Laser Resizing Silicon Wafers, Substrates, and Laser Machining Silicon Devices such as Sensors, Detectors, and Solar Cells

Laserod specializes in laser processing of silicon such as resizing by downsizing Si wafers and laser machining Si devices such as sensors, solar cells and other photovoltaic devices as shown below.

Resizing silicon wafers (downsizing) by precision YAG laser cutting

Silicon Wafer Resizing

by Laser Cutting

A common resizing is downsizing 12" to 8" as shown here. Other common downsizings include: 8" to 6"; 6" to 4"; 12", 8", 6" or 4" down to multiple 2" wafers. Practically any kind of downsizing by laser cutting is possible. Ask us.

Wafer Resizing Services: Downsizing, grinding/polishing, laser marking, dicing, flat or notch, thinning by grinding/polishing, and backside scribing.

Very large laser trepanned hole cut in silicon. Can be a resized Si wafer.

Very Large Trepanned "Hole" or smaller resized wafer, whatever.

Circular cuts in silicon wafers.
3mm (.125") dia. Thickness is 175mm (.007").

Laser drilled percussion holes in silicon wafer.

Array of Laser Drilled Percussion Holes in a Silicon Substrate

in 625um thickness Si

Overall 12mm dia

Small hole dia 0.125mm (125um)

Laser drilled trepanned hole in silicon.

Profile of Laser Trepanned Hole Drilled in Silicon

0.700mm dia.
Laser entrance side, cleaned mechanically. Thickness is 0.5mm (.020").

For more on laser hole drilling click here.

Trepanned Holes in Silicon

0.125mm (.005") dia.

Debris is from a Styrofoam cup used to gently but effectively clean off laser debris. Nice mechanical cleaning trick, huh? Thickness 0.5mm. Note the laser scribe at lower left.

Laser Cutting a Silicon Edge at an Angle

Fancy laser cutting at a 45 degree angle.

Guidelines on Si Processing by Q-switched YAG Laser

These first 3 pertain to holes, cuts or scribes:

Max Depth: 1mm
Min Depth: none
Typical Depth of Penetration: 0.5mm

These next 6 pertain to drilling holes only:

Max Dia of Trepanned Hole: none
Min Dia of Trepanned Hole: 50 microns
Max Dia of Percussion Hole: 50 microns (up to 25 mil thickness Si)
Min Dia of Percussion Hole: 15 microns
Taper of Trepanned Hole: (ask us)
Taper of Percussion Hole: (ask us)

The next 2 pertain to cutting or scribing.

Kerf Loss: Width of cut for 0.5 mm thick Si (full penetration cut) is 50 microns at top and 25 microns at bottom of cut.
Edge taper is best evaluated on samples we create for you.

These last 2 pertain to all: drilling, cutting and scribing.

Laser Debris: entrance side only, none on laser exit side. Debris field is an easily removable haze. If desired, remove with Q-tip, Styrofoam,fi DI water, ultrasonic cleaning, etc. For MEMS devices we use special techniques.

Laser processing of silicon naturallly creates a hazy residue of redeposited silicon particles, again on only one side.

We have two basic methods of working silicon without contamination (others for MEMS):

Method #1: Back side drilling, cutting and scribing of silicon

Backside work requires registration to the front side which is achieved by the use of custom optical registration providing precise location.

Method #2: Front side drilling, cutting and scribing of silicon

Registration is through the laser focusing lens, allowing us to see with the same magnification as the laser sees. Fiducials work great for alignment. We align to +/- 5 to 10 microns typically. We can increase the laser magnification and improve this, if required.

Contamination control techniques include the use of photoresist or equivalent coatings. There are no post laser marks left on the silicon after cleaning off the coating. The coating must be removed, posing a problem for some devices.

Other contamination controls are the use of low power laser processing to minimize particulates and the use of vacuum exhaust. We can process parts in a full clean room.

Five Applications of Laser Machining in Silicon

Application # 1: Wafer Scribing & Resizing

Laser scribes are performed around the wafer to trim it to a specific size. An example is wafer resizing to reduce a large wafer to a smaller size. This is actually cutting, not scribing. Wafer scribing for "scribe and break" is typically to a depth of one third the wafer thickness. If the penetration is completely through the wafer, it is called "cutting" as contrasted to "scribing" which is a groove to a specified depth. We perform precision resizing and can "round" laser resized silicon wafers for your automatic handling equipment.

Application # 2: Via Drilling

Allows front to back surface contacts. Small percussion holes and trepanned larger diameter holes are both done.

Application # 3: MEMS

Micro-electromechanical systems devices (MEMS) are laser machined to provide channels, pockets and through features (holes) with laser spot sizes down to 10um and positioning resolution of 2-5um. Channels and pockets allow the device to flex. Our backside processing techniques are particularly applicable.

Application # 4: Wafer Flats

Additional Wafer Flats to aid downstream wafer processing. By adding another flat to the wafer, it is possible to handle the wafer with greater ease during the production process.

Application # 5: Metal Contact Isolation

Involves laser cutting for electrical isolation. Depths of the cuts can be to 5-6 mils and widths down to 0.5 mil.

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Whatever your requirements for silicon processing are, we are pleased to discuss it with you. Please call, e-mail or fax.