Geometry Design of Vertical Probe Needle using Mechanical Testing and Finite Element Analysis

Kwon, Hyock-Ju,Lee, Jiwon,Shin, Bonghun,Jeon, Soo,Han, Chung Su,Im, Chang Min Korean Society for Precision Engineering 2014 International Journal of Precision Engineering and Vol.15 No.11

In wafer probing, probe needles provide the physical contact between the wafers and the probe card. During the contact process, the shape of the probe needle and the mounting configuration onto the probe card has large influences on the stresses and contact force that the probe needles experience. In this paper, static performance of a vertical-type probe needle integrated with floating mount technology was analyzed with a nonlinear finite element analysis. The geometry of a vertical probe needle was optimized in order to minimize the stress that occurs during the overdrive process, while maintaining adequate force for proper contact with the wafer. Maximum stress and contact force were formulated using the coefficients of 4th order polynomial representing the shape of cobra body, and then curvature of the probe needle body was optimized by applying the constrained minimization function to these functions. The maximum stress in the vertical probe pin at <TEX>$125{\mu}m$</TEX> overdrive was reduced from 972 MPa to 666 MPa by employing the probe needle with optimized geometry. The optimized design also induced the contact force of 5.217 gf, which is in the range of the required contact force of 5 to 8 gf.

피로수명과 가공공차를 고려한 수직형 탐침의 형상 설계에 관한 연구

박종현(J. H. Park),이종길(J. K. Lee) 한국소성가공학회 2010 한국소성가공학회 학술대회 논문집 Vol.2010 No.5

Probe card of the vertical probe design is one of the very important issue for meet the high density. Maintaining a stable electrical contact is required to secure the appropriate contact force for wafer inspection probe. The probe of the wafer bonding pad oxide destroyed by the electrical contact resistance of less than 1Ω is to meet the level. Another thing to consider is the fatigue life cycle of an important requirement Probe. Wafer Probe and contact the bonding pad to the internal stress by calculating the value of the life of the expected fatigue life cycle, the process of expression is necessary. Wafer inspection probe to forecast the lifetime of the probe stress-fatigue criterion using life prediction based on the shape of the probe. To meet these performance for Wafer Inspection Probe for the shape of the finite element analysis to design and perform the test of life. Finite element analysis and the shape of the Wafer Inspection Probe relevance to the contact force and stress, and, when calculated using the stress and fatigue life prediction, compared with the test results verify the validity of that. This study suggested the consideration of fatigue life of the wafer probe in a systematic way to design a vertical probe card can be used effectively to improve the quality and performance is expected.

Geometry Design of Vertical Probe Needle using Mechanical Testing and Finite Element Analysis

권혁주,이지원,Bonghun Shin,Soo Jeon,Chung Su Han,임창민 한국정밀공학회 2014 International Journal of Precision Engineering and Vol. No.

In wafer probing, probe needles provide the physical contact between the wafers and the probe card. During the contact process, theshape of the probe needle and the mounting configuration onto the probe card has large influences on the stresses and contact forcethat the probe needles experience. In this paper, static performance of a vertical-type probe needle integrated with floating mounttechnology was analyzed with a nonlinear finite element analysis. The geometry of a vertical probe needle was optimized in orderto minimize the stress that occurs during the overdrive process, while maintaining adequate force for proper contact with the wafer. Maximum stress and contact force were formulated using the coefficients of 4th order polynomial representing the shape of cobrabody, and then curvature of the probe needle body was optimized by applying the constrained minimization function to these functions. The maximum stress in the vertical probe pin at 125 μm overdrive was reduced from 972 MPa to 666 MPa by employing the probeneedle with optimized geometry. The optimized design also induced the contact force of 5.217 gf, which is in the range of the requiredcontact force of 5 to 8 gf.

Study on Estimation Method for Maximum Temperature of Multi-layered Micro-probe by Joule-Heating

Hyun-Woo Jung,Yun-Jae Kim,박준협 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.10

In this study, a method which would improve reliability of coated vertical type micro-probe under Joule heating is described. The method is to decouple the mechanical and electrical characteristics of a probe. That is, the method is to coat a metal with good electrical characteristics on a core metal with a good mechanical characteristics by electroplating. For various configurations of cross-sectional area of probe, FE analysis are performed, and a fabricated vertical micro-probe is tested to improve the accuracy of FE analysis. By increasing the coating thickness of a metal (gold, Au) with good electrical characteristics by electroplating while keeping a total cross-sectional area of a probe constant, the maximum temperature of probe continues to decrease as the cross-sectional area of core metal (nickel, Ni) with the good mechanical characteristics is reduced. A simple formula to predict the maximum temperature of probe depending on the coating thickness based on the results of FE analysis is proposed. The formula describe that the maximum temperature of the probe by Joule heating is a function of the ratio of the conductivity of the coating metal to the core metal and the ratio of the cross-sectional area of the coating metal to the total cross-sectional area of the probe.

4-포트 수평/수직 겸용 프로브용 교정키트

김태호(Taeho Kim),김종현(Jonghyeon Kim),김성준(Sungjun Kim),김광호(Kwangho Kim),푸보(Bo Pu),나완수(Wansoo Nah) 한국전자파학회 2014 한국전자파학회논문지 Vol.25 No.5

본 논문에서는 4-포트 수평/수직 프로브 스테이션을 사용하여 수직 커넥터 핀의 특성 측정 시 사용되는 회로망 분석기의 교정용 키트(calibration kit)를 제안한다. 기존의 수평면에서 사용되는 교정키트를 사용하면, 교정 후 프로브 암의 변경 및 추가적인 장치가 필요하며, 이로 인한 시간 소요뿐 아니라, 주변 상황에 민감한 프로브 팁의 위치 변동에 기인한 정밀도 훼손의 위험이 있다. 본 논문에서는 이를 보완할 수 있는 4-포트 수평/수직 겸용 교정키트를 제시한다. 교정은 SOLT 방법을 이용하였으며, Short, Open, Load는 수평면에서 교정하며, Thru는 프로브의 위치에 따라서 교정기판의 같은 수평면에서 교정하거나 또는 교정기판의 위쪽, 아래쪽을 수직으로 연결하여 사용할 수 있도록 설계/제작하였다. 즉, 기판에 수직한 Thru를 교정할 때에는 교정키트를 수직으로 세워 키트 양면을 사용하여 교정할 수 있는 방법을 제안하였다. 제안한 교정키트에서의 SOLT 회로 반사/전달 특성을 기존 교정키트의 SOLT 회로의 반사/전달 특성과 비교 분석하였으며, 두 교정키트의 전달 특성은 길이 보정 후, 300 kHz부터 8.5 GHz까지 약 ±0.1 dB의 차이가 있음을 확인할 수 있었다. 이와 같이 설계/제작된 4-포트 수평/수직 교정키트의 유용성을 입증하기 위하여 각각 수평 측정의 경우와 수직 측정의 경우의 두 가지 경우 사례 연구를 수행하였으며, 그 결과를 기존의 교정키트를 사용한 후 측정된 결과 데이터와 비교 분석하였다. In this paper, we propose a horizontal/vertical calibration kit for calibrating a vector network analyzer(VNA) to measure the vertical connector pin. If the conventional calibration kit is used, we should change the arm for a probe or need an assistant device and it takes a long time. In addition there is a risk of precision degradation caused by the position change of the probe tip sensitive to the surroundings. We suggest a 4-port vertical calibration kit to make up for the aforementioned shortcomings. The calibration kit was manufactured for the SOLT calibration method. ‘Short’, ‘Open’, and ‘Load’ are available in the horizontal plane, ‘Thru’ is available not only in the horizontal plane on the two planes of a PCB, but in the vertical plane between the two planes according to the positions of the probes. We complemented the conventional calibration kit to make a vertical calibration kit to be used for the vertical measurement method. We compared and analysed their reflection/transfer characteristics of the SOLT calibration standards of the proposed calibration kit and conventional one, we get a ±0.1 dB differences of transfer characteristics in the range from 300 kHz to 8.5 GHz. In order to demonstrate usefulness, and we performed a case study for horizontal and vertical cases, and compared the results of the proposed calibration kit and conventional one.

응력 및 표면 고장물리를 고려한 MEMS 신뢰성 설계 기술

이학주(Hak-Joo Lee),김정엽(Jung Yup Kim),이상주(Sang Joo Lee),최현주(Hyun Ju Choi),김경식(Kyung Shik Kim),김장현(J.-H Kim) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5

As semiconductor and MEMS devices become smaller, testing process during their production should follow such a high density trend. A circuit inspection tool probe card makes contact with electrode pads of the device under test (DUT). Nowadays, electrode pads are irregularly arranged and have height difference. In order to absorb variations in the heights of electrode pads and to generate contact loads, contact probes must have some levels of mechanical spring properties. Contact probes must also yield a force to break the surface native oxide layer or contamination layer on the electrodes to make electric contact. In this research, new vertical micro contact probe with bellows shape is developed to overcome shortage of prior work. Especially, novel bellows shape is used to reduce stress concentration in this design and stopper is used to change the stiffness of micro contact probe. Variable stiffness can be one solution to overcome the height difference of electrode pads.

Remote Gating of Schottky Barrier for Transistors and Their Vertical Integration

최영진,김성찬,조정호 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

The remote gating relies on the sensitive work function of graphene, whose local variation induced by locally applied field effect affects the change in the work function of the entire material. Using Kelvin probe force microscopy analysis, we directly visualize how this local variation in the work function propagates through graphene. These properties of graphene are exploited to assemble remote-gated vertical Schottky barrier transistors (v-SBTs) in an unconventional device architecture. Furthermore, a vertical complementary circuit is fabricated by simply stacking two remote-gated v-SBTs (pentacene layer as the p-channel and indium gallium zinc oxide layer as the n-channel) vertically. We consider that the remote gating of graphene and the associated device architecture presented herein facilitate the extendibility of graphene-based v-SBTs in the vertical assembly of logic circuits.

환형채널 내 저압 미포화비등 유동장의 국소 이상유동 변수 측정

이연건(Yeon-Gun Lee),유지웅(Ji-Woong Yoo),김신(Sin Kim) 대한기계학회 2018 大韓機械學會論文集B Vol.42 No.12

대기압 주변 저압조건에서 미포화비등 유동장 내 국소 기포인자를 측정하기 위한 실험 연구를 수행하였다. 시험부는 유효 가열길이 2 m의 수직 환형채널이며, 기포변수의 측정에 광섬유센서를 적용하였다. 네 군데의 높이에서 국소 기포율, 평균 기포속도, 계면면적밀도, Sauter mean diameter를 측정하였으며, 광섬유센서의 측정 팁을 이송함으로써 각 높이에서의 반경방향 단면 분포를 획득하였다. 실험에서 유동 조건은 열속 370 kW/m², 질량속 430~680 kg/m²s, 입구 과냉각도 12~18 K, 그리고 압력 114~152kPa의 범위로 조절하였다. 국소 기포인자의 다차원 분포 측정 결과는 전산유체역학 코드의 벽면 비등모델 검증에 유용하게 활용될 수 있다. In this study, an experimental investigation is performed to measure the local bubble parameters in steam-water subcooled boiling flow under atmospheric pressure conditions. The test section is a vertical concentric annulus with an effective height of 2 m, and optical fiber probes are used to measure various local bubble parameters during boiling of the subcooled flow. The local void fraction, mean bubble velocity, interfacial area density, and Sauter mean diameter are measured at four elevations, and their radial profiles are obtained by traversing the tip of optical probes. In the experiments, the flow conditions were set for a heat flux of 370 kW/m², a mass flux of 430~680 kg/m²s, and an inlet subcooling of 12~18 K at pressures ranging from 114 to 152 kPa.

고밀도 프로빙 테스트를 위한 수직형 프로브카드의 제작 및 특성분석

민철홍,김태선,Min, Chul-Hong,Kim, Tae-Seon 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.9

As an increase of chip complexity and level of chip integration, chip input/output (I/O) pad pitches are also drastically reduced. With arrival of high complexity SoC (System on Chip) and SiP (System in Package) products, conventional horizontal type probe card showed its limitation on probing density for wafer level test. To enhance probing density, we proposed new vertical type probe card that has the $70{\mu}m$ probe needle with tungsten wire in $80{\mu}m$ micro-drilled hole in ceramic board. To minimize alignment error, micro-drilling conditions are optimized and epoxy-hardening conditions are also optimized to minimize planarity changes. To apply wafer level test for target devices (T5365 256M SDRAM), designed probe card was characterized by probe needle tension for test, contact resistance measurement, leakage current measurement and the planarity test. Compare to conventional probe card with minimum pitch of $50{\sim}125{\mu}m\;and\;2\;{\Omega}$ of average contact resistance, designed probe card showed only $22{\mu}$ of minimum pitch and $1.5{\Omega}$ of average contact resistance. And also, with the nature of vertical probing style, it showed comparably small contact scratch and it can be applied to bumping type chip test.

Handy Calibration Substrate for both Horizontal and Vertical Probing

Bo Pu,Taeho Kim,Jinho Joo,Wansoo Nah 대한전자공학회 2021 Journal of semiconductor technology and science Vol.21 No.2

This article proposes a novel substrate for a handy SG-GS/SG-SG calibration in both horizontal and vertical probing measurement. The proposed substrate provides two ways of probing for “through” calibration in horizontal and vertical positions without changing the probe holders. It has “through” lines vertically and horizontally using vias and traces, respectively, and both “through” lines were designed to satisfy 50 ohms of characterization impedance. A prototype of the proposed substrate was fabricated using FR4 and then tested in the horizontal calibration resulting in the successful reproduction of all the S-parameters in the horizontal meander test board. It was also tested in the vertical calibration, and was successful to re-produce all the coupling effects in via arrays, demonstrating the effectiveness and handiness of the proposed calibration substrate.