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Ceramic Scribing and Machining • LaTITE™ • Plug-Free Vias • Processing Ceramics Guide
The guidelines in this document represents the most effective design approaches for conventional applications. If your application needs can't entirely comply with Laseage specifications in this guide, we can offer viable alternative and can also help you solve unusual or special problems.
 Field-proven techniques and standards are offered to achieve the best substrate design for a given material and/or application. When the opportunity arises, we routinely suggest improvements and techniques to improve the products and reduce costs.
Lasered ceramic substrates used for batch fabrication of microelectronic circuits require specialized positioning and cutting accuracy. Under computer control, a laser can produce a broad range of features while maintaining tight tolerances.
Figure 1 identifies some basic substrate features in a ceramic substrate array.
The following are common substrate materials available from Laserage:
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| ADS-96R |
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A-476 |
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Rabalit 708s |
| ADOS-90R (opaque) |
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A-473 |
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| ADS-995 |
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| ADS-996 (Superstrate) |
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An economical, proprietary, heat treatment developed by Laserage scientists to enhance metallization adhesion to laser machined sidewalls of holes and edges. Particularly applicable to low or no frit inks, adhesion tests have confirmed pull strengths comparable to, or better than, as fired alumina. LaTITE™ treatment eliminates any reservation hybrid design engineers may have in using laser machined substrates for either high reliability applications or reaping the cost efficiencies of multiple part laser machined arrays.
A natural by-product of laser machining is the ultra thin, but fragile, "columnar layer" on hole walls in ceramic. The process securely fuses or bonds the fragile "columnar layer" to the hole wall. Typically the process is used for reactive (oxide) bonded ink systems substrates to dramatically improve metalization adhesion and thermal cycling performance.
The picture below shows a laser drilled hole wall in a ceramic substrate at high magnification. On the right is a laser drilled hole wall in a ceramic substrate with the LaTITE™ process. It's properties have been restored to those of a raw ceramic substrate.
Click on titles for detailed information and examples.
1 - Edge Treatments
For applications where edge surface roughness or straightness in the singulated part are important design considerations, additional steps may be required.
2 - Lasered Scribe Lines
A scribe line consists of a series of small, closely spaced "blind" holes lasered into the substrate under precise computer control. The hole or pulse depth is generally 40% ot the substrate thickness.
3 - Lasered Machining & Drilling
Laser machining and drilling offers effective alternatives to mechanical methods.
4 - Tolerances
Click to view established tolerances for various hole and feature characteristics.
5 - Raw Material Specifications
Click to view Table 4.
Quality is the responsibility of everyone at Laserage. We are an ISO 9001:2008 registered world-class manufacturer and supplier of laser services. Our certificate number is L112006 for "the precision laser processing of materials for all industries and the manufacturing of complex cable assemblies."
Laserage utilizes calibrated video inspections (up to 270x), optical comparitors (50x), microscopes (30x) and calipers for all measurements. Except where specified, all measurements are from the exit side of feature. If you require a mechanical pin fit, please specify your needs as "go" and "no-go" pin gauge requirements.
Pin Flats - All measurements are referenced from the center of the flat by focusing the video inspection system or optical comparitor to the farthest edge from the part. This point signifies the point of contact on your pin fixture.
Size and Location - Measurements are made using an optical comparitor or video inspection system with an x, y table and a minimum 4-place digital readout.
- Array - The finished part (as delivered to customer), which may contain one or more cells. (See figure 1)
- As-Fired Edge - The edge of a substrate produced by mechanical punching of unfired (green/raw) ceramic tape.
- Camber - Measured flatness or deflection of the ceramic substrate surface. Measured in thousands of an inch per inch of linear travel, measurements are accumulative. (See table 4)
- Castellation Hole - A laser machined hole located on a scribe line.
- Cell (Circuit) - One unit or section of a multi-up array. (See figure 1)
- Cusp (Bump/Tab) - Ceramic material left inside a laser cut feature at the result of the start/stop point of the laser beam.
- Datum - Reference point (0,0) from which all other features on the substrate are measured. (See figure 1)
- Feature - Any scribe, hole, reference mark or other cutting as specified.
- Feature-To-Feature Distance (web) her distance separating a hole from another hole or substrate feature, such as a cut-out. This distance is measured from the hole entrance side. (See illustration B)
- Fiducial - A marking used as a standard reference for substrate orientation and alignment during metallization. (See figure 1)
- HAZ - Acronym for Heat Affect Zone. Region of material adjacent to a laser scribe or cut, affected by the heat of the laser.
- LaCoat - Used to protect substrate surface during laser processing.
- LaTITE™ - Proprietary system of annealing ceramic for improved metallization adhesion and stress reduction. (See LaTITE™)
- Machined Hole (Contoured/ Profiled/ Via) - A laser-cut feature produced by moving substrate in relation to a fixed beam position.
- Machined Slot - cut or profiled feature produced by moving the substrate in relation to a fixed beam position, with length greater then width. (See figure 1)
- Machining/ Profiling/ Cutting - Producing a desired shape, such as slots or contours by cutting though a ceramic substrate with a laser beam.
- Microcracks - small fractures that may occur due to thermal stress. Typically caused by faulty part design, excessive laser energy, or mishandling.
- Pin Flat (Flat/ Pin Locations/ Alignment Flats) - Laser-machined reference plane, located on substrate edges used for precise mechanical alignment of the substrate in the customers process. (See figure 1)
- Popped Hole (Drilled/ Flashed/ Pulsed/ Via) - Pulsed or trepanned hole, laser-machined thru-hole processed by pulsing or rotationing the beam while the substrate is stationary. (See figure 1)
- Reference Notch (Chamber Corner) - Customer-specified feature used to define substrate or orientation during processing. (See figure 1)
- Scribe Depth (Pulse Depth) - Average penetration distance of a laser pulse, measured from the entrance side of the substrate. (See figure 4)
- Scribe Line (Snap Line/ Pulse Line) - A controlled series of pulse at a specified depth and spacing, witch allows separation into circuit segments. (See figure 4)
- Scribe Spacing (pulse Spacing/ Pitch) - Separation distance between two adjustment lasers pulses, measured from centerline to centerline. (See figure 4)
- Slag - Re-solidified ceramic matierl on the substrates surface, resulting from laser processing.
- Taper - Slope of the wall resulting from laser drilling or machining through the substrate thickness. (See illustration D)
- Tooling Hole (Reference/ Locating Hole) - Customer-specified optical and/or mechanical feature. Used to locate or fixture the substrate during metallization, assembly, or further processing. If using mechanical pin alignment, specify hole size using a go/no-go pin test. (See figure 1)
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