Chuck Power Research Articles

O2/N2 Plasma Etching of Acrylic in a Multi-layers Electrode RIE System

We investigated dry etching of acrylic (PMMA) in O2/N2 plasmas using a multi-layers electrode reactive ion etching (RIE) system. The multi-layers electrode RIE system had an electrode (or a chuck) consisted of 4 individual layers in a series. The diameter of the electrodes was 150 mm. The etch process parameters we studied were both applied RIE chuck power on the electrodes and % O2 composition in the N2/ O2 plasma mixtures. In details, the RIE chuck power was changed from 75 to 200 W.% O2 in the plasmas was varied from 0 to 100% at the fixed total gas flow rates of 20 sccm. The etch results of acrylic in the multi- layers electrode RIE system were characterized in terms of negatively induced dc bias on the electrode, etch rates and RMS surface roughness. Etch rate of acrylic was increased more than twice from about 0.2 µm/min to over 0.4 µm/min when RIE chuck power was changed from 75 to 200 W. 1 sigma uniformity of etch rate variation of acrylic on the 4 layers electrode was slightly increased from 2.3 to 3.2% when RIE chuck power was changed from 75 to 200 W at the fixed etch condition of 16 sccm O2/4 sccm N2 gas flow and 100 mTorr chamber pressure. Surface morphology was also investigated using both a surface profilometry and scanning electron microscopy (SEM). The RMS roughness of etched acrylic surface was strongly affected by % O2 composition in the O2/N2 plasmas. However, RIE chuck power changes hardly affected the roughness results in the range of 75-200 W. During etching experiment, Optical Emission Spectroscopy (OES) data was taken and we found both N2 peak (354.27 nm) and O2 peak (777.54 nm). The preliminarily overall results showed that the multi-layers electrode concept could be successfully utilized for high volume reactive ion etching of acrylic in the future.

Plasma Etching for Sub-45-nm TaN Metal Gates on High-$k$ Dielectrics

Etching of TaN gates on high-k dielectrics (HfO2 or HfAlO) is investigated using HBr/Cl2 chemistry in a decoupled plasma source (DPS). The patterning sequence includes 248-nm lithography, plasma photoresist trimming, etching of a SiN-SiO2 hard mask, and photoresist stripping, followed by TaN etching. TaN etching is studied by design of experiment (DOE) with four variables using a linear model with interactions. It is found that at a fixed substrate temperature and wafer chuck power, etch critical dimensions (CD) gain decreases with decreasing HBr/Cl2 flow rate ratio and pressure and with increasing source power and total gas flow rate. Based on these DOE findings, subsequent optimization is performed and a three-step etching process is developed; a main feature of the process is progressively increasing HBr/Cl2 flow rate ratio. The optimized process provides etch CD gain within 2 nm and gate profile close to vertical and reliable etch-stop on high-k dielectric. This process is successfully applied to the fabrication of the 40-nm HfAlO/TaN gate stack p-MOSFETs with good electrical parameters

Effect of inductively coupled plasma damage on performance of GaN–InGaN multiquantum-well light-emitting diodes

InGaN multiquantum-well light-emitting diodes (LEDs) in the form of unpackaged die with emission wavelengths from 420to505nm were exposed to either Ar or H2 inductively coupled plasmas as a function of both rf chuck power (controlling incident ion energy) and source power (controlling ion flux). The forward turn-on voltage is increased by both types of plasma exposure and is a function of both the incident ion energy and flux. The reverse bias current in the LEDs is much larger in the case of H2 plasma exposure, indicating that preferential loss of nitrogen leads to increased surface leakage. The current transport in the LEDs is dominated by generation-recombination (ideality factor ∼2) both before and after the plasma exposures.

Study of Selective Etching of GaAs over AlGaAs and InGaP Semiconductors in High Density Planar Inductively Coupled BCl3/SF6 Plasmas

We investigated selective dry etching of GaAs over AlGaAs and InGaP in high density planar inductively coupled <TEX>$BCl_3/SF_6$</TEX> plasmas. The process parameters were ICP source power (0-500 W), RE chuck power (0-30W) and gas composition <TEX>$(60-100\%\;BCl_3\;in\;BCl_3/SF_6)$</TEX>. The process results were characterized in terms of etch rate, selectivities of GaAs over AlGaAs and InGaP, surface morphology, surface roughness and residues after etching. <TEX>$BCl_3/SF_6$</TEX> selective etching of GaAs showed quite good results in this study. Selectivities of GaAs <TEX>$(GaAs:AlGaAs\~36:1,\;GaAs:InGaP\~45:1)$</TEX> were superior at <TEX>$18BCl_3/2SF_6$</TEX>, 20 W RF chuck power, 300 W ICP source power and 7.5 mTorr. Addition of <TEX>$(5-15\%)SF_6\;to\;BCl_3$</TEX> produced relatively high selectivities of GaAs over AlGaAs and InGaP during etching due to decrease of etch rates of AlGaAs and InGaP (boiling points of etch products: <TEX>$AlF_3\~1300^{\circ}C,\;InF_3>1200^{\circ}C$</TEX> at atmosphere) at the condition. SEM and AFM data showed slightly sloped sidewall and somewhat rough surface<TEX>$(RMS\~9nm)$</TEX>. XPS study on the surface of processed GaAs proved a very clean surface after dry etching. It shows that planar inductively coupled <TEX>$BCl_3/SF_6$</TEX> plasmas could be a good candidate for selective dry etching of GaAs over AlGaAs and InGaP.

Inductively coupled plasma etching of Ta, Co, Fe, NiFe, NiFeCo, and MnNi with Cl2/Ar discharges

Dry etching of the magnetic thin films such as Ta, Fe, Co, NiFe, NiFeCo, and MnNi was carried out in inductively coupled plasmas of Cl2/Ar mixture. All the magnetic materials went through a maximum etch rate at 25% Cl2. The effects of the ICP source power and the rf chuck power on the etch rate and the surface roughness were quite dependent of the materials. An ion-enhanced chemical etch mechanism was important for the magnetic films. The surface roughness of the etched samples was relatively constant of the rf chuck power up to 200 W, but a rougher surface at a higher rf power was obtained. Post-etch cleaning of the etched samples in de-ionized water reduced the chlorine residues substantially.

Impact of Ar addition to inductively coupled plasma etching of SiC in SF6/O2

The influence of Ar addition to SF 6 /O 2 gas mixtures has been investigated for inductively coupled plasma (ICP) etching of SiC with a view to improve both etch rate and etched surface microstructure. SiC etch rates have been studied as a function of Ar concentration, gas flow rates, applied ICP power, chuck power and chamber pressure. SiC etch rate, surface morphology, surface chemistry and etch profiles obtained in SF 6 /O 2 /Ar gas mixtures have been compared with those of SiC-etched in SF 6 /O 2 gas mixtures under similar conditions. It was found that, compared with SF 6 /O 2 (4:1) ICP-etched SiC in our studies, smoother surfaces and significant reduction of fluorine-related etch residues can be obtained by optimum Ar addition. SiC etch rate in SF 6 /O 2 gas mixtures can be increased by over 5% with optimum Ar%. The highest SiC etch rate achieved here is approximately 500 nm/min in SF 6 /O 2 /Ar gas mixtures. The influence of Ar addition on the SiC etch profile has also been studied.

Comparison of planar inductively coupled plasma etching of GaAs in BCl 3, BCl 3/Ar, and BCl 3/Ne

The characteristics of GaAs etched using planar inductively coupled plasmas (ICP) of BCl 3, BCl 3/Ar and BCl 3/Ne are reported. The etch rates generally increased with ICP source power and reactive ion etching (RIE) chuck power, while decreasing with increase of pressure. Anisotropic etched features were achieved through sidewall passivation, with a selectivity of GaAs etch rate to a photoresist of ∼3:1. BCl 3/Ar plasmas provided a factor of two times higher etch rate than BCl 3/Ne. Etched surface morphology was generally smooth (RMS roughness<2 nm) RMS roughness was 37.5 nm). XPS showed that the etched GaAs surface was chemically clean and residue-free.

Impact of Ar addition to inductively coupled plasma etching of SiC in SF 6/O 2

The influence of Ar addition to SF 6/O 2 gas mixtures has been investigated for inductively coupled plasma (ICP) etching of SiC with a view to improve both etch rate and etched surface microstructure. SiC etch rates have been studied as a function of Ar concentration, gas flow rates, applied ICP power, chuck power and chamber pressure. SiC etch rate, surface morphology, surface chemistry and etch profiles obtained in SF 6/O 2/Ar gas mixtures have been compared with those of SiC-etched in SF 6/O 2 gas mixtures under similar conditions. It was found that, compared with SF 6/O 2 (4:1) ICP-etched SiC in our studies, smoother surfaces and significant reduction of fluorine-related etch residues can be obtained by optimum Ar addition. SiC etch rate in SF 6/O 2 gas mixtures can be increased by over 5% with optimum Ar%. The highest SiC etch rate achieved here is approximately 500 nm/min in SF 6/O 2/Ar gas mixtures. The influence of Ar addition on the SiC etch profile has also been studied.

Investigation of GaAs Dry Etching in a Planar Inductively Coupled BCl3 Plasma

We investigated dry etching of GaAs in a planar inductively coupled plasma (ICP) reactor with gas chemistry. The process parameters included planar ICP source power, chamber pressure, reactive ion etching (RIE) chuck power, and gas flow rate. The ICP source power was varied from 0 to 500 W. Chamber pressure was changed from 5 to 20 mTorr. RIE chuck power was controlled from 0 to 150 W. The gas flow rate was varied from 10 to 40 sccm. We found that a process condition at 20 sccm 300 W ICP, 100 W RIE, and 7.5 mTorr chamber pressure gave an excellent etch result. The etched GaAs feature showed extremely smooth surface vertical sidewall, relatively fast etch rate (>3000 Å/min) and good selectivity to a photoresist (>3:1). X-ray photoelectron spectroscopy study on the surface of processed GaAs proved a very clean surface of the material after dry etching. We also noticed that our planar ICP source was successfully ignited both with and without RIE chuck power, which was generally not the case with a typical cylindrical ICP source, where assistance of RIE chuck power was required for turning on a plasma and maintaining it. These results indicate that the planar ICP source could be a very versatile tool for advanced dry etching of damage-sensitive compound semiconductors. © 2004 The Electrochemical Society. All rights reserved.

High Density Inductively Coupled Plasma Etching of InP in BCl3-Based Chemistries

We studied InP etching in high density planar inductively coupled and /Ar plasmas(PICP). The investigated process parameters were PICP source power, RIE chuck power, chamber pressure and /Ar gas composition. It was found that increase of PICP source power and RIE chuck power increased etch rate of InP, while that of chamber pressure decreased etch rate. Etched InP surface was clean and smooth (RMS roughness /min) after the planar /Ar ICP etching. It may make it possible to open a new regime of InP etching with -free plasma chemistry. Some amount of Ar addition (

Dry Etching of GaAs and AlGaAs Semiconductor Materials in High Density BCl3 And BCl3/Ar Inductively coupled Plasmas

We investigated dry etching of GaAs and AiGaAs in a high density planar inductively coupled plasma system with BCland BCl/Ar gas chemistry. A detailed etch process study of GaAs and ALGaAs was peformed as functions of ICP source power, RIE chuck power and mixing ratio of and Ar. Chamber process pressure was fixed at 7.5 mTorr in this study. The ICP source power and RIE chuck power were varied from 0 to 500 W and from 0 to 150 W, respectively. GaAs etch rate increased with the increase of ICP source power and RIE chuck power. It was also found that etch rates of GaAs in /5Ar plasmas were relatively high with applied RIE chuck power compared to pure 20 sccm plasmas. The result was the same as AlGaAs. We expect that high ion-assisted effect in /Ar plasma increased etch rates of both materials. The GaAs and AlGaAs features etched at 20 sccm and /5Ar with 300 W ICP source power, 100 W RIE chuck power and 7.5 mTorr showed very smooth surfaces(RMS roughness

Vertical and Smooth, etching of InP by Cl2/CH4/ArInductively Coupled Plasma at Room Temperature

We study the room-temperature dry, etching of InP by inductively coupledplasma (ICP) using Cl2/CH4/Ar mixtures. Etches werecharacterized in terms of anisotropy and surface roughness by scanningelectron microscopy and atomic force microscopy, respectively. It isfound that the flow ratio between Cl2 and CH4, ICP power,rf chuck power, and table temperature can greatly influence the, etchingresults. By adjusting, etching parameters, vertical sidewall and smoothsurface can be obtained simultaneously, together with a moderate, etchrate and a good select ratio. The root-mean-square surface roughness ismeasured to be as low as 0.27 nm. To the best of our knowledge, this is the bestresult for InP to date. The, etch rate is 855 nm/min, and theselectivity ratio over SiO2 is estimated to be higher than 15:1.The stoichiometry of the, etched surface has also been investigated byAuger electron spectroscopy. The, etched surface is found to manifest aslight P deficiency, and the ratio between P and In reaches thestoichiometric value within about 0.75 nm depth into the surface.

플라즈마 식각을 이용한 초전도 자속 흐름 트랜지스터

The channel of a superconducting flux flow transistor has been fabricated with plasma etching method using a inductively coupled plasma etching. The ICP conditions then were ICP Power of 450 W, rf chuck power of 150 W, the pressure in chamber of 5 mTorr, and Ar : Cl<TEX>$_2$</TEX>=1:1. Especially, over the 5 mTorr, the superconducting thin films were not etched. The channel etched by plasma gas showed the critical temperature over 85 K. The critical current of the SFFT was altered by varying the external applied current. As the external applied current increased from 0 to 12 mA, the critical current decreased from 28 to 22 mA. Then the obtained trans-resistance value was smaller than 0.1 <TEX>$\Omega$</TEX> at a bias current of 40 mA.

Dry Etching of GaAs in a Planar Inductively Coupled BCI3 Plasma

We studied BCl<TEX>$_3$</TEX> dry etching of GaAs in a planar inductively coupled plasma system. The investigated process parameters were planar ICP source power, chamber pressure, RIE chuck power and gas flow rate. The ICP source power was varied from 0 to 500 W. Chamber pressure, RIE chuck power and gas flow rate were controlled from 5 to 15 mTorr, 0 to 150 W and 10 to 40 sccm, respectively. We found that a process condition at 20 sccm <TEX>$BCl_3$</TEX> 300 W ICP, 100 W RIE and 7.5 mTorr chamber pressure gave an excellent etch result. The etched GaAs feature depicted extremely smooth surface (RMS roughness < 1 nm), vertical sidewall, relatively fast etch rate (> <TEX>$3000\AA$</TEX>/min) and good selectivity to a photoresist (> 3 : 1). XPS study indicated a very clean surface of the material after dry etching of GaAs. We also noticed that our planar ICP source was successfully ignited both with and without RIE chuck power, which was generally not the case with a typical cylindrical ICP source, where assistance of RIE chuck power was required for turning on a plasma and maintaining it. It demonstrated that the planar ICP source could be a very versatile tool for advanced dry etching of damage-sensitive compound semiconductors.

Inductively coupled plasma etching of SiC in SF6/O2 and etch-induced surface chemical bonding modifications

4H silicon carbide (SiC) substrates were dry etched in an inductively coupled plasma (ICP) system, using SF6/O2 gas mixtures. Etch rate and etch mechanisms have been investigated as a function of oxygen concentration in the gas mixture, ICP chuck power, work pressure, and flow rate. Corresponding to these etch conditions, surface information of the etched SiC has been obtained by x-ray photoelectron spectroscopy measurements. The fact that no obvious Si–Si and Si–F bonds were detected on the etched surface of SiC in all our etch experiments suggests efficient removal of Si atoms as volatile products during the processes. However, various kinds of C–F bonds have been detected on the etched SiC surface and the relative intensities of these bonds vary with the etch conditions. In addition, the nature of the incorporated F atoms on the etched surface also depends strongly on etch conditions, which was identified by the change of the relative ratio between semi-ionic and covalent carbon fluorine bonds. The electrical behavior for different bond structures on the etched SiC surface can be one of the basic reasons affecting related devices.

Comparison of dry etching of AlGaAs and InGaP in a planar inductively coupled BCl[sub 3] plasma

We studied dry etching of AlGaAs and InGaP in a planar inductively coupled BCl3 plasma. The process parameters were planar ICP source power (0–500 W), reactive ion etching (RIE) chuck power (0–150 W), and chamber pressure (5–15 mTorr). The process results were characterized in terms of etch rate, surface morphology, and surface roughness. The planar inductively coupled BCl3 plasmas were also monitored with in situ optical emission spectroscopy (OES). BCl3 planar inductively coupled process (ICP) etching of AlGaAs showed very vertical sidewall, clean and smooth surface, while that of InGaP showed somewhat rough surface after etching. Etch rates of AlGaAs were generally higher than those of InGaP in the planar BCl3 ICP etching. It indicated that InClX byproducts had relatively low volatility during InGaP etching in the planar inductively BCl3 plasmas. Increase of ICP source power and RIE chuck power strongly raised etch rates of both AlGaAs and InGaP. That of pressure decreased etch rate of both materials. OES data showed that emission intensity of the planar BCl3 ICP was a strong function of ICP source power and chamber pressure, while it was almost independent of RIE chuck power.

Dry etching of SrBi2Ta2O9: Comparison of inductively coupled plasma chemistries

A systematic study of the etch characteristics of SrBi2Ta2O9 (SBT) thin films in inductively coupled plasmas (ICPs) has been performed with various chemistries of Cl2/Ar, Cl2/O2/Ar, Cl2/NF3/Ar, and Cl2/NF3/O2/Ar. Etch rate was dependent on plasma chemistries and parameters. Addition of O2 stabilized the perovskite structure of SBT film and suppressed the etch rate, but NF3 enhanced the etch rate substantially mainly due to reactive fluorine radicals. Maximum etch rates obtained were: 740 a/min with Cl2/Ar, 320 a/min with Cl2/O2/Ar, 1,500 a/min with Cl2/NF3/Ar, and 1,600 a/min with Cl2/NF3/O2/Ar at 5 mTorr, 700 W. ICP power and 150 W. rf chuck power. Electrical properties of the SBT films were quite dependent on plasma chemistries employed; Cl2/NF3/O2/Ar showed the least damage in the films and resulted in the best P-E hysteresis loop having remnant polarization (2Pr)=12.3 ΜC/cms2 and coercive field (Ec)=41.9 V/cm.

Deep etch of GaP using high-density plasma for light-emitting diode applications

Deep etching of GaP was performed by high-density plasma using an inductively coupled plasma (ICP) etcher. The effects of process parameters such as the gas combination (Cl2/N2), chamber pressure, inductive power and rf chuck power were investigated. The dependences of the etch rates and selectivity on the rf chunk power and chamber pressure were studied using the response surface method. The results obtained can be further interpreted by the plasma properties (ion flux and dc bias) measured in situ by a Langmuir probe. With an increase in the chamber pressure to 4 Pa, a maximum etch rate of ∼7.5 μm/min for GaP can be obtained under a Cl2/(Cl2+N2) gas mixture of 0.8, ICP power of 800 W, and rf power of 100 W. The increase in the etch rate with an increase in chamber pressure indicates that reactive radicals are the main etching species. To clarify the etching mechanism, the surface reaction of GaP under various Cl2/(Cl2+N2) gas mixtures was investigated by x-ray photoelectron spectroscopy and atomic force microscopy. In addition, quantitative analysis of the plasma-induced damage was attempted in order to discuss the mechanism of leakage current density and brightness with various rf powers on AlGaInP light-emitting diodes with a thick GaP window layer. Under a fixed ICP power applied, it is found that the duration of the plasma (not dc bias voltage) has a major effect on leakage current performance. Finally, an effective recovery method is developed, in which plasma-induced damage can be recovered in a boiling NaOH solution with the range of our experiments.

Effects of Ar inductively coupled plasma exposure on 4H-SiC Schottky rectifiers

4H-SiC Schottky rectifiers were exposed to inductively coupled Ar plasmas as a function of source power (150–750 W), rf chuck power (75–350 W), and process pressure (5–30 mTorr). The reverse breakdown voltage (VB) was increased by increases in both incident ion energy and ion flux, with the former having the strongest influence. As an example, Ar plasma exposure at ion energies of ∼335 eV led to an increase in VB from approximately −500 to −950 V. These results suggest strategies for minimizing plasma-induced damage during both deposition and etching steps used in the fabrication of SiC rectifiers.

Etch characteristics of HfO2 films on Si substrates

The etch rates and mechanisms for HfO2 thin films in Cl2-, SF6- or CH4/H2-based plasmas were measured as a function of source power, r.f. chuck power and discharge composition. Both Cl2- and SF6-based plasmas produced some degree of chemical enhancement in the etch mechanism. Selectivities between 0.2 and 5 were obtained for Si over HfO2 in these two plasma chemistries. High fidelity pattern transfer was achieved for photoresist-masked HfO2/Si structures etched with Cl2/Ar over a broad range of pressures or with SF6/Ar at low pressures. The surface morphologies of both HfO2 and Si were smooth over a wide range of etching conditions.