High Rate Plasma Etcher for Wafer Damage Removal and Thinning

Introduction

For 20 years Secon has been manufacturing dry etch equipment for the production of discrete components and integrated circuits.

These equipments are being used in different markets such as

• damage removal and passivation for diodes and rectifiers
• wafer damage removal after grinding processes
• high rate dry etching for wafer thinning and damage removal

Application

Damage removal from mechanically ground wafers for stress relief, warpage/bow removal and edge rounding without ion bombardement.

Wafer thinning down to > 50 µm including damage removal.

Deep trench etching for die separation for thin substrates without mechanical stress and chipping for Si and III-V materials

Features

• Soft wafer handling
• Fastest etch rate available
• Low temperature
• Good Etch uniformity
• Good Surface Quality
• Low Cost of Ownership

200mm Wafer

Technology

Secon developed the new high rate Slim etch technology on the basis of the Secon radical generator using a combined CDE / RIE / UV (Chemical Dry Etch / Reactive Ion Etch / Ultra Violet radiation) fluorine process with an etch rate for silicon of > 20 µm/min for the whole wafer surface and > 40 µm/min for deep trench etching on structured wafers.

Equipment

The XPL-900 SLIM multichamber dry etcher is a modular production system for high rate dry etching. It can be equipped with up to 4 process chambers.

The basic platform consists of a load-lock-chamber with wafer handler and a control unit. It permits the connection of up to 6 chambers (pro-cess chambers, load- and unload chambers).

The control unit consists of microprocessor boards for the machine functions and a personal computer for process control, administration and the dialogue with the operator.

The process chambers are designed for up to 300 mm wafers for high rate thinning, damage removal and deep trench etching.

The gas system for each process chamber consists of three electropolished and orbitally welded stainless steel ¼“ process g as lines, one ¼“ He gas line and an inert gas line for purging with submicron filter, MFC, and bellows sealed shut off valve.

The vacuum system has a pressure regulating system with a pendulum shut off and control valve. Pressure measurement by a capacitance pressure gauge. The recommended vacuum pump is a 1200 m³/h dry pump (e. g. Ebara AAS 200 WN).

Wafer handling Several options for handling of wafers of different thickness are available such as cassette to cassette for thick wafers or cassette to jar pack with interleaf paper for wafers to be thinned from 150 to 50 µm.

Specifications

Utilities per Etch Module (Process Chamber)

Physical Parameters

A cost-effective plasma processing system for Reactive Ion Etching and/or Plasma Enhanced Chemical Vapor Deposition

The BENCHMARK 800-II® Plasma Processing System from Axic, Inc. defines a new concept in RIL and PECVD plasma processing Systems. The system is based on a modular design starting with a universal chamber and cabinet unit with Planar, RIP and PECVD electrode modules available for easy installation into the chamber unit. We're confident you'll find the ease of use, variety of plasma processes, serviceability and attractive pricing of the BENCHMARK 800-II® unsurpassed by any other plasma product on the market.

System Description

In the research and devel-opment of plasma processing, there has always been a great need for a highly versatile and reliable tool. With ever changing requirements in plasma research, the system selected must offer the widest range of process parameters, a high degree of repeatability for process verification, and must he easily modified for new process requirements.

We believe that the BENCHMARK 800-II® series of dry process systems satisfies these very demanding requirements.

The BENCHMARK 800-Il® is a plasma tool used in research, process development or low volume production for precise etching and deposition on substrates up to eight inches in diameter. The system can be operated in either a batch or single slice mode.

In designing the BENCHMARK 800-II®, the prime directive was to create a system that incorporates the quality, reliability, repeatability and process control capabilities of dedicated production-oriented systems, while drastically reducing cost, maintenance and floor space requirements.

The BENCHMARK 800-II®'s unique cabinet and electrode design allows for easy installation in a laminar flow module or cleanroom. Selection of proven, quality components, modular subassemblies, versatile chamber and electrode design, compact size, automation and field-proven process recipes make the BENCHMARK 800-II® from Axic, Inc. the plasma engineer's "system of choice."

Features

• Single-piece chamber construction
• In-situ electrode spacing (PECVD version)
• Replaceable gas showerhead
• Proven process recipes
• Field-proven components
• Endpoint detection (option)
• Multiple electrode configurations
• Auto RF matching
• Downstream pressure control (option)
• Computer control with Windows programming
• Multiple pumping options: mechanical, mechanical/blower, turbo
• Single chamber and dual chamber versions

Applications

With its generous seTection of processing modules, the BLNCHMARK 800-II® satisfies a broad range of plasma processing conditions, from sophisticated submicron RIE etching to deposition of high quality PECVD films. A list of typical processes is shown below.

Working closely with our large customer base, we have developed field-proven process recipes, guaranteeing that your system will be up and run ning from the day you install it. Only the highest quality subcomponents are used in manufacture, ensuring that your BENCHMARK 800-II system will provide the highest possible uptime, reliability, repeatability and serviceability.

• Failure analysis applications
• Material modification
• Adhesion promotion Plasma descum
• Surface treatment
• Anisotropic and isotropic etching
• Metal etching
• Si0₂, Si₃N₄ and SiO_xN_y deposition
• III-V etching applications
• Trench etching
• Passivation etching
• Polyimide etching
• Submicron etching

Specifications

The popularity of the BENCHMARK 800-II® is due primarily to its attractive cost of ownership and a highly versatile design, providing features and process benefits not found on most systems. These include a small footprint for laminar flow installations and multiple electrode configurations. Substrates up to eight inches in diameter can be processed.

Basic system

Basic components in the BENCHMARK 800-II® system include a Windows-based PC controller with recipe storage, two channels of mass flow control with expansion of up to six channels, temperature compensated capacitance manometer for measurement of process vacuum, 1OOmm vacuum plumbing for maximum process gas conductance, KF or ISO, fittings for ease of service, plus many other processing and service features. Gas lines are stainless steel with VCR connections.

Process Chamber

The BENCHMARK B00-II®s aluminum process chamber is constructed from a unique "single-piece" design. RIE, PECVD and Parallel Plate systems use the same chamber design. The chamber's upper portion contains the top electrode and is available with in-situ variable electrode spacing. The lower portion contains the substrate electrode, the vacuum pumping port and all necessary valves and vacuum monitoring equipment. An automatic hoist raises the upper portion of the chamber for easy access to the lower electrode.

Electrodes

The RIE series of electrodes are specifically designed for maximum performance in the lower vacuum ranges. The stainless steel upper electrode contains the "showerhead" gas delivery system. The stainless steel bottom electrode is temperature controlled via an optional recirculating liquid bath. The RIE cathode is supplied with a dark space shield, confining the plasma between the two electrodes. The PECVD electrodes are of similar design. However, the aluminum lower substrate electrode is capable of being heated to 400°C, while the upper electrode (powered) is water cooled. The aluminum electrode has a gas induction port for rapid cool down after completion of deposition. For PFCVD applications the upper electrode spacing can be continuously varied between 1" and 3.5".

Plasma sources

A broad range of power and plasma frequences is available. All power sources are solid state and air cooled wherever possible. Available power ranges from 300 to 1250 Watts and RF frequencies from 40 KHz to 2.45 GHz, with 13.56 MHz/6OO watts being standard. Aut o or manual matching networks are supplied where necessary.

Process pumping

The system is supphed either with a mechanical pump, mechanical pump and turbomolecular pump, or mechanical pump with Roots Blower, depending on process requirements. Various sizes of these pumps are available based on the required vacuum processing levels.

Controller

A Pentium computer is employed for complete system control. This includes a hard drive, 1.44MB floppy disk drive'e, 8MB DRAM and a clock-calendar. Complete Windows software using multiple display windows for equipment control, datalogging, recipe setup and storage, and system interlocking is provided.

Options

To further increase its capabilities, the BENCHMARK 8OO-II® offers a broad selection of available processing options, including endpoint detection, water chillers, oil filtration and purging systems, downstream pressure control and hard-anodized chamber. Exhaust gas abatement systems can also be supplied.

The dual chamber system can be configured in any combination of RIE and PECVD. While a RIE/PECVD combination is the more obvious for versatility, a PECVD/PECVD combination is useful in avoiding cross-contamination for different deposition processes.

Dimensions

Weight

150-250 lbs. (depending on options).

Utilities

Modular Electrodes For Use With Axic's MULTIMODE® Series Plasma Systems

Axic's MultiMode Plasma Processing Systems, through the use of easily insertable electrodes, provide a versatility not found on any other plasma system. Each electrode style is mounted on a seal plate and is inserted into the rear of the plasma chamber. The seal plate is then attached to the chamber through the use of thumbscrews and sealed via an o-ring seal. It only takes a few minutes to completely change the plasma process by changing the electrode configuration.

The available electrode configurations, Reactive Ion Etching (RIE) and Cage provide the user with a wide variety of plasma processing capabilities within one cost effective system. These processes ange from sophisticated RIE processing to surface cleaning and material modification. All MultiMode systems are designed with easily interchangeable chamber modules available in a variety of materials. You may select from Aluminum, Anodized Aluminum or 304 SST for chemistry or process compatibility. All chamber modules are designed to accept any electrode configuration providing a system designed for the users specific processing requirement. Axic's MultiMode interchangeable electrode concept is described in detail as follows:

RIE Electrode Configurations

This electrode configuration allows the user to perform sophisticated Reactive Ion Etching and Planar Plasma Etching. The electrodes consist of two rectangular water cooled parallel plates. The upper electrode contains an easily removable gas showerhead for uniform gas dispersion.

Features

• Temperature Controlled
• Electrodes
• 304 SST Construction
• 13.56 MHz RF Power
• Removable Gas Showerhead
• Quartz or Graphite Cathode
• Cover Plates
• Either Electrode Can Be RF Powered

Applications

• RIE Etching
• Failure Analysis
• Descumming
• Delineation
• Material Modifications

CAGE Electrode Configurations

This electrode configuration allows the user to "batch process" substrates for a wide variety of plasma applications. The electrode consists of a cylindrical tube (cathode) of perforated aluminum in which the substrates are placed. The plasma is generated between this tube and the chamber wall. Process gas is admitted to the chamber via a gas dispersion tube running the length of the chamber.

Features

• Large Processing Area
• Uniform Plasma Generation
• Uniform Gas Dispersion
• 13.56 MHz RF Power

Applications

• Photoresist Str ipping
• Descumming
• Surface Modification
• Substrate Cleaning
• Biomedical Applications

TRAY Electrode Configurations

This electrode configuration allows the user to process flat subtrates, in a horizontal position, on a series of shelves that can either be at ground potential or RF powered. Process gas is admitted to the chamber via a gas dispersion tube running the length of the chamger.

Features

• Substrates Grounded or RF Powered
• Multiple Trays for Larger Process Area
• Horizontal Processing for Uniformity
• Unifform Gas Dispersion
• 40 KHz or 13.56 MHz RF Power

Applications

• Descumming
• Hybird Clearning
• Surface Treatment & Modification
• Adhesion Promotion
• Biomedical Applications