Recent advances in silicon etching for MEMS using the ASE™ process

Hynes, A.; Ashraf, Huma; Bhardwaj, J. K.; Hopkins, Janet; Johnston, Ian; Shepherd, Jennifer N. Hanson

doi:10.1016/s0924-4247(98)00326-4

Cited by 165 publications

(105 citation statements)

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“…A 3-m-thick layer of resist was deposited, patterned into a staircase layout by contact lithography, and hard-baked to act as a surface mask. The silicon was then etched to 100 m depth in an inductively coupled plasma etcher using a cyclic etch-passivation process (see, e.g., [9]). After etching, residual resist was stripped in a plasma asher.…”

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confidence: 99%

External cavity laser with a vertically etched silicon blazed grating

Lohmann¹,

Syms²

2003

IEEE Photon. Technol. Lett.

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Abstract-An external cavity laser based on a stripe waveguide semiconductor optical amplifier, a ball lens, and a blazed diffraction grating fabricated by vertical deep reactive ion etching of silicon is demonstrated. Bandpass characteristics for a 12th-order grating are given. Tuning of an external cavity laser over a 120-nm spectral range is demonstrated, with a maximum single-mode fiber-coupled power of 1 mW and side-mode suppression ratio of 30 dB.Index Terms-External cavity, grating, microelectromechanical systems, semiconductor laser. GREAT interest has been shown in frequency-tunable narrow line sources for optical communications [1]. One possible approach is to use a monolithic source such as a multisection distributed Bragg reflector laser. An alternative is offered by an external cavity source, which may allow a simpler and more stable tuning algorithm. Such sources are based on a movable reflective filter. Vertical-cavity surface-emitting lasers (VCSELs) equipped with multilayer dielectric mirrors have been developed by Bandwidth 9 Inc. [2] and Core Tek Inc. [3]. However, VCSELs suffer from the disadvantage of low output power compared with stripe-emitting devices, and require simultaneous development of the gain block and tuning mechanism.External cavity lasers based on conventional stripe-waveguide semiconductor optical amplifiers (SOAs) and piezoelectrically actuated blazed gratings were originally developed in the late 1980s by BTRL [4] and CNET [5]. More recently, SOAs have been combined with mirrors [6], [7] and gratings [8] on micromachined electrostatic actuators by NTT and Iolon, respectively. The advantages of this approach are a reduction in size and cost, combined with an improvement in stability and reliability.The most common geometries for an external cavity laser based on an SOA are the Littrow and Littman/Metcalf configurations, shown in Fig. 1(a) and (b), respectively. The former involves a single pass through a blazed grating, and the latter a double pass through a reflection grating via a further external mirror. In each case, rotation of a key component about a well-chosen virtual pivot point can avoid longitudinal mode hopping. Littrow cavities with conventionally fabricated blazed gratings were used by BTRL, and Littman cavities by Iolon. In this letter, we demonstrate a laser based on a vertically etched silicon blazed grating arranged in a Littrow cavity. The fabrication approach used may allow eventual integration of the grating with a suitable positioning actuator. In the Littrow configuration, retro-reflection occurs when , where is an integer order, is the optical wavelength, is the grating period, and is the incidence angle. Gratings were designed for operation at m, with different values of (1.5 2, 3 2, 6 2, and 9 2 m, corresponding to 2nd, 4th, 8th, and 12th order at ). The fabrication process was very simple. A 3-m-thick layer of resist was deposited, patterned into a staircase layout by contact lithography, and hard-baked to act as a surface mask. The silicon was then...

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confidence: 99%

External cavity laser with a vertically etched silicon blazed grating

Lohmann¹,

Syms²

2003

IEEE Photon. Technol. Lett.

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“…Using wafers of 100 mm diameter, each wafer yields sufficient dies A hard mask layer consisting of a thick layer of Shipley AZ9260 photoresist is first deposited on the substrate side, and patterned with the outer layer features (Mask #1). This pattern is transferred through the substrate to the oxide interlayer (Step 2), using a Surface Technology Systems Single-chamber Multiplex inductively coupled plasma (ICP) etcher, operating a variant of the cyclic etch-passivate process based on and developed by Robert Bosch GmbH [31], [33]. The etch selectivity is .…”

Section: Fabrication Of Prototypesmentioning

confidence: 99%

Monolithic MEMS quadrupole mass spectrometers by deep silicon etching

Geear¹,

Syms

Wright³

et al. 2005

J. Microelectromech. Syst.

105

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“…The best performance is obtained on insulating substrates [10]. However, modest performance can be obtained on intrinsic silicon, allowing low-cost structuring by deep reactive ion etching (DRIE), a method of near vertical etching which operates by a cyclic repetition of etching and passivation processes [11]. DRIE has a high rate (> 2 µm/min), and may etch through a 500 µm thick wafer in under 4 hours.…”

Section: Related Contentmentioning

confidence: 99%

Micro-coils for MR spectroscopy by deep silicon etching

Syms¹,

Ahmad²,

Young³

et al. 2005

J. Phys.: Conf. Ser.

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A process for batch fabrication of low-cost microcoils for magnetic resonance spectroscopy is demonstrated. Conductors are fabricated on oxidised silicon substrates by electroplating metals inside a deep photoresist mould, and passivated using an epoxy-based resist. Through-wafer deep reactive ion etching is used to define sample volumes and stencil cuts around each die, and dies are separated by snap-out. Single-coil and multiple-coil sensors are constructed by stacking parts on baseplates fabricated on the same wafer. Single-turn coils have a Q-factor of ≈ 15 at 63.6 MHz, and Helmholtz coils a Q-factor of ≈ 13. Magnetic resonance imaging and spectroscopy are performed, and a SNR of 900 is achieved.

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Recent advances in silicon etching for MEMS using the ASE™ process

Cited by 165 publications

References 1 publication

External cavity laser with a vertically etched silicon blazed grating

External cavity laser with a vertically etched silicon blazed grating

Monolithic MEMS quadrupole mass spectrometers by deep silicon etching

Micro-coils for MR spectroscopy by deep silicon etching

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