• Title/Summary/Keyword: Etch profile

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The Study for Investigation of the sufficient vertical profile with reducing loading effect for silicon deep trench etching (Vertical Profile Silicon Deep Trench Etch와 Loading effect의 최소화에 대한 연구)

  • Kim, Sang-Yong;Jeong, Woo-Yang;Yi, Keun-Man;Kim, Chang-Il
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.06a
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    • pp.118-119
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    • 2009
  • This paper presents the feature profile evolution silicon deep trench etching, which is very crucial for the commercial wafer process application. The silicon deep trenches were etched with the SF6 gas & Hbr gas based process recipe. The optimized silicon deep trench process resulted in vertical profiles (87o~90o) with loading effect of < 1%. The process recipes were developed for the silicon deep trench etching applications. This scheme provides vertically profiles without notching of top corner was observed. In this study, the production of SF6 gas based silicon deep trench etch process much more strongly than expected on the basis of Hbr gas trench process that have been investigated by scanning electron microscope (SEM). Based on the test results, it is concluded that the silicon deep trench etching shows the sufficient profile for practical MOS FET silicon deep trench technology process.

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Prediction of Etch Profile Uniformity Using Wavelet and Neural Network

  • Park, Won-Sun;Lim, Myo-Taeg;Kim, Byungwhan
    • International Journal of Control, Automation, and Systems
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    • v.2 no.2
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    • pp.256-262
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    • 2004
  • Conventionally, profile non-uniformity has been characterized by relying on approximated profile with angle or anisotropy. In this study, a new non-uniformity model for etch profile is presented by applying a discrete wavelet to the image obtained from a scanning electron microscopy (SEM). Prediction models for wavelet-transformed data are then constructed using a back-propagation neural network. The proposed method was applied to the data collected from the etching of tungsten material. Additionally, 7 experiments were conducted to obtain test data. Model performance was evaluated in terms of the average prediction accuracy (APA) and the best prediction accuracy (BPA). To take into account randomness in initial weights, two hundred models were generated for a given set of training factors. Behaviors of the APA and BPA were investigated as a function of training factors, including training tolerance, hidden neuron, initial weight distribution, and two slopes for bipolar sig-moid and linear function. For all variations in training factors, the APA was not consistent with the BPA. The prediction accuracy was optimized using three approaches, the best model based approach, the average model based approach and the combined model based approach. Despite the largest APA of the first approach, its BPA was smallest compared to the other two approaches.

The Etching Characteristics of Cr Films by Using $Cl_{2}O_{2}$ Gas Mixtures ($Cl_{2}O_{2}$ 가스에 의한 크롬 박막의 식각 특성 고찰)

  • 박희찬;강승열;이상균;최복길;권광호
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.14 no.8
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    • pp.634-639
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    • 2001
  • We investigated the etching characteristics of chromium films by using Cl$_2$/O$_2$ gas mixtures with electron cyclotron resonance plasma. In order to examine the chemical etch characteristics of Cr films by using Cl$_2$/O$_2$ gas plasma, we obtained the etch rate with various gas mixing ratios. By X-ray photoelectron spectroscopy, the surface reaction on the chromium films during the etch was examined. From narrow scan analyses of Cr, Cl, and O, it was confirmed that a chromium oxychlorie (CrCl$_{x}$O$_{y}$) layer was formed on the surface by the etch using Cl$_2$/O$_2$ gas mixtures. We observed a new characteristic emission line during the etch of chromium films using Cl$_2$/O$_2$ gas mixtures by an optical emission spectroscopy. It was found that the peak intensity of this emission line had a tendency compatible with the etch rate. The origin of this emission line was discussed in detail. At the same time, the etched profile was also examined by scanning electron microscope.e.e.

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High density plasma etching of CoFeB and IrMn magnetic films with Ti hard mask

  • Xiao, Y.B.;Kim, E.H.;Kong, S.M.;Chung, C.W.
    • Proceedings of the Korean Vacuum Society Conference
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    • 2010.02a
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    • pp.233-233
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    • 2010
  • Magnetic random access memory (MRAM), based on magnetic tunnel junction (MTJ) and CMOS, is a prominent candidate among prospective semiconductor memories because it can provide nonvolatility, fast access time, unlimited read/write endurance, low operating voltage and high storage density. The etching of MTJ stack with good properties is one of a key process for the realization of high density MRAM. In order to achieve high quality MTJ stack, the use of CoFeB and IrMn magnetic films as free layers was proposed. In this study, inductively coupled plasma reactive ion etching of CoFeB and IrMn thin films masked with Ti hard mask was investigated in a $Cl_2$/Ar gas mix. The etch rate of CoFeB and IrMn films were examined on varying $Cl_2$ gas concentration. As the $Cl_2$ gas increased, the etch rate monotonously decreased. The effective of etch parameters including coil rf power, dc-bais voltage, and gas pressure on the etch profile of CoFeB and IrMn thin film was explored, At high coil rf power, high dc-bais voltage, low gas pressure, the etching of CoFeB and IrMn displayed better etch profiles. Finally, the clean and vertical etch sidewall of CoFeB and IrMn free layers can be achieved by means of thin Ti hard mask in a $Cl_2$/Ar plasma at the optimized condition.

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Investigation on Etch Characteristics of FePt Magnetic Thin Films Using a $CH_4$/Ar Plasma

  • Kim, Eun-Ho;Lee, Hwa-Won;Lee, Tae-Young;Chung, Chee-Won
    • Proceedings of the Korean Vacuum Society Conference
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    • 2011.02a
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    • pp.167-167
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    • 2011
  • Magnetic random access memory (MRAM) is one of the prospective semiconductor memories for next generation. It has the excellent features including nonvolatility, fast access time, unlimited read/write endurance, low operating voltage, and high storage density. MRAM consists of magnetic tunnel junction (MTJ) stack and complementary metal-oxide semiconductor (CMOS). The MTJ stack is composed of various magnetic materials, metals, and a tunneling barrier layer. For the successful realization of high density MRAM, the etching process of magnetic materials should be developed. Among various magnetic materials, FePt has been used for pinned layer of MTJ stack. The previous etch study of FePt magnetic thin films was carried out using $CH_4/O_2/NH_3$. It reported only the etch characteristics with respect to the variation of RF bias powers. In this study, the etch characteristics of FePt thin films have been investigated using an inductively coupled plasma reactive ion etcher in various etch chemistries containing $CH_4$/Ar and $CH_4/O_2/Ar$ gas mixes. TiN thin film was employed as a hard mask. FePt thin films are etched by varying the gas concentration. The etch characteristics have been investigated in terms of etch rate, etch selectivity and etch profile. Furthermore, x-ray photoelectron spectroscopy is applied to elucidate the etch mechanism of FePt thin films in $CH_4$/Ar and $CH_4/O_2/Ar$ chemistries.

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Dry Etching of Al2O3 Thin Film by Cl2/Ar Plasma (Cl2/Ar 플라즈마를 이용한 Al2O3 박막의 식각)

  • Yang, Xue;Um, Doo-Seung;Kim, Gwan-Ha;Song, Sang-Hun;Kim, Chang-Il
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.12
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    • pp.1005-1008
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    • 2009
  • In this study, adaptively coupled plasma (ACP) source was used for dry etching of $Al_2O_3$ thin film. During the etching process, the wafer surface temperature is an important parameter to influent the etching characteristics. Therefore, the experiments were carried out in ACP to measuring the etch rate, the selectivities of $Al_2O_3$ thin film to mask materials and the etch profile as functions of $Cl_2$/Ar gas ratio and substrate temperature. The highest etch rate of $Al_2O_3$ was 65.4 nm/min at 75% of $Cl_2/(Cl_2+Ar)$ gas mixing ratio. The etched profile was characterized using field effect scanning electron microscopy (FE-SEM). The chemical states of $Al_2O_3$ thin film surfaces were investigated with x-ray photoelectron spectroscopy (XPS).

Scanning System Method for Calculating Ion Flux in Plasma Etching Simulation (플라즈마 식각 시뮬레이션을 위한 스캔 방식의 이온 플럭스 계산 방법)

  • Shin, Sung-Sik;Yu, Dong-Hun;Gwun, Ou-Bong
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.10
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    • pp.124-131
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    • 2013
  • The most important thing in Plasma simulation is the etching process in which etch rate is calculated based on feature profile. Although there are various components to consider in calculating etch rate such as Ion Flux, Neutral, gas, and temperature, Addressing of this paper is limited to Ion Flux. This paper propose a scan method to compute Ion Flux faster for Plasma simulation. Also, this paper experiments and compares generally used Monte Carlo method and the proposed method based on gaussian and cosine distribution. Lastly, this paper proves that the proposed method can calculate accurate Ion Flux more efficiently than Monte Carlo method.

GaN Dry Etching Characteristics using a planar Inductively coupled plasma (평판형 유도 결합 플라즈마틀 이용한 GaN 건식 식각 특성)

  • Kim, Moon-Young;Kim, Tae-Hyun;Jang, Sang-Hun;Tae, Heung-Sik
    • Proceedings of the KIEE Conference
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    • 1997.11a
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    • pp.276-278
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    • 1997
  • The reliable etching process is one of the essential steps in fabricating GaN based-device. High etch rate is needed to obtain a deeply etched structure and perfect anisotropic etched facet is needed to obtain lasing profile. In the research, therefore, we had proposed a planar inductively coupled plasma etcher (Planar ICP Etcher) as a high density plasma source, and studied the etching mechanism using the $CH_4/H_2$/Ar gas mixture. Dry etching characteristics such as etch rate, anisotropic etching profile and so on, for the III-V nitride layers were investigated using Planar ICP Etcher, based on the plasma characteristic as a variation of plasma process parameters.

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Random generator-controlled backpropagation neural network to predicting plasma process data

  • Kim, Sungmo;Kim, Sebum;Kim, Byungwhan
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • 2003.09a
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    • pp.599-602
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    • 2003
  • A new technique is presented to construct predictive models of plasma etch processes. This was accomplished by combining a backpropagation neural network (BPNN) and a random generator (RC). The RG played a critical role to control neuron gradients in the hidden layer, The predictive model constructed in this way is referred to as a randomized BPNN (RG-BPNN). The proposed scheme was evaluated with a set of experimental plasma etch process data. The etch process was characterized by a 2$^3$ full factorial experiment. The etch responses modeled are 4, including aluminum (Al) etch rate, profile angle, Al selectivity, and do bias. Additional test data were prepared to evaluate model appropriateness. The performance of RC-BPNN was evaluated as a function of the number of hidden neurons and the range of gradient. for given range and hidden neurons, 100 sets of random neuron gradients were generated and among them one best set was selected for evaluation. Compared to the conventional BPNN, the proposed RC-BPNN demonstrated about 50% improvements in all comparisons. This illustrates that the RG-BPNN of multi-valued gradients is an effective way to considerably improve the predictive ability of current BPNN of single-valued gradient.

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The Influence of He flow on the Si etching procedure using chlorine gas

  • Kim, J.W.;Park, J.H.;M.Y. Jung;Kim, D.W.;Park, S.S.
    • Proceedings of the Korean Vacuum Society Conference
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    • 1999.07a
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    • pp.65-65
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    • 1999
  • Dry etching technique provides more easy controllability on the etch profile such as anisotropic etching than wet etching process and the results of lots of researches on the characterization of various plasmas or ion beams for semiconductor etching have been reported. Chlorine-based plasmas or chlorine ion beam have been often used to etch several semiconductor materials, in particular Si-based materials. We have studied the effect of He flow rate on the Si and SiO2 dry etching using chlorine-based plasma. Experiments were performed using reactive ion etching system. RF power was 300W. Cl2 gas flow rate was fixed at 58.6 sccm, and the He flow rate was varied from 0 to 120 sccm. Fig. 1 presents the etch depth of si layer versus the etching time at various He flow rate. In case of low He flow rate, the etch rate was measured to be negligible for both Si and SiO2. As the He flow increases over 30% of the total inlet gas flow, the plasma state becomes stable and the etch rate starts to increase. In high Ge flow rate (over 60%), the relation between the etch depth and the time was observed to be nearly linear. Fig. 2 presents the variation of the etch rate depending on the He flow rate. The etch rate increases linearly with He flow rate. The results of this preliminary study show that Cl2/He mixture plasma is good candidate for the controllable si dry etching.

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