Applied Laser Technology Embedded Passive Trimming

ALT provides job shop services, including: –Laser trimming (resistor and/or capacitor) for: Hybrids Thick and thin film substrates Marking Embedded passives –A variety of laser wavelengths for: Micromachining Sciving Cleaning Scribing Drilling Outsourcing “Process Development Lab” Who We Are

Materials Processed (A partial list) Alumina Beryllium BeO AlN Transfer Tape Glass Quartz Fused Silica Sapphire Silicone Variations of Rubber Vinyl Teflon Polyimide Duroid Kapton Adhesives Parylene Polyurethane Mylar Nylon Epoxy Preforms Plastics Polycarbonates FR-4 G-10 Ferrite Silicon Stainless Steel Cold Rolled Steel Soft Steel Kovar Aluminum Brass Copper Gold Nickel Silver Lithium Niobate Germanium Resistors Capacitors

Laser Wavelengths For Processing 100 nm Excimer Nd:YAG CO2 Laser Type Wavelength 248 nm 1064 nm VISIBLEINFRARED ULTRAVIOLET 1000 nm10,000 nm 400 nm750 nm 10,600 nm

Resistor Trimming Thick film resistors Thin film on ceramic Embedded resistors Capacitors High-Volume Systems –Galvo Marking/Serialization Tie Bar Removal Large format Capability –Up to 24” X 30”

Embedded Passive Trimming Current Capability ESI Model 4700 Galvo based –4” X 4” field Servo driven S&R –24” X 30” travel

ALT Modifications Reducing Laser Spot Size –Now ~40um –Soon ~25um Added New Probing Capability –Reduces NRE Costs Added Software Tools for data transfer

Probe and Trim Guidelines Board and panel layout A systematic regular x-y layout of multi-up boards on a panel is preferred. This optimizes a fixed probe card solution. Pad placement A systematic, regular x-y layout of test pads is preferred. Test pads should be arranged in generally repeated patterns Both optimize “flying probe” approach. Test pads should be proximal to the resistors Probe access (horizontal or vertical) to the test pads should not hinder laser view or access (overhead, vertical) to any resistors of trim interest Pad size Robust test probes for this application have typical tip diameters of ~ 0.015” (150~375 μm) Resistors less than approximately 200  may require “4 point probing” (full Kelvin) for ± 1% tolerance testing Minimum pad size should be 0.025” (625 μm) diameter to accommodate typical test probes Pad sizes greater than 0.050” (1.25 mm) diameter significantly improve test probe placement accuracy

Probe and Trim Guidelines Resistor size The laser spot is approximately (35-40 μm) diameter depending on the subject materials. We will reduce to ~25 μm with new optics. High accuracy trims (tolerance  0.5%) are best obtained for resistors larger than x in 2 (500 x 500 μm 2 ) Resistors as small as x in 2 (250 x 250 μm 2 ) are trimmable, with tolerances dependent on material and resistance values. We have trimmed resistors down to.006 width. Resistor characteristics Resistor elements are subject to thermal effects during laser trimming Resistor elements are subject to electrical current and potential during test and trim Thermal coefficients of resistance may significantly reduce throughput performance and final process tolerances Power and potential coefficients of resistance may significantly reduce throughput performance and final process tolerances

Probe and Trim Guidelines Data File Preference DXF and/or DWG format files are preferred. A well done CAD file can serve as a "virtual part", allowing much of the planning and programming to proceed before actual parts are available. CAD files are inherently (though not completely) unambiguous in terms of interpretation. Physical location and size data tends to be inherently present. Non-geometrical data like resistor numbers, values, tolerances and annotation can be associated and included fairly easily. Lastly, we have developed fairly good (though still evolving) methods for translating CAD data into operational trim programs. There is always a lot of variability based on diverse creators of these files, but the CAD environment tends to constrain input to the essential physical parameters of the part.

Probe and Trim Guidelines Data File Preference We have also received data in a Spreadsheet format. However, there is a lot of flexibility/variability in both the type of data content that can be entered and in the layout of said data. This can make for a lot of work parsing and interpreting the file. For example, sometimes geometry (physical location) data is not present and/or extraneous statistical data is included unnecessarily (i.e. too much, too little, or superfluous information). We can and do make use of such files, but it generally involves more effort. Spreadsheets are great tools for computation and analysis, but not so good for translating part data to a functioning trim program.

Probe and Trim Guidelines Data File Preference Formats we do not like include the following: Gerber Excellon Drill "Plot" formats in general Anything Raster (bitmaps, TIFFs, PDFs, a crummy FAX etc.) Anything proprietary Chiseled stone tablets

To our knowledge, ESI no longer offers the M4700 for sale. We do get good support, but product knowledge seems limited to a few individuals. GSI? Hitachi? Equipment Status

Job shop service is our business. We specialize in quick-turn / prototype / process development We know laser trimming better than most. Open to expanding capability if need is there. ALT Future Plans

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