Zoom in defect of engineering microscopes

As early as the 17th century, scientist Anton van Leeuwenhoek, through a rough microscope microbiology, and since then has been the existence on the microscope higher performance needs.

As the Leeuwenhoek microscope on the influence of science, today's microscopy system also influenced the development and test Semiconductor Engineer components and materials, as well as micro electro mechanical systems (MEMS) technology.

Now, destructive and non-destructive microscopy tool is a scanning electron microscope (SEM), and even beyond the latter, a well-equipped laboratory's flagship device.

A new generation of instruments have reasonable pricing and user friendliness, is moving towards imaging and analysis work, such work was outsourced back into the manufacturing environment.

Measurement and observation

As semiconductor devices, optoelectronic devices and associated devices are from smaller overall dimensions and new materials (such as SiGe) benefit, on the microscope with more demand.

Measurement and observation skills to become very interesting.

Hyphenated Systems is a wafer fabrication applications microscope manufacturers, its Vice President and General Manager of Terence Lundy explained: "3D imaging is particularly important.

The combination of 3D and measurement to let people see and measure semiconductor characteristics of indicators, such as channel and Silicon vias (TSV), as well as the surface edge and roughness measurement, etc. ”

TSV founded in wafer manufacturing process or after the period of Assembly, and packaging.

TSV-Tablet core and provide interconnection between wafer stack, thereby eliminating the line pressure welding for high density, the small size of the device.

To enable the engineer can see TSV such nanotechnology, Hyphenated HS series of mixed NanoScale Optical Profilers will traditional white light optics technology and a patented method — advanced confocal microscopy (ACM).

ACM uses an open framework to support future improvements.

ACM can observe MEMS, ink, digital light processor and electrical test probe card for italic or rough surface, embedded transparent materials interface, as well as characteristics of high aspect ratio.

Software for imaging, measurement and automation capabilities provide a control interface. In addition, the measurement program can extract critical size.

If necessary, can also be combined with ACM Atomic microscopy (AFM), optical technologies and measurement methods, which not only meets the needs of imaging and measurement, but also to meet the analysis requirements.

Hyphenated system price range from approximately $ ~ $ 7.5.

Lundy, stacking multiple chip technology is the ACM's emerging applications.

He said: "IC company is seriously using 3D package and interconnect. Some chip designers even use hollow TSV. These channel pump into the air or gas is cooling the internal structure of a stack. ”

In the past, 3D microscope may need a interferometry, SEM and the combination of the AFM.

Unfortunately, a number of inherent defect prevents these technologies in a tiered application of chip packaging. For example, SEM needs destruction test devices (DUT) and Interferometry need sample DUT absolutely smooth.

Lundy said: "in 3D chip package, the perfect plane does not exist.

In fact, some surface is deliberately placed in some perspective. Detecting a depth other than the limited capacity and cannot see through various layers, this is in 3D chip observation with interference method of an obstacle. ”

Similarly, the AFM (actually touch the DUT samples) cannot intervene in the internal 3D structure.

Lundy said: "can be very good to see that the surface, but not its structure. ”

And they instead, confocal microscopy sample preparation is not required, nor will they be overturned or skew the DUT, can be used to penetrate glass transparent media.

The instrument will be Hyphenated ACM Systems analysis and out-of-business detection microscope Nikon white, can guarantee low to 5 nm in the z axis resolution. In addition, and those that produce ion or electron beam microscope, the company's instrument samples does not need to be placed in trouble vacuum chamber.

Lundy says: "the 5 nm resolution exceeds most IC manufacturers the most courageous dreams.

In the past using SEM or AFM of people can now use ACM, thus avoiding long preparations and destructive testing. ”

Use the Hyphenated ACM Systems microscope can leverage a Los completed measurement.

When the need for follow-up survey, movies on x-y can accurately reposition.

Detection probe marks

In addition to providing a 3D image of the IC, the latest micro tools also help engineers check wafer probe damage caused by, including a thin semiconductor materials and ultra-small spot of ultra-small pressure probes and card.

With the rapid growth of chip density, wafer probe need more contact. If you contact a pad of the PIN is not a total surface, the probe will drill into the surface materials, damaged pads or in other layers.

Although with a welded ball can pressure welding a corrupted pads, but over time, the downstream will probably fail.

Lundy said: "trauma chip might be in a few months after the failure, the ball will disengage from the pads on. In the final product, this would be disastrous. ”

Probe mark is also a problem.

Probe marks from the probe and pads of physical contact, this is the phaseWhen the common. But too many prints reduced yield and device reliability. And penetrating, large or deep or misplacement needle marks will give rise to adverse pressure welding line, especially in high density multi chip package.

Some of the pressure of layers and spot column when the detection and isolation materials, causing conductance of particulate pollution.

IC manufacturer hopes to be a wafer cut into chips used to see these potential pitfalls.

SEM and AFM is often used to check the penetrating and probe marks, however, this observation might take hours or even days.

This is to 7 x 24 production IC wafer Foundry is not the best solution. Lundy said: "the chip manufacturer wants is a closed-loop measurement method. People hope to millions of contacts for quick detection of trend analysis. "ACM will support this analysis.

Connection creation and destruction

In addition to a complete failure analysis and determine the device characteristics, some microscopes also provides ancillary concurrent development cycle.

For example, FEI's focused ion beam (FIB) product provides an interactive technology, for companies call V600 Circuit Edit.

V600 Circuit Edit can identify and fix component due to the interruption of electrical connections and the generation of nano-level problems.

In fact, it can generate function prototypes, enable manufacturers to complete product development and validation, to 65 nm following devices for mask correction.

FEI series of six FIB micro products now have a Circuit Edit properties.

The company's product marketing manager Peter Carleson explained that these products can provide a variety of resolutions. The Corporation of wafer Expida 1255S DualBean can be used for fault analysis, it is a combination of wafer level scanning transmission electron microscope/(STEM) sample preparation and high-resolution imaging and analysis of the FIB.

These technical instruments use focused ion in sample drilled, typical aperture approximately 10mm×10mm.

The tool uses an electron beam in the holes drilled into to probe deep have no short circuit or open circuit. From automatic test equipment (ATE) of test vectors can be fault location and venue.

Carleson explained: "you can use the ion beam to cut a section, while the observation by the electron beam to locate defects.

SEM also use shorter than visible light system bundle of wavelength, so the resolution is also higher. ”

Another benefits of improved depth of field.

Carleson pointed out: "optical microscope depth of field in the order of a few microns, SEM and ion beam depth of field is 10mm ~ 50mm. "When checking for MEMS devices, depth of field is critical at this point in the z-height on which there is a considerable changes. More technology you can see the entire sample to microscope, everything can be focused.

If you need higher resolution, ion-beam microscopy can sample slices.

Typically, a 50 nm thick slice is placed in a transmission electron microscope (TEM). TEM was like a slide projector, and then use the atomic-level resolution renders an image.

Finally, FEI's Expida 1255S wafer DualBean such instruments can also be used for electrical detection.

Carleson said: "this is a rapid development of applications. ”

　　

Compensate for the difference

FEI Phenom desktop microscope widened in microscopy applications, said it made up for the optical microscope, SEM space between.

And characterization for 3D Hyphenated and needle marks measuring, probes and through-hole of the ACM, Phenom is intended primarily for quality control applications.

Carleson said: "it is a back-end tools, you can give other microscopy sample preparation.

"Phenom with touch-screen operation, can provide the 10X ~ 20000X magnification (optical microscope about 20 times).

The product also comes with an optical camera for so-called "never lose" navigation, plus an electronic microscope.

Sample through a kind of automatic vacuum technology mounted, it surpasses the trouble of vacuum chamber. Does not require isolation mount external vibration, sample took less than 30s.

Phenom weight just over 120 pounds, also provides 120X digital zoom, with up to 2000 x 2000 pixel image resolution, image can be saved in the USB disk.

FEI Phenom is expected, and SEM similar performance will attract those who can't afford to pay more than $ 25 million to buy a SEM's Studio, not to mention the fact that there are training SEM operations staff and dedicated facilities costs.

One 7.2 $ Phenom microscope can be used to check the packaging defects, such as interconnection and whiskers.

Carleson said: "these types of failures are extremely small, but do not necessarily need SEM resolution and magnification to see them.

In many applications, a Phenom can complement the SEM. ”

　　

Manufacturing precision

At least a charged particle manufacturers are beyond SEM technology, turning to Helium Ion microscopy.

Carl Zeiss SMT Board of Directors, Managing Director Dr. Dirk Stenkamp said: "IC manufacturers now have a paradigmType of transfer. Microscope must follow. ”

Stenkamp said that material progress and more strict process control are driving around on manufacturing high-precision measurement needs.

"Now that the material is IC manufacturing key factors. ”

Complex of materials (such as SiGe, high-and low-k dielectric k, as well as for the interconnection of the type of metal) requires new tools.

SEM such traditional technology lost advantage here.

Stenkamp is the Orion microscope Zeiss is called a breakthrough.

The microscope starting at about $ 1 million, and now the United States National Institute of standards and technology (NIST).

Orion microscope using a helium ion beam generated signals instead of the electron beam.

These instruments can be observed in less than one Micron's characteristics, can be used for fault analysis, critical dimensions measurement, observation and identification of material defects.

Helium Ion Microscope can also improve spatial resolution.

SEM resolution in 1.5 nm and 2 nm, helium ion microscope 0.2 nm resolution, high about one order of magnitude. Stenkamp said: "this tool is a great way to make up for the SEM and TEM gap between. It also makes up for TEM 0.2 nm resolution state. ”

Stenkamp also pointed out that Helium Ion microscopy can use inverse scattering (back-scattered) Ion generation SEM can't get contrast characteristics.

"It can clearly see a sample of the different types of materials. Helium Ion microscopy SEM can provide more than an order of magnitude higher about depth of field. ”

Analysis of nano-level samples

Thermal field launched (FE) electron probe micro Analyzer (EPMA) go further.

JEOL USA by EPMA to SEM and x-ray analysis. JEOL's JXA-8500F models to price of $ 1 million, with a lens-type (in-lens) Schottky FE provides high probe current electron gun. It produces a probe diameter is the traditional one-tenth of the probe. And the Orion microscope Zeiss, JEOL products now being examined by NIST for failure analysis and quality control application to track test, not only for R & D.

EPMA wavelength-dispersive x-ray Spectrometer (WDS) can be completed from 40X ~ 300000X image magnification.

In addition, it also does not require ultra-high vacuum chamber.

JEOL Vice President and product manager Charlie Nielsen explains: "with the size of the zoom, you must reduce the penetration of electron beam, which is a low voltage system provides useful.

"He pointed out that the high voltage of previous generations of microscope is typically required sample size in a cubic micron level, but can be used only by EPMA 100 nm size samples.

JEOL's non-destructive microscope can simultaneously deploy a spectrometer and up to five WDS.

Nielsen says: "committed to nano-technology vendors (such as MEMS materials and hard liner films) can use this technique for microscopy out R & D lab and into the field of quality control. ”