Facilities

UHV Sputter Deposition System

The ATC 1800 sputtering system is from AJA International. The system has three independently controlled 2-inch dc magnetron guns with capability of +/- 45^o in-situ tilt. An RF biasing source for cleaning substrates prior to deposition is also included. The substrate holder can accommodate 4-inch wafer and can be rotated during deposition. The system has a load-lock chamber including magnetic transfer tool. A radiant heating component using quartz halogen lamps has been incorporated in the system to allow for backside heating of substrates during the deposition and for heat treatment of as-deposited films. The temperature is monitored and controlled through a PID temperature controller.

A KSA Multi-beam optical sensor (MOS) was integrated to the sputter system enabling in situ, real time monitoring of thin film strain or stress. The measurement is based on substrate curvature measurement technique. It performs simultaneous detection of the laser spot array, which makes the measurement insensitive to the environmental vibration. The system has been incorporated in the sputter system with external triggering from rotation of the substrate, so it can measure stress evolution in the film during the deposition or post-deposition heat treatment.

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Vacuum Furnace System with Integrated Probe Card

The vacuum furnace system is currently configured for combinatorial thermal analysis of high temperature materials. It also facilitates a large variety of standard and novel materials testing by featuring repeatable and accurate thermal processes under numerous atmospheric conditions.

The furnace system is a top loading laboratory furnace integrated with a turbo pumping system and inert processing gas, which allow an operating pressure from < 10-7 Torr to 2 psig under inert gas atmosphere. The operating temperature ranges from ambient temperature to 1500°C, and the temperature uniformity is +/-10ºC at above 800ºC. During heating, the temperature ramp rate is up to 30ºC/min from ambient temperature to 800ºC, and up to 50ºC/min from 800ºC to 1500ºC. The hot zone of the furnace consists of a molybdenum mesh heating element, a molybdenum sample support plate, and multiple layers of molybdenum shields for thermal insulation.  The usable working area as defined by the hot zone and with specified temperature uniformity is 6” x 6” x 1” (~ 150mm x 150mm x 25 mm). The weight of the sample is limited to a maximum of 2kg. The furnace system is also equipped with safety features, which include automatic power shut-off in the event of cooling water interruption or over-heating in the hot zone beyond a set-point.

As part of the PnDSC system, the high temperature probe card is a special device to be incorporated into the vacuum furnace to test the PnDSC substrate at elevated temperature. It allows the substrate to be mounted inside and contains an array of probes to form contact with the electrode pads on the substrate. Electrical test signals are carried to the electrode pads through the probes, which are connected to the electrical feedthrough inside the vacuum furnace using high temperature ribbon cables. The current probe card has an operating temperature up to 250°C. A higher operating temperature probe card (up to 1500°C) is currently under development.

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Nanoindenter II System

The nanoindenter II system is a nanomechanical test system, capable of quantitative measurement of the mechanical properties of thin films and materials of small volume with great accuracy. Key features include:

• Quasistatic indentation with optional continuous stiffness measurement (CMS) mode
• Maximum load/depth range: 200mN, 100micron
• Load/depth resolution: 75nN, 0.04nm (in the most sensitive range)

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DMA System

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Tensile Tester

The Instron 8501 system is intended for tensile, compressive and fatigue tests. Key features include:

• Available load cell: 500N
• Digital interface
• A variety of fixtures are available for tests in other geometry.

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Bulge Test System

The bulge test is a technique for measuring the mechanical behavior of freestanding thin films. Silicon micromachining techniques are used to fabricate thin membranes out of the film of interest. The membrane to be tested is clamped mechanically onto a sample holder and pressure is applied by pumping a fluid into the cavity under the film. The deflection of the film is measured by means of a laser interferometer with a He-Ne laser light source. The interference fringe pattern is detected with a photosensitive resistor and the fringe intensity is recorded into the computer. The displacement resolution is half the wavelength of the light, i.e., 0.3165 mm. The pressure is measured with a pressure gauge with a resolution of 0.1 kPa. A maximum pressure of 200 kPa can be applied. The experiment is controlled by computer via a LabView data acquisition system.

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Mechanical Test System For In-Situ Adhesion Measurements

This high stiffness adhesion test system uses a four-point bend technique with specially designed sample, which enables the study of interfacial cracking behavior in multilayered structures. The system has a displacement resolution of 10 nm, controlled by a precise step motor, and a load resolution of 0.01 N. An environmental cell has been integrated with the system, which enables in-situ adhesion measurements in an ambient with controlled humidity and temperature or in aqueous environments with controlled pH.

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Anisotropic Etching Set-Up

This etch set-up is used for the anisotropic etching of silicon wafers. A special wafer holder is used to expose only one side of the wafer to the etchant, while maintaining the same pressure on both sides of the wafer. The temperature of the etch solution is maintained using a water bath; the concentration of the solution is kept constant using a condenser.

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m-BOSS Multi-Beam Optical Sensor System Using Diffraction Heads

The apparatus tracks the behavior of a 7 x 7 array of parallel laser beams using a carefully chosen mirror and optic configuration. The beams are reflected off the substrate onto a display screen, thus allowing for the capture of their intensity profiles via a digital camera. Deviations from the original parallel beam path are calculated using a self-programmed image processing package and translated into local and axis curvature values. The apparatus is sensitive to radius of curvature values of up to ~1km (local) and ~5km (axis).

Other facilities can be accessed through the CNS and MRSEC programs at Harvard University.