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Semefab (Scotland) Ltd
Situated on the East coast of Scotland and established in 1986, Semefab is an Industry-led, market-facing organisation which has a long and successful track record of developing and supplying siliconbased semiconductor processing technologies and products to the open market. The company started with the design, development and manufacture of ASICs and Opto ASICs in various, well-established technologies and has recently evoloved into the leading supplier of MEMS foundry processing. The company is ISO9001-2000 and ISO14001 approved.
Full custom CMOS and Linear IC design is available as a sevice as is the preparation of CAD files for mask making. Process engineering and process development staff with extensive experience in IC processes and thin film MEMS are available to advise and assist customers on process architecture, customisation and characterisation. Comprehensive electrical-testing facilities, with diagnostic capability at extremes of temperature are available.
Specialised expertise exists in optical filtering on chip and in provision of optical stimulation during electrical testing. Semefab developed the world?s first fully integrated optical smoke detector ASIC. Other applications for ASICs produced at Semefab are in PIR detectors, roadside hazard warning light controllers, remote garage door opening, power supply monitors and motor controllers. A range of discrete components such as JFETs, Bi-Polar transistors, PIN diodes, RF transistors and MOSFETs are also manufactured. Five years ago, Semefab?s first MEMS customer requested a foundry service for processing silicon for application in pressure sensors.
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Since then the MEMS business has grown and now accounts for over 35% of turnover. Semefab currently provides a 100mm silicon foundry service for MEMS products based on thin film membrane technology for devices such as Thermopiles, Pressure sensors and Gas sensors. These devices can be found in many applications ranging from commercial and domestic through to automotive. Deep Reactive Ion etching [DRIE] using the Alcatel-Bosch I-Speeder technology for anisotropic etching and bulk silicon removal of high aspect ratio structures is available now.
One stop shopping is a common expression used in many industries and this is certainly the service that Semefab has to offer. Customers can approach Semefab for the design, development through to production of Semiconductor and MEMS devices in a variety of fields
It has long been recognised that the support of the MEMS industry requires CMOS-incompatible processing, which is fundamentally detrimental to CMOS devices. It is with these constraints in mind that Semefab has spent the last 7 months installing a new clean room with completely separate facilities to cater for processes which are potentially contaminating to CMOS and Linear IC manufacturing. This new clean room is now on stream and operational adding a broad range of new processing capabilities for a wide variety of applications.
Developments are underway for supplying potential customers with foundry processing for new and exciting applications for example in the monitoring of CO2 for automotive applications, RF MEMS switches based on cantilever type devices, MEMS microphone applications and MEMS gyroscopes.
Collaboration with university institutes, research laboratories and industry are providing Semefab with a plethora of new opportunities to further diversify the technology capabilities of the company.
Semefab is actively pursuing further collaboration and joint venture agreements with companies on a global basis. It is the aim of the company to become the natural partner of choice for the development and production of new MEMS products
SUMMARY OF PROCESSESS AVAILABLE
Front End 1 (CMOS Compatible):
Laser scribe
Diffusion:
Oxidation/Diffusion to 1250°C
Boron doping, BN disc, gaseous (BBr3)
Phosphorous doping, POCl3, PCl3
Chemical Vapour Deposition:
Low temperature oxide (LTO), 430°C, Ph doped, undoped, Tox: 100nm to 2500nm LPCVD nitride (800°C), Tnit: 10nm to 400nm LPCVD polysilicon 530 to 63°C, 100nm to 1,000nm PECVD nitride, oxynitride, oxide, 370 to 430°C, 100nm to 1,000nm STS Multiplex nitride, oxide, oxynitride, 200°C, 100nm to 1000nm
Metallisation:
Aluminium (Al, Al1%Cu, Al1%Si) Sputter 50nm to 5000nm Aluminium Evaporation, 50nm - 5µm
Implant: B11, P31, As 25 ? 150KeV to Tdose 1e16.
Photolithography:
Projection Photo (PE300, 500, 550, 600) minimum feature size 2µm, alignment tolerance +/-1µm with autoalign Double-sided align/photo (KS150) Resist coat (SVG), positive resists HPR504, OCG 825-35CS, ASPR 5503, 1µm to 4µm Double-sided resist coat (EVG150)
Etch:
Plasma oxide, nitride etch (Tegal 903), C2F6, CFH3 Plasma silicon, nitride etch (Tegal 901, Tegal 701) SF6, O2, 1µ to 5µm Plasma metal etch (A360 Plasmatherm), BCl3
Wet bench:
Wet oxide etch, 7:1 BOE with surfactant, 15:1 BOE Metal etch, HUNT 16:1:1:2 premixed Alum etch
Pirhana (Sulphuric Peroxide Mix) and 2% HF Nanostrip Fuming nitric resist strip Silicon etch (HNA) Wafer grind MPS200, to 300µm minimum thickness
Front end 2 (CMOS Incompatible):
This facility became operational in June 2005.
Projection photo, minimum feature size 2µm Resist coat, develop (SVG), positive resists Lift off resist process for thin film patterning Plasma resist strip, descum (T915)
Metallisation:
Gold, Titanium, Nickel, Platinum, Chromium evaporation, 100nm to 2000nm Tin Paladium (Sn1.2%Pd) sputter Copper plate to 10µm+ using TiW/Au seed layer Alloy 300 to 500°C, forming gas, dry N2
Etch:
Ti/W plasma etch (T701) KOH silicon etch up to 600µm (using oxide/ nitride hard mask) Lift off resist strip Polyimide, and BCB dielectric films
Metrology:
Nanoline Critical Dimension measurement system Nanospec thin film thickness SEM Dektak surface profilometer M gauge resistivity measurement Surfscan particle mapping CMT wafer bow (film stress) measurement
Test:
Reedholm RI20 parametric measurement Testec high voltage (to 2kV), high current test system
New equipment set planned 100/150mm:
2 x 0.5 micron i line stepper
Double sided proximity aligner
EVG 150 Resist Processing C
EVG 150 Resist Processing D
Ultra thick SU-8 Photolithography
Polyimide Coat (photo)
Polyimide Coat (non photo)
KOH Bench
Oxide Etch Bench
Oxide Etch Deglaze bench
Metal Etch Bench
Fuming Nitric Bench Resist Strip
Overlay Bench
DRIE
ICP
Plasma Poly/Nitride Etch
Plasma metal Etch
Silicon/Polyimide/Resist Release
PCVD Oxide, Nitride, TEOS
CD Sem
3 x Furnace Stack
Wafer-Wafer Bonder
Spray Acid Tool
Resist strip
Spin Rinse Dryer
Critical Point Dryer
Ellipsometer
Pattern inspection system
In line particle monitor
Resistance Mapping System
Lightfield/darkfield scope
Thin Film Stress
Infrared microscope (voids etc.)
Existing Semefab intellectual property:
Custom ASIC ? Silicon gate
PPS 401 CMOS 3µm, 3-15v
PPS 403 CMOS, 3µm
Photodiodes
PPS 406 CMOS, 3µm, double poly
Custom ASIC ? Metal gate
PPS 201 CMOS, 7.5µm, 5-20v
PPS 207 CMOS, 7.5µm, 5-20v (photodiodes, light shield)
PPS 602 PMOS, 7.5µm, 50-20v (depletion transistors)
Custom ASIC ? Linear Bipolar
PS 151 Junction isolated, 8µm, 40v, 5A
Foundry Processes
PPS 301 RF MOS transistor
PPS 541 Gas sensor base
PPS 551 Pressure sensor base
PPS 561 JFET
PPS 582 Fast recovery diode
PPS 901 Oxide isolated HV-BI-CMOS