What is probe card used for?
A probe card is a jig used for electrical testing of an LSI (large-scale integrated circuit) chip on a wafer during the wafer test process in LSI manufacturing.
A probe card is docked to a wafer prober to serve as a connector between the LSI chip electrodes and an LSI tester as a measuring machine.
How are probe cards made?
During silicon production, several integrated circuits are located onto a semiconductor wafer.
This wafer is then diced and packaged and shipped out. … The probe card is mounted onto a prober and then connected to a tester in order to create an electrical path between the semiconductor wafer and the tester.
What is advanced probe card?
An advanced probe card is a probe card using advanced technologies.
It is superior to cantilever-type probe cards in terms of throughput, fine pitch, positioning accuracy, and high frequency.
A probe positioning system is a tool for the positioning of a (hand-held) measuring device, such as an ultrasound transducer in a fixed, predetermined place to the object, such as a patient. The operation of these systems varies from completely manual, to completely automated.
Your Best Probe Card Supplier and Partner
Venture probe card planarity measurements are essential to verify that the probe card plane will match the plane of the wafer. Most commonly probe Z positions are measured electrically, by moving a conductive device in contact with the probe to determine its position.
Venture is a professional probe card supplier in China for over 10 years of experience. We render our valued customers the very great products at the most affordable pricing.
We manufacture the highest quality of probe card with our advanced manufacturing facility, skilled and highly trained engineers.
Your Leading Probe Card Supplier in China
Venture is more than 10 years in the probe card manufacturing industry. Depending on your application, we can manufacture a wide array of probe card to meet your demands.
If you are looking for a reliable and high-quality probe card, Venture is your the right place to count on. We are the top market supplier of probe card in the electronics industries.
Venture probe cards over the past decade have been increasingly required to perform more and more
advanced circuit control such as: switching, multiplexing, and on-board signal generation.
Many of these control circuits complicate or prevent the measurement of individual probes, for
electrical and physical properties.
Our current probe card tool the PrecisionWoRx VX4, provides legacy power channels for backward capability, as well as combo signal/power channels for all other probe card connections.
We manufacture high-end and durable probe card for long-lasting use. We deal with cost-effective probe card which is affordable for everyone and readily available.
Venture will always fulfill your any probe card needs. If you have questions and interests in venture’s probe card or any related products, please don’t hesitate to contact us.
Send us your queries. Our team will give you immediate feedback on your next orders.
Probe Card: The Ultimate FAQ Guide
Before choosing probe card PCB, read this guide.
It has all information you need to know about probe card such as features, design, classification, material, etc.
So, keep reading to learn more.
- What Is A Probe Card?
- How Does A Probe Card Work?
- Can You Employ A Single Probe Card To Test Several DUTs In Parallel?
- What Tests Can You Perform Using A Probe Card?
- What Are The Some Of The Types Of Probe Cards?
- What Are The Advantages Of Employing Cantilever Probe Cards?
- How Can You Classify Ceramic Blade Probe Cards?
- What Are The Parameters Of A Ceramic Blade Probe Card That Influence Performance?
- What Are Some Of The Technical Requirements You Consider When Selecting A Probe Card?
- What Are Bond Pads In Probe Cards?
- What Is The Difference Between Pad Size And Pad Pitch In Probe Cards?
- What Materials Can You Employ In Making Probe Card PCBs?
- What Are The Some Of The Probe Card Design Guidelines?
- What Materials Do You Use For The Probe Card Needle?
- What Factors Should You Consider When Choosing A Probe Card Needle?
- What Is Probe Card Geometry?
- What Are The Parameters For A Probe Card?
- Can You Use High-Temperature Testing For Probe Cards?
- Why Should You Carry Out Cleaning Of Needles In Probe Cards?
- What Causes Accumulation Of Dirt On Probe Cards?
- What Cleaning Methods Can You Employ On Probe Cards?
- How Can You Improve Probing And Testability Of Probe Cards?
What Is A Probe Card?
A probe card is a fixture you employ in the electrical testing of a large-scale integrated (LSI) circuit chip’s wafer.
The probe card provides an electrical path between the wafer circuitry and the tester allowing testing of the circuits.
You find a probe card consists of a printed circuit board alongside metallic contact elements.
How Does A Probe Card Work?
Usually, you put a probe card into a wafer prober, which adjusts the position of the wafer to be tested. This ensures accurate contact between the probe card and the wafer.
After loading the probe card and wafer, the prober’s camera optically locates several probe card tips and pads on the wafer.
It then employs this information in the alignment of the device under test’s pad to the card’s contacts.
Can You Employ A Single Probe Card To Test Several DUTs In Parallel?
Yes, you can.
You can use a probe card to test several DUTs (device under test) when in parallel configuration. However, you still find wafer testing done on a single device at a time.
Using a probe card to test several DUTs in parallel simultaneously reduces the test time significantly compared to individual testing.
What Tests Can You Perform Using A Probe Card?
When using a probe card, you can perform three tests as follows:
- An AC test which allows you to highlight the circuit’s output signals’ waveform.
- A DC test which identifies shorts or opens alongside the circuit’s output current and voltage.
- A functional test is more elaborate and time consuming test that seeks to establish the chip’s functionality.
What Are The Some Of The Types Of Probe Cards?
The classification for probes is broad depending on various factors such as the shape of the contact elements.
Some of the available probe card types include:
Blade cards find use in applications with probe densities ranging from low to moderate and reduced point counts.
You can use blade cards in applications associated with high frequency and temperature and low leakage.
This probe types takes advantage of MEMS technology allowing you to test logic devices and microprocessors with great accuracy and reliability.
MEMS is an acronym for Micro Electro Mechanical System, and it is presently the most advanced probe technology in the market.
With just one contact movement, you link it to the wafer of the DUT.
The epoxy ring technology design suits applications requiring high probe density and point counts.
In some custom multi-DUT probe cards, you can find probe numbers of up to 2000.
Blade cards were once the most common technology for parametric testing due to their inexp ensiveness and adaptability for low-level measurements.
Epoxy cards currently find common use as their cost has decreased and their leakage performance enhanced.
The U-Probe is a probe card specifically designed for measuring memory devices.
It requires only one contact or to interact with a wafer up to 12 inches in diameter.
A U-probe card also delivers an even scrub for the best possible outcome.
It can also be utilized anywhere on the semiconductor wafer, in any position.
Vertical probe cards find use in the multi-die testing of devices such as general logic and microcomputers.
The needles are short and oriented vertically with respect to the substrate.
This makes them suitable for wafers with small pads and high frequency.
What Are The Advantages Of Employing Cantilever Probe Cards?
You find the following advantages of employing Cantilever probe cards:
- You can achieve fine pitch for as low as 25 micrometers.
- Cantilever probe cards can support multiple dies.
- These cards can tolerate high temperatures lowering thermal effect on the card and wafer.
- These cards can support high voltage and/or current input.
- Cantilever probe cards record very low leakage measurements.
- Using cantilever probe cards allows you to match impedance and reduce the length of the probe.
How Can You Classify Ceramic Blade Probe Cards?
Ceramic blade probes provide great mechanical stability as well as a signal route with high integrity. These cards rarely require re-planarization or alignment in typical use.
ceramic blade probe
The three most common types of ceramic blade probe cards are:
- Standard blade: These are common where controlled impedance is not essential.
- Microstrip blade: while useful for areas requiring controlled impedance, the signal path connects directly to a transmission line.
- Radial microstrip: These are especially useful where controlled impedance is necessary with direct board connection of the signal path.
What Are The Parameters Of A Ceramic Blade Probe Card That Influence Performance?
The parameters of a ceramic blade card can be tweaked to maximize the probe’s performance for a specific application or operating environment.
The blade thickness, and shank width and depth are the ceramic blade parameters with the most impact on performance.
You can increase the blade’s thickness to improve stability.
The number of probes in the array and their closeness to one another determines blade thickness.
You can increase or decrease the surface area where you join the blade to the by adjusting the blade’s shank width.
This has an impact on the wire probe’s flexibility and the contact force it applies to the wafer bond pads.
The shank depth is the blade’s third changeable parameter.
You can increase the distance between the probe card PCB and the wafer under test by increasing the shank depth.
What Are Some Of The Technical Requirements You Consider When Selecting A Probe Card?
When selecting a probe card, you consider the following technical requirements:
- DC related parameters such as contact resistance, current capacity, signal path resistance and leakage.
- AC related aspects including capacitance, rise times, bandwidth and crosstalk.
- Mechanical aspects such as contact force, layout, alignment, planarity and pad size and pitch.
- Environmental conditions such as temperature and humidity levels.
What Are Bond Pads In Probe Cards?
The metalized sections on an IC chip where the test probes make contact are known as bond pads.
You identify bond pads using their positional X, Y coordinates.
You can define the bond pad size as identical to the passivation opening size, or to the metallization size. The passivation layer overlaps the margins of the bond pad metallization.
Consequently, the useable area is frequently 10% smaller in both dimensions than the metallization.
The size, spacing, and layout of bond pads influences the design of epoxy and blade probe cards for wafer testing.
What Is The Difference Between Pad Size And Pad Pitch In Probe Cards?
Describing pad size involves mentioning the width and depth of the pad with regard to the passivation opening.
While the pads don’t have to be square, having great depth as opposed to width is preferable.
Pad pitch describes the distance between neighboring bond pad centers.
Where you have bond pads with unequal spacing, you describe pad pitch as the least spacing between pad centers.
What Materials Can You Employ In Making Probe Card PCBs?
While you can employ different materials in making probe cards, you find the use of FR-4 and polyimide material more common.
Between the two, FR-4 finds wide usage due to its relatively lower cost.
You find FR-4 material typically employed in probe cards where the probing temperature does not exceed 100 °C.
Alternatively, polyimide material finds use in probe cards used in probing processes where the temperature is in excess of 100 °C.
What Are The Some Of The Probe Card Design Guidelines?
The design guidelines of probe cards may vary with the fabrication process. However, some of the important guidelines are as follows:
- The metal to metal spacing in your probe cards should be at least 5 mils.
- Avoid locating metal features close to routed or non-plated via edges ensuring at least 0.05 inches of space.
- Ensure a low leakage design by carefully selecting the fabrication materials, their handling and probe card layout.
- When laying out the probe card, employ at least a millimeter for surface feature separations.
- Restrict signals sensitive to leakage to the outer layers while employing ground traces for such signals.
- Maintain the widths of the signal paths to achieve controlled impedance.
What Materials Do You Use For The Probe Card Needle?
You find the following materials employed for the probe card needle:
- Tungsten: Finds particular use when probing aluminium lands while providing long term use due to its hardness.
- Tungsten-rhenium: Contains 97% tungsten and 3% rhenium with similar properties to tungsten but with higher contact resistance.
- Beryllium-copper: Finds use in applications requiring high current values or low contact resistance.
Its softness however causes the needles to wear out quickly limiting its use to non-stringent applications.
- Paliney®7: This material includes palladium, gold, silver, platinum, zinc and copper making it expensive and harder compared to beryllium-copper.
You employ this unique material where you require good conductivity and low contact resistance.
What Factors Should You Consider When Choosing A Probe Card Needle?
You need to consider the following factors when choosing a probe needle:
- Its low frequency testing capability with regard to low and high current applications, isolation, power dissipation and series resistance.
- High frequency testing capacity considering inductance, crosstalk and probe impedance.
- The lifespan of the probe card needle subject to its wear, cleaning process and contact resistance.
What Is Probe Card Geometry?
When defining probe card geometry, you find highlighting the following different aspects necessary:
The die size determines the beam length in conventional probe card design.
You provide beam length in mils and it’s the horizontal measure from the probe tip’s centre to the probe’s termination point.
The bend angle defines the internal angle you achieve after bending the probe and is provided in degrees.
Probe Tip Depth
The depth of a probe tip describes the distance from the reference plane to the plane created by the tips.
The probe layer count, probe angle, tip and beam lengths, and ring thickness influence the probe tip depth.
Etch length is unit-less and defines the distance from the beginning of decreasing wire diameter to the probe’s tip.
The tip length is the distance from the probe’s tip to the point of bend provided in mils.
Probe Wire Diameter
Probe wire diameter influences pad pitch and contact force and is given in mils.
Generally, you have diameters between six and fifteen mils, however extreme diameters are cumbersome during processing and best avoided.
The tip diameter of the probe influences tip contact resistance and bond pad damage.
You can have a convex or concave etch though an isolinear etch is more popular.
You find the tip etch susceptible to wear resulting from abrasive cleaning increasing the diameter and reducing the tip length.
Probe Tip Shape
The probe tip shape affects the card’s contact resistance and the level of bond pad damage.
You can have a flat shape or semi-radius with the latter requiring extra processing upon sanding hence takes time to produce.
What Are The Parameters For A Probe Card?
You find the following parameters for a probe card:
Contact Resistance is the surface resistance between the tip of the probe and the bond pad.
You note that it is influenced by the pad and probe materials, tip diameter and shape, and the contact force.
The contact force of a probe is the force applied by the tip on the area of contact. You measure the force in grams and the length of the tip in mils or microns.
Overdrive describes the vertical movement upon the initial probe contacts.
The vertical distance between the highest and lowest tips on a probe card is known as planarity.
It specifies the vertical distance between where the first tip makes electrical contact to where the last tip makes contact.
Probe Alignment Accuracy
When using wafer bond pads, alignment accuracy describes the probe tip placement accuracy at overdrive with respect to the highlighted points.
In case of a probe card analyzer, alignment accuracy describes the scrub mark’s center position with to the bond pad’s.
The scrub mark describes the path of sliding of a probe tip. This is typically across the bond pad from the initial contact to where it rests at full overdrive.
Can You Use High-Temperature Testing For Probe Cards?
You define anything above 100°C as high temperature probing.
High temperature probing necessitates the employment of specialized materials and processes for hot chuck alignment.
Because of its unique alignment features, you cannot utilize a high temperature probe card for ambient testing.
While you employ extra manufacturing procedures in making high-temperature probe cards, the card’s alignment is highly unreliable.
Thus, you need to avoid high temperature probing where possible.
Why Should You Carry Out Cleaning Of Needles In Probe Cards?
One of the most important reasons for probe yield loss is contact resistance.
Contact resistance increases due to accumulation of contamination on the probe tips.
Presently, the greatest strategy to improve the probe tips’ long-term function is to include periodic cleaning processes.
Performing cleaning treatments on a regular basis can help to avoid yield loss caused by increased contact resistance.
You consider a variety of factors before deciding on a cleaning technique.
The two key criteria that affect the longevity of your probe card are probe wear and cleaning frequency.
What Causes Accumulation Of Dirt On Probe Cards?
When impurities build up on the probe tip, they interfere with the probe’s surface and electrical contact increasing the contact resistance. Common causes of dirt accumulation on probe cards are:
- Oxides of tungsten and aluminium.
- Packing materials out-gassing.
- Silicon nitride.
- Fluorocarbons and polymers.
- Buildup of dielectrics through electrical activation.
What Cleaning Methods Can You Employ On Probe Cards?
You need to carefully select your probe card cleaning methods.
When choosing a cleaning procedure, consider the probe material and tip shape, as well as their reaction to different cleaning methods.
Some of the cleaning methods you can employ include:
- Using a ceramic disk or tungsten carbide scrub
- Employing sticky paper on the touchdown points.
- Dry brushing using camel hair.
- Using a high frequency acoustic tank with a mixture of solvents.
- Wet brushing.
How Can You Improve Probing And Testability Of Probe Cards?
The following can assist you in improving the probing and testability of probe cards:
- To minimize bias oscillations, provide a DC ground return pad on either side of the DUT.
- You need to provide a reliable RF chip launch by having RF ground in close proximity to their respective signal pads.
- Inhibit RF degradation through lead inductance by tying the grounds together on the wafer.
- Where you have large probes, provide signal isolation and enough spacing by logically positioning the RF pad around the wafer border.
- Employ common probe use in any RF application via conventional RF pad signal footprint.
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