摘要:

Designed experiments were employed to characterize a process for etching phosphorus doped polycrystalline silicon with HBr in a close‐coupled electron cyclotron resonance plasma reactor configured for 200 mm wafers. A fractional factorial screening experiment was employed to determine the principal input factors and the main etch effects. Linear models of the process responses indicate rf power, O2flow rate, and the position of the resonance zone (with respect to the wafer) as the three strongest factors influencing process performance. Response surfaces generated using data from a follow‐on response surface methodology experiment predicted an optimum operating region characterized by relatively low rf power, a small O2flow, and a resonance zone position close to the wafer. One operating point in this region demonstrated a polysilicon etch rate of 270 nm/min, an etch rate nonuniformity of 2.2% (1 std. dev.), an etch selectivity to oxide greater than 100:1, and anisotropic profiles. Particle test results for the optimized process indicated that careful selection of the O2fraction is required to avoid residue deposition and particle formation.  

ISSN:1071-1023    

DOI:10.1116/1.587137

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

High aspect ratio etching of polyimide in an O2plasma generated by an electron cyclotron resonance (ECR) source was investigated. The dependence of etch rate, profile, and selectivity on microwave power, rf power, pressure, etch time, and gas composition were characterized. Etch rate was found to increase with microwave and rf power. Etch anisotropy increases with rf power but decreases with pressure and etch time. With 750 W microwave power, 300 W rf power, and 0.5 mTorr pressure, the polyimide etch rate was 0.91 μm/min and the anisotropy was 0.92. Etch selectivity between polyimide and the Ti mask was 3150:1 at 50 W and 536:1 at 300 W rf power. Compared to reactive ion etching, etching using an ECR source provides etch rate that is typically 10× faster and etch selectivity that is 4–6× higher. High aspect ratio (≳15:1) structures in polyimide that were 50 μm deep and 3 μm wide have been obtained using an O2plasma generated by an ECR source.

ISSN:1071-1023    

DOI:10.1116/1.587138

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

0.5 μm complementary metal–oxide–semiconductor structures were utilized to investigate the selective nature of a high density plasma reactor. The formation of borderless contacts and local interconnects by the selective etch stop film approach was discussed and shown to be affected by topography, planarization, and nonuniformities. A factorial design of experiments determined the optimum conditions of the selective oxide etch chemistry. The resulting etch chemistry was characterized by measurable quantities such as an oxide etch rate of 1200 nm/min, a patterned (0.5 μm image) etch‐rate ratio for oxide:nitride ≳100:1 and 5%‐3σ uniformity. And, finally, an integratedinsituoxide etch/resist strip/nitride etch was presented.

ISSN:1071-1023    

DOI:10.1116/1.587139

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

An ultrahigh vacuum electron cyclotron resonance (ECR) plasma source has been used to deposita:Si, Si3N4, SiNx, SiOxNy, and SiO2dielectric thin films on InP and related compound semiconductors for optoelectronic applications. Films are deposited without substrate heating using mixtures of SiH4, N2, O2, and Ar. Following deposition, thermomechanical properties have been studied by annealing to 450 °C in N2. High temperature film stability is strongly influenced by the addition of Ar to the gas mixture, indicating an important role of ion bombardment during film growth by ECR plasma chemical vapor deposition. In addition, for applications as optical coatings for photonic devices, film refractive index can be accurately controlled by the N2/O2/Ar flow rate ratios.

ISSN:1071-1023    

DOI:10.1116/1.587140

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Silicon dioxide films deposited by electron cyclotron resonance chemical vapor deposition have been characterized using Fourier transform infrared spectroscopy, Rutherford backscattering spectrometry, and ellipsometry. A commercially available reactor was used to generate a high‐density plasma at low total gas pressures (3–4 mTorr). A gas mixture of Ar, O2, and SiH4was used to deposit SiO2films on 200 mm Si substrates at temperatures less than 450 °C for interlayer dielectric applications. The dielectric constant of the films was measured using metal oxide semiconductor capacitors. Relationships between the dielectric constant and the refractive index, Si–OH content, and film stoichiometry were investigated using a model based on the Clausius–Mosotti equation. During the study, the O2and SiH4gas flows were adjusted to vary the film properties. Silicon dioxide was deposited over a wide range of O2and SiH4gas flow conditions. For SiO2films, the dielectric constant was strongly correlated with the Si–OH content. At low O2/SiH4gas flow ratios, suboxide films were deposited and the dielectric constant increased in relation to the refractive index. A low‐temperature, postdeposition anneal was investigated as a means to reduce the Si–OH content and dielectric constant of the films. Modeling results indicate that the dielectric constant of SiO2films can be predicted using measurements of the film thickness, refractive index, and Si–OH content, thus providing a nondestructive technique for monitoring the dielectric constant.

ISSN:1071-1023    

DOI:10.1116/1.587141

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A technique has been developed for highly efficient postionization of sputtered metal atoms from a magnetron cathode. The process is based on conventional magnetron sputtering with the addition of a high density, inductively coupled rf (RFI) plasma in the region between the sputtering cathode and the sample. Metal atoms sputtered from the cathode due to inert gas ion bombardment transit the rf plasma and can be ionized. The metal ions can then be accelerated to the sample by means of a low voltage dc bias, such that the metal ions arrive at the sample at normal incidence and at a specified energy. The ionization fraction, measured with a gridded mass‐sensitive energy analyzer is low at 5 mTorr and can reach 85% at 30 mTorr. Optical emission measurements show scaling of the relative ionization to higher discharge powers. The addition of large fluxes of metal atoms tends to cool the Ar RFI plasma, although this effect depends on the chamber pressure and probably the pressure response of the electron temperature. The technique has been scaled to 300 mm cathodes and 200 mm wafers and demonstrated with Cu, AlCu, and Ti/TiN. Deposition rates are equal to or in some cases larger than conventional magnetron sputtering. A primary application of this technique is lining and filling semiconductor trenches and vias on a manufacturing scale.

ISSN:1071-1023    

DOI:10.1116/1.587142

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A high density inductively coupled plasma (ICP) polycide etcher was studied by incorporating it into a 0.5 μm complementary metal–oxide–semiconductor process flow having a nominal 10 nm gate oxide. Polysilicon: oxide etch selectivity, sidewall profile, and critical dimension control were found to be good. Gate oxide damage was studied in detail using both antenna and large capacitor test structures in area‐ and edge‐intensive configurations. No charge buildup was detected using the antenna structures, and damage measured using large capacitors was also very low. Damage was found to be insensitive to bias power, while the sequence of extinguishing the plasma had a small effect. An experimental hardware modification significantly reduced the level of subintrinsic failures of gate edge‐intensive capacitors. Split‐lot comparisons were made of several etchers using standard hardware and processes, and the rf ICP etcher was found to result in significantly lower oxide damage than the split‐power rf triode, plasma‐mode rf diode, or microwave electron cyclotron resonance etchers studied. The lowest damage occurred in the ICP, followed by the diode. Langmuir probe measurements were made of plasma potential and ion current for the bulk etch and overetch processes used in the ICP etcher; the results are compared to wafer maps of oxide damage. Plasma potential and ion current are very uniform in this plasma, and no pattern is evident from the wafer maps of breakdown failures. The low oxide damage measured using the ICP etcher probably results from the combination of hardware and process design that ensures a uniform plasma.

ISSN:1071-1023    

DOI:10.1116/1.587100

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Inductively coupled plasma sources are being developed to address the need for high plasma density (1011–1012cm−3), low pressure (a few to 10–20 mTorr) etching of semiconductor materials. One such device uses a flat spiral coil of rectangular cross section to generate radio‐frequency (rf) electric fields in a cylindrical plasma chamber, and capacitive rf biasing on the substrate to independently control ion energies incident on the wafer. To investigate these devices we have developed a two‐dimensional hybrid model consisting of electromagnetic, electron Monte Carlo, and hydrodynamic modules; and an off line plasma chemistry Monte Carlo simulation. The results from the model for plasma densities, plasma potentials, and ion fluxes for Ar, O2, Ar/CF4/O2gas mixtures will be presented.

ISSN:1071-1023    

DOI:10.1116/1.587101

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A two‐dimensional (r,z) fluid model has been developed to study plasma transport in inductively coupled plasmas (ICP). Electron heating is treated by assuming a fixed, spatially varying power deposition profile in the electron energy balance equation. A high aspect ratio ICP reactor geometry has been studied, with two assumed power profiles: spatially uniform and localized to within several skin depths of the radial wall. The effect of neutral gas pressure on plasma uniformity is presented for an argon discharge over the range of 1–20 mTorr. Comparisons between the fluid model and predictions from a spatially averaged global model show similar scaling of plasma density, electron temperature, and plasma potential over a wide range of pressure and power.  

ISSN:1071-1023    

DOI:10.1116/1.587102

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Calculations of the forces experienced by particles in high density plasma sources such as an electron cyclotron resonance system indicate that particles can accelerate in the plasma and travel through sheaths. This is due primarily to the very high ion fluxes in these systems and relatively low sheath potentials. The net result is less particle trapping and growth in the plasma compared to conventional plasma sources. The temperature of the particles is calculated from an energy balance. The particles heat due to electron‐ion recombination on their surface, and they cool by radiation and conduction to the neutral gas. Because of the high plasma density and low neutral pressure, the particles may reach high temperatures (T∼1000 K).

ISSN:1071-1023    

DOI:10.1116/1.587103

出版商:American Vacuum Society    

年代:1994

数据来源: AIP