucial to the success of testing using an IC test board.

When a component is absent in a circuit, it is fairly simple to determine its value.

For instance, you can easily determine a resistor’s value by using an ohmmeter.

It is different with a circuit component since surrounding paths can change measured value.

Guarding overcomes this problem and obtains a significantly more accurate representation of the component’s value.

You earth the nodes surrounding the component under test, removing any leakage routes and allowing for more precise readings.

How Is Multiplexing Essential In IC Test Boards?

Printed circuit boards are becoming increasingly complex with larger boards accommodating up to thousands of nodes.

Each individual node requires a driver sensor and therefore, having separate pins for every node is exorbitant.

Multiplexing is a technology that you employ to prevent the need of having individual pins for each nodes.

In this case, you employ a switching matrix for node routing to accommodate multiple nodes with a primary node.

You define a multiplex ratio which refers to the amount of nodes addressed by the primary node of an IC test board.

However, while it reduces costs, implementing multiplexing limits the tester’s flexibility.

You can only access one multiplexed node at a time which can result in programming and fixture limitations.

You have to carefully consider the fixture construction to guarantee no simultaneous need of a pin pairing in a multiplex route.

Automatically assigning the pins using software you employ in generating the test program and fixture wiring schematic can cause issues.

It is prudent to inquire on the use of multiplexing in your machine and the ratio.

You can then make an informed decision whether to go for cost savings at the expense of flexibility loss.

For all your IC test boards, contact Venture Electronics now.

Recent Posts
Contact Us
Send A Message