MICRO:Top 25 (November/December 2002)

The NanoLattice standard is a CD-SEM calibration standard for next-generation semiconductor manufacturing. With a 0.1-µm pitch, the standard enables accurate sub-0.13-µm lithography as well as SEM magnification calibration and characterization of nonlinearity across the field of view. The standard consists of a 1.2 X 1-mm grating etched in silicon with a nominal pitch of 100 nm. When mounted on a wafer, the chip is placed in a recessed pocket so that it is coplanar (±15 µm) to the surface of a wafer. The range of certified pitch values includes 100, 200, 400, 800, and 1000 nm. The product is available in wafer sizes of 300, 200, and 150 mm. A large calibration area of 800 X 800 µm extends product lifetime, since the user is not limited to measuring in the same spot continuously.

Boron Analyzer

A UPW boron analyzer measures parts-per-trillion levels of boron in DI- and ultrapure-water applications. The analyzer performs continuous, on-line, unattended monitoring of ultratrace levels of boron and also can be used to determine the exhaustion of mixed-bed ion-exchange resins. With the parts-per-trillion sensitivity of ICP-MS, the analyzer ensures compliance with primary and polish-loop boron specifications. Because the unit can perform five analyses per hour, engineers can protect against upset conditions that would go undetected with ICP-MS or other batch analysis methods.

X-Ray Diffraction Tools

X-ray diffraction tools for wafers measure epitaxial and nonepitaxial film thicknesses, compositions, and layer roughnesses with high accuracy. Other substrate parameters such as porosity, texture, and stress can be measured as well. The systems use the company's X-Ray Microsource, which provides high x-ray flux on sample spots ranging in size from 500 X 500 µm down to 100 X 100 µm, which makes the tools suitable for performing nondestructive point measurements on monitor wafers and dedicated product wafers. Models are available for automated 300-mm fab lines or for compound semiconductor companies. All systems can be equipped with software for system control and data analysis and are compatible with such front-end modules as FOUPs, SMIFs, or open cassettes.

Bottom Antireflective Coating

Imbarc is a spin bowl–compatible, wet-developable bottom antireflective coating (BARC) suitable for 248-nm implant and front-end processes. The coating is specially formulated for thin photoresist implant applications. Imbarc's optimized substrate reflectance control capability helps to obtain the smaller geometries that result from shrinking critical dimensions. Because the ARC layer eliminates the etch step from the microlithography process by developing Imbarc simultaneously during photoresist development, higher throughput can be achieved. Imbarc is soluble in common photoresist solvents and can therefore be used in the same bowl as the solvents.

A portable fluorine chemical sensor developed for real-time measurements of molecular fluorine (F₂) from parts-per-billion to percentage levels aids in process characterization and the assessment of plasma abatement performance. The sensor's wide dynamic range makes it suitable for applications such as scrubber performance testing, ambient/cleanroom air monitoring, and process pump effluent characterization without cross-contamination from other relative species. The instrument has measurement precision of ±2%, a minimum fluorine detection limit of <50 ppbv, and a response time in the millisecond range.

Polyimide Dispense Unit

The Encompass HV fluid dispense unit provides precise fluid control of high-purity, high-viscosity polyimides. The system's two-stage pump with suckback control allows filtration and dispense operations to occur at independent rates. The unit's dispense function operates at a different rate than its filtration function. By using slower flow rates while filtering, the system reduces gels and bubbles and prevents fluid shear from altering high-molecular-weight polyimides. A three-way recirculation valve ensures continuous fluid motion and reduces viscosity variability. CE certified, the unit offers a programmable controller that manages all fluid-handling functions and enables dispense recipes to be downloaded via a removable handheld terminal.

Wafer Backside Inspection

A fully automated wafer backside inspection system addresses process control needs for advanced design rules and 300-mm applications. The Backside Inspection Module (BSIM) enables nondestructive inspection of the backsides of patterned production wafers with the sensitivity to detect particles as small as 50 nm. As chip fabrication moves to the use of double-sided polished wafers for 300-mm applications, defects on the wafer backside that come to the surface during backside polishing pose a risk of yield losses. Such defects cause front-surface distortion during lithography exposure and can migrate between processes. The BSIM applies the Surfscan SP1 platform to detect and classify a wide range of defect types and decreases the use of unpatterned test wafers. Its edge-only wafer handling is nondestructive to the unscanned side. The tool can be used during all process phases to detect backside defects rapidly with little impact on tool productivity.

Wafer Transfer/Loadlock System

A high-vacuum-compatible, single-substrate loadlock system loads wafers into SEMI-standard or custom process modules. The compact Team-Mate wafer transfer/loadlock system is constructed of carefully selected interfacing materials and has an integrated magnetically coupled transfer device with moving parts located well below the transfer height, minimizing particulates. The transfer device is built into the chamber wall, reducing the system's overall footprint. The unit's valve interface can be easily modified to mate with a wide variety of vacuum systems.

Nanotechnology Stepper

The Model 1600DSA stepper, designed to meet the needs of the nanotechnology market, is based on the 1X 1000-series product line. The fully automated stepper offers 0.8-, 1.0-, and 2.0-µm-resolution lens options. High wafer plane irradiance improves process throughput, especially for thick resists, while low reticle expenses lead to a low cost of ownership. The tool has dual side alignment capability and uses direct vision technology. Based on a proprietary machine vision alignment system, direct vision incorporates an off-axis microscope, which is capable of viewing images on the back of the wafer while exposing features on the front. The tool is supported by a worldwide service and support network.

Liquid Nitrogen Generator

The NitroGen miniature liquid-nitrogen (LN₂) generator helps solve the multiple problems of cryogen availability, transport, inventory, and handling. Because many types of fab equipment are dependent on a continuous supply of LN₂, the issue of availability can become critical. Where existing fab facilities have no provision for plumbed-in LN₂ or where physical layouts make the internal movement of dewars difficult and time consuming, the NitroGen system can generate LN₂ when and where it is needed. Automatic filling of fab tools eliminates manual handling of this dangerous cryogen, thereby reducing the risk of worker injury. Available in several configurations with generating capacities ranging from about 9.6 to 58 L/day, the unit offers reduced particle contamination and high uptime levels.

Proportioning Control Valves

AutoValve products are accurate proportioning control valves that combine a precision stepper motor with a slotted metering valve. The valves can meter media in very precise increments on a repeatable basis. Linear flow characteristics make them suitable for blending or metering applications. With wetted PTFE and PFA surfaces, the valves handle aggressive aqueous reagents and ultrapure media. Added protection is provided by dual PTFE rolling diaphragms and an integral leak detection port. Designed for a closed-loop control system, the valves can be opened or closed to a desired position with a 4- to 20-mA input into the control board, which also monitors a variety of operational parameters. An optional display allows the user to identify performance, setup, and test parameters.

Digital Mass-Flow Controller

The PrimAera digital mass-flow controller (MFC) uses a small-diameter sensor that is very sensitive to changing gas conditions. The core of the unit's electronics is a digital signal processor that operates at 30 MHz, which replaces conventional sensing and control circuits with a digital algorithm, eliminating the drift and inaccuracies associated with analog instruments. The MFC's piezoelectric diaphragm-seated control valve provides fast response times of <1 second. By storing multiple surrogate-gas calibration templates in its memory, the unit allows users to select a wide range of gases without having to recalibrate. That capability makes it possible to reduce MFC inventories.

Immersion Cleaning System

FSI International

Providing high performance at the 100-nm technology node and beyond, the Magellan immersion cleaning system for use in 300-mm manufacturing provides high-throughput processing (up to 30 wafers per hour/m²). The system's use of dilute and ozone chemistries, as well as chemical injection, reduces cycle times by as much as 40%, decreasing learning cycles and increasing order turnaround. In addition to dilute and ozone chemistries, conventional recirculated concentrated chemistries are offered. Surface tension gradient rinse/dry technology with chemical injection is standard. The unit's chemical-blending and delivery technology enables users to switch between multiple chemistries on the same system with no downtime, allowing them to change the product mix easily. STG technology provides watermark-free rinsing and drying, and a short low-IPA consumption process. Advanced process control features enhance process consistency. The fully automated system offers half-pitch, cassetteless processing of up to 52 wafers per batch.

Substrate-Bonding Machine

The Asigs 200, a semiautomatic substrate-bonding machine, performs silicon-on-anything process development and can transfer silicon circuits to glass and other insulating materials. Developed primarily for transfer of 200- and 150-mm wafers, the unit can produce 25 fully bonded wafer units per hour. It aligns silicon and glass wafers to within 0.1 mm of the wafer edge and bonds them with UV-sensitive adhesive. The adhesive is deposited onto the wafers while they are pressed together and rotated, eliminating potential air bubbles and ensuring that the silicon structures are uniformly coated. The adhesive layer is cured with UV illumination and a controlled temperature stage. The tool has a user-friendly interface and real-time display of process parameters.

Wafer-Handling Software

An upgraded software package for the RC-2005 and RC-3005 wafer-handling alignment systems enhances system efficiency. The upgrades are designed for engineers who must assess robot arm position and achieve precise, repeatable alignment settings for different robot types and tool sets. The software helps determine a robot's alignment, find optimum teach values, and transfer those values to other robots. When used for predictive maintenance purposes, it can track alignment data over time, support trend analysis and early warning of failures, produce numeric readouts supporting robot adjustment, engage Auto-Run software to accelerate system start-up, and upgrade paths to extend software usability over a wide range of robots.

Wafer Surface Analyzer

The WM-5000 unpatterned-wafer inspection system for 0.07-µm design rules uses a 400-nm-wavelength laser light source (a violet laser diode). Distributed by Macrotron Process Technologies in Europe, the tool achieves very high detection sensitivity down to 0.041 µm. The system can inspect 100 300-mm wafers/hr at 0.079-µm sensitivity. The instrument's multibeam and polarize optical system offers excellent detection for such new materials as high- and low-k dielectrics, silicon on insulator, and silicon germanium. A strictly mechanical edge-grip handling system supports the wafer to improve coordinate accuracy (<20 µm), minimize the edge exclusion zone, and enable backside inspection.

Yield Management Software

The 3.0 version of dataConductor yield management software has more than 100 new features, upgrades, and enhancements. The Web-based engineering decision support tool is robust and has many automated functions. The new scheduler, when used in conjunction with the enhanced sequencer, allows users to automate typical analysis and reporting steps and have data delivered whenever desired. The autoInsertion feature eases access to data sets from a variety of sources by transforming them into a standard format and storing them in a centralized database. Sophisticated analysis and reporting enhancements enable analysis via a user-specified combination of attributes. Other enhancements to defect density and bin limit analysis, simplified retest yield calculation, and improved insertion and extraction time improve yield management.

Chemical Analyzer

Metara

The LMS-300 chemical constituent analyzer performs fast, direct quantification of inorganic compounds such as copper and chloride, organic additives, and breakdown products in common chemical processing solutions. The tool can generate real-time trend data suitable for correlating back-end yield analysis to chemical processing parameters. The unit performs a range of wet process applications, including electrochemical deposition, electroless deposition, and chemical-constituent analysis. For use in high-volume environments, the system enables the correlation of defects, such as voids and surface irregularities, to the constituents in process chemicals. It also reduces chemical use and minimizes process variations. The fully networked system can be interfaced with a fab's factory automation system. At the push of a button, early-warning signals indicate excursions that can threaten yields.

Thick-Film Quartz Heaters

Based on thick-film technology, ultrapure quartz heater modules for use in semiconductor wet-chemistry applications perform better than inefficient infrared quartz heaters and avoid the permeability problems associated with Teflon-coated products. The heating elements are applied directly onto the exterior surfaces of the quartz tubes, providing efficient transfer of heat energy and enabling rapid response to changes in flow and temperature. The state-of-the-art heaters are for use with aggressive chemicals, such as ammonium hydrochloride, hydrochloric acid, hydrogen peroxide, phosphoric acid, and ultrapure 18-MW DI water. The modules are 50% smaller than competitive heaters and eliminate the risk of process contamination if heating elements fail. The units have a maximum process temperature of 180°C, maximum operating pressure of 75 psi, and a maximum flow rate of 35 L/min. The heaters can be integrated directly into process tools.

Colloidal Silica Slurry

An ammonia-stabilized colloidal silica slurry can be used in both shallow-trench isolation and interlayer dielectric polishing applications. With an average particle size of 40 nm, Ascend slurry contains low levels of metals and sodium and is recommended for CMP applications that may be sensitive to those impurities. The slurry has been tested and proven on both single- and multiplaten tools in the company's laboratories and at customer sites.

Gas Regulator

A manually adjustable HF-series gas regulator has flow rates up to 200 std L/min. A choice of four springs provides outlet pressures ranging from vacuum to 150 psig in a compact design that is approximately half the size of conventional pressure regulators with comparable flow rates. Color-coded load springs are isolated from the wetted components and can be changed in the field without exposing the system to contamination. A pressure-sensing assembly maintains consistent outlet pressure when changes in system pressure and flow rate occur, reducing the need for spring adjustment. The unit, available for inlet pressures up to 500 psig, has a PCTFE poppet for compatibility with a wide range of fluids. It is available with 1/4-in. VCR split-nut assemblies or 1/4-in. tube butt-weld end connections.

300-mm Laser Processing

The second-generation Model 9820, a 300-mm yield improvement system, is used to manufacture DRAM, SRAM, flash, and embedded memory devices. The tool is an enhanced version of the 9800 platform, offering high-speed controllers that boost performance and throughput to 1.5 times that of laser link processing systems. The tool meets throughput, laser spot size, and accuracy requirements beyond the 0.13-µm node. It has the smallest minimum spot size in the industry, and its beam positioning system achieves accuracies of <0.2 µm. The system also features a removable laser and optic table, which allows it to be upgraded to handle future linewidth reductions and dielectric materials. It can be loaded using a variety of automation strategies, including overhead transport systems, automated guided vehicles, and person- or rail-guided vehicles.

ArF Excimer Laser

Cymer

The NanoLith 7000 is a 4-kHz, 20-W ArF production laser for 193-nm next-generation step-and-scan lithography tools. It meets resolution, image contrast, and wafer throughput requirements at the <100-nm nodes. The short wavelength allows chip design to shrink, leading to high processor speed, more memory per chip, and higher yields per wafer. With a line-narrowed bandwidth of <0.35 pm (full-width half-maximum) and 0.95 pm (95% energy integral), the system enables high-contrast imaging from lithography scanners using lenses with a numerical aperture over 0.75. The unit has a pulsed-power design, laser discharge chamber, and wavelength stabilization that ensure tight control of exposure dose and laser wavelength. Built-in laser metrology provides pulse-to-pulse data acquisition and feedback control to minimize transient wavelength instabilities, thereby enhancing exposure latitude and CD control.

Ionized PVD Retrofit Kit

Plasmion

A retrofit kit converts conventional circular or rectilinear magnetron sputter cathodes into negative sputter ion beam sources for an ionized PVD process. The kit, installed at the shield of the sputter cathode, contains a solid-state cesium source, which promotes negative surface ionization. This process helps overcome many limitations of thin-film formation. Advanced atomic-layer coatings can be achieved with atomically smooth surfaces (<1 nm Ra) and strong adhesion. One type of coating is composed of room-temperature indium-tin-oxide (4 X 10^–4 W-cm, 90% transmittance).

Sticky Mat

The 6000M10 Super Kleen Tacky Mat provides strong protection in areas requiring a high degree of contamination control. The mat picks up more foot-borne contaminants and lasts twice as long as conventional hard-surface mats because of its unique contouring and resilient properties. It consists of 10 disposable poly foam sheets. A special poly foam cushion fixed to the base of each mat sheet provides total conformity to the shape of a shoe under normal pressure. Each sheet has bounce-back memory, so that maximum effectiveness is restored after each step. A pressure-sensitive surface picks up all types of dirt and dust from shoes, wheels, and casters. The mat fits into a plastic frame, which is double contoured for trip-free movement. A fresh surface can be exposed by peeling off the contaminated surface. Mat refills are easy to install.

CD-SEM Calibration Standard