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Semiconductor Failure Analysis

Sample preparation by cleaving is used in semiconductor failure analysis and quality control laboratories. The key applications include*:

  • Preparation of cross sections for analysis by scanning electron microscopy (SEM).
  • Downsizing of full wafers and pieces for electrical probing, surface analysis or further processing.

The cleaving methodology depends on a number of factors including:

  • Will the final sample be viewed in the SEM and does the SEM have sample height limitations?
  • What target accuracy and repeatability is required.
  • Substrate thickness, thickness and materials on the surface.
  • Crystal structure of the substrate ((100), (111))
  • Orientation of the lithography relative to the substrate (rotated lithography on (100) silicon)

*A good reference document for semiconductor applications is found in the Microelectronics Failure Analysis Desk reference, Seventh Edition. Tejinder Gandhi, editor DOI:10.31399/asm.tb.mfadr7.t91110402

Cleave Copper Bumps for SEM Analysis
Copper C4 Bumps cleaved with the LatticeAx CLICK to Read More
Use of the FlipScribe to downsize to 1mm wide samples
Using the FlipScribe to make 1 mm wide samples CLICK to read more

Preparation of samples for SEM

On the right is a 4x3mm sample. It was downsized from 10x10mm in preparation to be viewed in a SEM with sample height restrictions. This is common requirement for SEMs with immersion lenses. CLICK to see the applications note and movie. The movie shows the downsizing process which keeps the SEM area of interest clean.

On the far right is a SEM image of a memory structure directly after cleaving. Note that backend structures containing metal will commonly need to be "polished" with an ion mill before fine structures can be resolved in the SEM. Go to the publications section and download the paper "From Transistors to Bumps..."

SEM image of memory structure after cleaving
Image of a memory structure directly after cleaving.

Downsizing samples for analysis or processing

In addition to downsizing wafers to die sized pieces, the LatticeAx is used for thin, small and even off crystal axis cleaving. The image on the right shows the diamond wedge indenter of the LatticeAx precisely positioned on the sample to control the location of the cleave. As the indenter is lowered it creates a defect on the sample surface that eventually causes a cleave to propagate. This method is called "indent to cleave" and can be used on silicon, GaAs and other crystalline, thin samples. Read more about this application HERE

On the far right is an image of a (100) silicon sample cleaved using the FlipScribe. The FlipScribe scribes the sample with a diamond scribe on its backside. This means the scribe never touches the fragile features on the front side. If your samples is large >1"/25mm it best practice to downsize the sample with the FlexScribe and then perform the final downsizing with the FlipScribe. 

 

Solutions

The solution may require one or more tools to get the job done. For instance:

Don't see your application here, CONTACT US for a recommendation.

Products for Semiconductor Applications

Based on your application LatticeGear can recommend the right tool set. Please contact us!

 

 

Cleaving Tools

There are a number of accessories that will be important for your laboratory. 

CleanBreak Pliers with 3 Sets of Jaws. After scribing you will need to cleave your sample. It is possible to cleave over a sharp edge but the pliers provide symmetrical force when cleaving the sample. Cleanbreak pliers are used for samples 20mm/.75" and larger.

Small sample cleaving pliers. For samples <20mm/.75" small sample cleaving pliers are required. They will work well for samples up to 1mm thick. For thicker samples cleave with the Small sample cleaver.
The Small sample cleaver cleaves samples that are small <10mm wide and cannot be handled with your hands or tweezers.
Can't decide what you need? A good starting point for every lab is a cleaving kit. The cleaving mat keeps the workspace organized and easy to clean.

 

Videos

Watch videos showing the operation of the scribing and cleaving tools and systems.

 

FlexScribe For Wafer Downsizing
Operating the LatticeAx 120
Operating the FlipScribe
Making small samples for SEM

 

Using the small sample cleaver
Cleaving with Cleanbreak pliers
Cleaving die from a (111) Silicon wafer
Using the FlipScribe to scribe and cleave at 45 degrees

 

Semiconductor Publications

Publications (for copies, contact lg@latticegear.com) or for downloadable copies of these publications you must be registered and signed in

Download
QuantTera, GaAs Wafer Cleaving
Download
Cleanroom Technology, Clean Cleaving
Download
Global Foundries, A Controlled Mechanical Method for MEMS Decapsulation (poster)
Download
University of Copenhagen, Successful Cleaving of Delicate Nanostructures
Download
ISTFA 2014, Conference Proceedings Advances in FIB-SEM Analysis of TSV and Solder Bumps - Approaching Higher Precision, Throughput and Comprehensiveness
Download
Solid State Technology, From Transistors to Bumps: Preparing SEM Cross-Sections by Combining Site-specific Cleaving and Broad Ion Beam Milling
Download
EDFA Journal, Cleaving Breakthrough: A New Method Removes Old Limitations

 

scribers and cleavers

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