EOS/ESD Symposium for Factory Issues

Wednesday, November 7, 2012 Technical Session 1A
1A.1: Issues & Solutions Involving Tape & Reel Induced ESD
Jane Pan, Donna Robinson, Fairchild Semiconductor
Presenting a study of ESD issues due to high charging but reportedly ESD safe tape and reel materials. This study includes both novel and industry standard testing of many types of tape and reel materials, a variety reported and potential issues due to the improper tape and reel materials, and proposed test standards to avoid these issues.

1A.2: Humidity Control Device for Static Charge Reduction
Albert Kow Kek Hing, ESD Consultancy, Sdn. Bhd.
This paper relates to a device comprising a moisture generation and delivery system to reduce or minimize static charges at any target area without the use of any air ionizer. Apart from keeping electrostatic voltages at safe levels, this device functions like a maintenance free ionizer hence realizing substantial cost savings.

1A.3: S20.20 ESD Improvements for the Factory Floor
Richard Wong, Cisco Systems Inc.; Desmond Liu, 3M Corp.; Kum Weng Loo, Peter Gabrovsky, Xilinx Corp.
As component IO data rate increase, the component ESD protection is limited by the amount of capacitance that can be attached to IO. Thus, the handling of high speed components in the factory floor is becoming more critical. This paper will discuss factory floor issues that are not currently addressed by s20.20 but can lead to ESD handling issues.

1A.4: "Volume Conductive" Polyurethane and Epoxy Sealings and Thick Coatings Meet the Latest ESD Standards
Gerhard Kraus, StoCretec GmbH
Generally there are two ways to carry out an ESD flooring in an EPA. Depending on the requirements, floor coverings based on synthetic rubber or PVC as well as floor coatings based on epoxy or polyurethane resins are used. Since commercial carbon fiber loaded floor coatings often are having problems in meeting the latest ESD standards (e.g. Rtg via person/footwear/floor and walking test according to IEC 61340-5-1 [1] and ANSI/ESD S20.20-2007 [2]) their reputation is not the best. This paper gives information about the reasons, why common floor coatings have this non ideal behavior and provides solutions, achievable by applying advanced Epoxy- or Polyurethane sealings on top of the floor coatings or by using so called "volume conductive coatings" instead.

Technical Session 1B
1B.1: EOS Risk to Thin Oxides Contributed by Wrist-Strap Monitors
Scott Ward, Soo Leng Tan, Texas Instruments
Wrist straps have long been used to protect devices from electrostatic discharges (ESD). Constant monitoring wrist straps ensure, in real-time, that operators are properly grounded while handling devices. These same monitors, however, have been found to generate voltages at levels that put thin oxides at risk for EOS damage.

1B.2: CDM Risk Mitigation with Air Ionization in Hi-Temp Automated Test Handler
Yohan Goh, Marcus Koh, Everfeed Technology Pte. Ltd.
Mass volume testing of semi-conductor devices using automated handling equipment (AHE) has prevailed for more than two decades. This has brought tremendous costs benefit; increase productivity and fast turn-around time for semi-conductor manufacturers. The underlying Charge Device Model (CDM) risks leading to catastrophic failure or latency issues with testing of Electrostatic Discharge Sensitive (ESDS) Devices in AHE, remain a well-known phenomenal widely reported by industry. Technology scaling and the ever-increasing demand on device operating speed pose a severe challenge to maintain the sensitivity of ESDS devices on-chip protection. There remain lots of existing and functional AHEs in semi-conductor manufacturers' test floor, built many years ago where there were little or no considerations on charge mitigation on testing of ESDS devices. This paper narrates fifty units of existing high temperature (Hi-Temp) AHE test handlers for high pin count ESDS Devices. The Hi-Temp AHE was designed and built more than 20-years ago, which remains functional but unable to meet new stringent AHE ESD customer specifications. The new AHE ESD requirements can be accomplished by understanding the need, customized design, installation and implementation with new novel concept in Hi-Temp air ionization and minimize risk of CDM whilst testing.

1B.3: Process ESD Compatibility Measurements
Arnold Steinman, Electronics Workshop and Dangelmayer Associates
There are no standards for establishing compatibility of a manufacturing process with the handling of devices of known ESD sensitivity. A prior paper established that voltages measured on components could correlate to device testing voltages. This paper makes measurements on different devices and people to compare with voltages and discharges of HBM and CDM testing.

Technical Session 1C
1C.1: Experiences with an Alternative Method for Grounding Personnel During Sitting Operation
CY Wong, CT Ong, KP Yan, Infineon Technologies
One of the major requirements for safe handling of IC´s is the grounding of personnel. The paper presents data about the effectiveness of using the floor/footwear system as primary means of grounding personnel in standing and sitting operation. It also discusses whether there is a contradiction with International Standards like IEC 61340-5-1 or ANSI/ESD S20.20.

1C.2: A Comparison of Electrostatic Discharge Models and Failure Signatures for Light-Emitting Diode
Gim Wae Goh, Osram Optos Semiconductor; Yohan Goh, Marcus Koh, Everfeed Technology Pte. Ltd.
ESD failures can occur in ESD protected areas in manufacturing environment that are well designed according to the latest ESD standards like ANSI S20.20 [1] or IEC 61340-5-1 [2]. The root cause for the failures can normally only be found by a detailed analysis of the whole production flow [3, 4].

1C.3: Implementing Air Ionizing Blower at KLA Tencor 2401 Metrology Tool Reduce Visual Inspection Failure for Semiconductor Wafers
Harriman Razman, Mohd Faizal Adris, Cha Tree Tow Woon, Silterra Malaysia Sdn. Bhd.
This paper describes the methodologies use for implementing effective air-ionizing blower at KLA Tencor 2410 (Viper) metrology tool for removing particles from outgoing wafers. After the implementation of this air-ionizing blower, achieved reduction of wafer lot failed visual inspection from 21.4% to 4.1% in Q2'2011.

Thursday, November 8, 2012 Technical Session 2A
2A.1: Investigating The Performance of Vacuum Formed Conductive and Dissipative trays Which are used for Handling and Storage of ESDS
Rainer Pfeifle, Wolfgang Warmbier GmbH & Co. KG
Vacuum formed trays are widely used in electronic production for handling and storage of ESD sensitive electronic circuits. Thee circuits are sensitive to electrostatic discharges and /or to electrostatic fields. ESDS in contact with surfaces shall dissipate their charge in a defined time to ground potential. While checking vacuum formed trays during ESD audits in many different locations, we have realized that a significant quantity of the trays when tested inside the cavities, do not comply with the standards recommendations regarding the safe handling of ESDS. This report shows test results of a vacuum formed tray that had been produced out of three different Polystyrene materials for a product qualification.

2A.2: ESD Levels and Trends for Advanced Memory Technologies
Yvonne Yeo Chii, Ang Ai Kiar, Jung Yoon, IBM
This paper presents a benchmarking study which was conducted to investigate the impact of aggressive technology scaling on the ESD levels of Advanced Memory Technologies. ESD qualification data were collected from various suppliers for DRAM and NAND Flash Memory technologies. The technology nodes range from 90nm down to 40nm for DRAMs and 60nm down to 25nm for Flash devices. The package types used were FBGAs for DRAMs and TSOP and LGAs for NAND Flash devices.

2A.3: Novel Strap to Achieve Less Than 50 Volt HBM on Normal Footwear
Albert Kow Kek Hing, ESD Consultancy, Sdn. Bhd.
HBM voltage control to a level of below 50 volts consistently has been difficult if not impossible in a manufacturing environment without wrist-strap in standing operations. By the addition of a stainless steel element into a custom designed foot grounder, a wearer can achieve typically less than 10 volts HBM consistently.

2A.4: Comparing Room Ionization Technologies in FPD Manufacturing
Joshua Yoo, Core Insight, Inc.; Dongsun Kim, JuYung Jeong, WonJoon Ho, LG Display Co., Ltd.; Arnold Steinman, Electronics Workshop
In FPD manufacturing, handling charges both sides of the glass panels. Ionizing bars over the top of the panels have a limited effect on ESD and particle contamination as the bottom of the glass remains charged. This paper examines charge generation in FPD manufacturing and proposes alternative ionization technology.

Technical Session 2B
2B.1: Reduction of Coupled Voltage of Electric Cable with Electro-Static Countermeasure
Takayoshi Ohtsu, Kentaro Hayashida, Yusaku Kobayashi, Shogo Imai, Shunsuke Okada, Suzuka National College of Technology; Yorioki Matsumoto, Matsumoto Giken Co. Ltd.
The failure by an electric noise caused by Electrostatic discharge (ESD) is one of the most important causes of reliability problems. It is important to reduce the fluctuation in a voltage of power supply for electric equipment. The metal covered cable is used to reduce an electric noise. It is effect on a shield of the electromagnetic wave because of the electric resistance on the surface of this cable is low. However, it is afraid of a fluctuation in a voltage due to the electrostatic discharge with the electric charged metal object. On the other hand, the insulation covered cable is used generally. It is afraid of a fluctuation in a voltage due to the electrostatic discharge by a tribo-charge. In this paper, the dissipative material covered cable was studied to reduce the fluctuation in a voltage.

2B.2: Compliance Verification of Static Dissipative Carrier for ESDS Devices in Semiconductor Backend Testing
Edmund Seah, Micron Semiconductor Asia Pte. Ltd.; Yohan Goh, Marcus Koh, Everfeed Technology Pte. Ltd.
In the semiconductor manufacturing testing environment, electrostatic sensitive (ESDS) semiconductor package is always being transported around in an electrostatic safe carrier. This is clearly stipulated in ANSI/ESD S20.20-2007 Section 8.3 "ESD protective packaging shall be in accordance with the contract, purchase order, drawing or other documentation". This carrier will hold the ESDS package and transfer within Tri-Temp Test Handler(s) probes for testing before being removed from the carrier to the customer tray. These ESD safe carriers are usually made out of thermal plastic that has ability to withstand extreme temperature from -55 OC to 150OC. With these properties, Polyetherimide (PEI) and Polyethersulfone (PES) are most widely used.

2B.3: Evaluation of the Performance of Corona and Hybrid Alpha Ionizer Technology in Air and Nitrogen
Larry Levit, LBL Scientific; Geoff Weil, Anodyne Research
Ionizing pure Nitrogen is problematic, yet N2 applications are common. This study identified the charge carriers created by corona and hybrid Alpha ionizers and explained the voltage imbalances. It showed how to control them and make a stable N2 ionizer with hybrid Alpha technology. The positive charge carriers in N2 are N+ and the negative charges are free electrons with a small some Azide ions,_N_. Since electrons are 4 orders of magnitude lighter than that of Nitrogen atoms, the free electrons achieve much higher speeds than the ions and create a huge voltage imbalance when electrostatic forces drive the charge carriers. Voltage imbalance was measured for blower and bar type corona ionizers as well as for Alpha-based ionizers. The mechanisms for the imbalances are discussed.Extremely high voltages are required to create the free charges by corona and the same voltage is used to electrostatically propel the charge carriers away from the ionizer. In the case of Alpha source-based ionizers, the mechanism for liberating charge carriers is collisional and requires no high voltage. For a hybrid Alpha-electrical ionizer, there is no voltage threshold constraint for creating ions and a highly asymmetric voltage waveform is shown to deliver the charge carriers with excellent voltage balance. This cannot be achieved using the corona effect because the voltage threshold required to create ions, eliminates the option of asymmetric waveforms.

Technical Session 2C
2C.1: EMI-Caused EOS Exposure of Components and Its Mitigation
Vladimir Kraz, OnFILTER, Inc.
Increasing sensitivity of today's components brings issue of electrical overstress (EOS) to the front, lines of efficient high-yield manufacturing. One of the main causes of EOS is electrical noise (EMI). This paper investigates the sources of EMI in electronic manufacturing and methods of mitigation of EOS exposure.

2C.2: HBM Concerns on Semiconductor Component (ICs) Mounted in Frame Form During Backend Manufacturing Processes
KK Ng, CY Wong, KP Yan, Infineon Technologies
At semiconductor backed manufacturing flow, before the "trim and form" process, IC components are mounted in frame form. Study had been carried out to determine the risk of ICs being damaged due to HBM ESD event through both grounded lead frame and (ungrounded) lead frame.

2C.3: ESD Control at Tape Drive and Tape Head Manufacturing
Johan Jr. Chan, Ruby Soliman, Michelle Lam, Rabic Hameed, IBM
ESD control program specifically designed for the ultra-sensitive magnetic tape head and drive manufacturing is described. The usage of a customized designed Discharge Event Audit (DEA) tool to implement ESD control is demonstrated. The importance of ESD control on the supplier side was also emphasized in the paper through DEA experiment demonstration.

2C.4: Minimizing Electrostatic Charge Generation and ESD Event in TFT-LCD Production Equipment
Dong-Sun Kim, Cun-bae Lim, Du-Seok Oh, Won-Joon Ho, Ju-Young Jeong, LG Display
In TFT LCD manufacturing processes, electrostatic charge generates when glass is separated from stages and its amplitudes closely related with vacuum pressure to holds the glass, holding times, separation cycles, lift pin height, lift speed and other various conditions throughout in the most TFT LCD processes. This paper examines how electrostatic generations are related between these factors. Also, glass lift pin materials should be insulators rather than static dissipative or conductive to protect ESD events. Residual charges on glass must be neutralize by ionizers to control ESD damage by separation from stage materials.

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