摘要:

As semiconductor technology moves toward reduced feature size, increased device density, and larger diameter wafers, there is increasing need for reliable, economical,insitu, single‐wafer processing under low‐thermal budget conditions. Two promising techniques to do this are rapid thermal processing and remote plasma‐enhanced chemical vapor deposition. The integration of such processing techniques together with proper surface preparation has significant potential for meeting the fabrication needs at the deep submicron level. The extension of suchinsituprocessing to include the clustering of multiple processing tools is another step in the development of low‐thermal‐budget,insitu, single‐wafer processing. Such cluster tools require the development of well‐controlled high throughput technologies that are cost effective and compatible with high‐yield manufacturing.

ISSN:1071-1023    

DOI:10.1116/1.587186

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Engineering models, based on computational fluid dynamics, have been developed and used to improve the performance of two metalorganic chemical‐vapor‐deposition reactors. Though the knowledge of the chemical reactions occurring during film deposition is incomplete, the models provide insight into the reactor’s performance and are useful in guiding reactor modifications. In one reactor, the effect of three gas injector designs on the film thickness uniformity is examined; in a second reactor, the shape and placement of a flow deflector, which redistributes the flow of gas over the wafer surface, is studied. In both cases, comparing the experimental results obtained both before and after the reactor modifications, significant improvements in film thickness uniformity were realized.

ISSN:1071-1023    

DOI:10.1116/1.587187

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Particle formation from Si and SiO2substrates in Ar sputtering plasmas and CCl2F2/Ar reactive ion etching (RIE) plasmas has been investigated using laser light scattering, electron microscopy, and optical emission spectroscopy. Nearly spherical particles with sizes down to 50 nm are collected downstream from the substrate even before the onset of light scattering or at pressures below the threshold for cloud formation. Si atoms are seen readily by optical emission during sputtering, but not during RIE, of both Si and SiO2. The rate of particle formation correlates with the density of Si atoms in the plasma. Hence, it is suggested that Si atoms are probably the species responsible for particle nucleation in sputtering and RIE, and formation of a particle cloud occurs only when the transport of Si atoms out of the sheath edge region becomes inefficient, as evidenced by redeposition in sputtering and by polymerization in RIE.

ISSN:1071-1023    

DOI:10.1116/1.587188

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

The waste gases in low‐pressure chemical vapor deposition and plasma enhanced chemical vapor deposition semiconductor processes react strongly with residual air in the exhaust of the vacuum pump to form solid deposits. It is common practice to purge the exhaust line with pure nitrogen to reduce the concentration of ambient air between the pump and the scrubber to an acceptable low level. However, the unexpected high quantities of exhaust deposits found in some systems cannot be explained by air leaks, impurities in the nitrogen, or diffusion. The problem of anomalous exhaust deposit formation was examined experimentally. A 40 mm pipe, up to 5 m in length and initially filled with nitrogen, was connected to an 80 m3/h dry vacuum pump exhausting to air at atmospheric pressure. The composition of the atmosphere in the pipe was analyzed with a mass spectrometer. Under static conditions, the gas density distribution was ultimately limited, as expected, by simple interdiffusion. When the pump was running, however, there was a dramatic enhancement of the oxygen concentration throughout the pipe. The experimental observations were interpreted in terms of Richardson’s annular effect. It is shown that the pressure fluctuations typical of vacuum pumps are responsible for the enhanced counterflow of air. The effect can be reduced by applying nitrogen purge but, even with a moderate 20l/min flow rate, deposits can form due to air transported back from the scrubber or exhaust duct.

ISSN:1071-1023    

DOI:10.1116/1.587189

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

The trends within the electronic industry toward decreasing device dimension and increasing integrated circuit device density are driving developments in analytical technology. The lateral resolution and sensitivity of present generation analytical equipment are challenged by device feature dimensions. In addition, acceptable contamination levels are decreasing. Some of the analysis methods facing this challenge are total reflection x‐ray fluorescence, ellipsometry, Auger microprobe, and secondary‐ion‐mass spectrometry. Networked analytical systems are presently used to improve cycle time for analysis. This type of system allows a focused ion beam tool or a scanning electron microscope to quickly move to previously located electrically active defect. The focus of this presentation will be on the challenges facing materials characterization and failure analysis methods. The discussion will include the effect of networked analytical systems on both problem solving methodology and the potential role of new characterization methods such as heavy‐ion backscattering spectrometry and post‐ionization of sputtered neutrals.  

ISSN:1071-1023    

DOI:10.1116/1.587190

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Real‐time sensors are key for flexible manufacturing environments where variable layer structures are processed concurrently. We have developed a high speed spectral ellipsometer capable of precisely measuring thicknesses and compositions of multilayer structuresinsituand in real‐time (i.e., the time frame of process changes or about one second). This spectral ellipsometer has been integrated into several vacuum chambers of a flexible process flow. Utilizing phase modulation, multichannel detection, and digital signal processing techniques, less than 0.5 s is required for acquisition of 46 spectral points. Fast numerical algorithms and processor are used for reducing measured spectral ellipsometric data to physical parameters (i.e., thicknesses and compositions), in real time based on a ‘‘standard model’’ approach. Implementations of spectral ellipsometric sensing in rapid thermal oxidation and remote plasma etch are described. For thermally activated processes such as oxidation, temperature dependent dielectric functions have been employed for analyzing samples at process temperatures as high as 1100 °C. Multilayer combinations of Si3N4, SiO2, Si3N4plus SiO2mixtures, and polycrystalline Si have been monitored and thicknesses controlled.

ISSN:1071-1023    

DOI:10.1116/1.587191

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Competitive pressures in the integrated circuit (IC) industry are now requiring short time‐to‐market product introductions. With the most successful of these products ultimately reverting to commodity status, it is also becoming important to be able to convert from flexible manufacturing within a facility set up for engineering assisted processing to low‐cost volume production as experience is gained. Computer‐based design for manufacturability (DFM) of the IC process is the only effective way to meet this challenge, but today the unavailability of detailed information about process tool margins is preventing true DFM of process technology from becoming a reality. Statistical metrology is a method consisting of a short‐loop process flows and parametric electrical test that can supply the margin performance data of specific process tools needed for DFM. Test structures are designed with large numbers of test sites and with a variety of sensitivities to the process variations. Each structure uses the minimum tool set and process flow necessary for electrically measurable parameters so as to ease the inversion of statistically confounded data. By utilizing technology computer‐aided design (TCAD) tools to simulate the short process flow and by assigning statistical distributions to individual steps, a best fit to the data provides useful calibration data of key TCAD parameters. These parameters can then be used to simulate the process margin of a full process and, through DFM, make the process optimally robust for manufacturing.

ISSN:1071-1023    

DOI:10.1116/1.587192

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

In order to maintain an effective and competitive manufacturing environment in the microelectronic industry, continual improvement to the fabrication tools is mandated. One of the myriad of measurement philosophies available is the concept of overall equipment effectiveness (OEE), which is a part of total productive maintenance (TPM). Results of an 18 month study on improving the OEE of single wafer aluminum plasma etchers are presented. At the start of the project, several designed experiments were performed to optimize the plasma etch process. A detailed logging procedure was implemented that accounted for the various equipment operating states as well as the number of wafers processed. The OEE for the initial 6 months of the program was determined to have an average value of 42%. Improvements to the etchers, their operation and maintenance were implemented as a result of the TPM program. During the last 4 months of the study, the average value for OEE was 67%, an increase of 60%.  

ISSN:1071-1023    

DOI:10.1116/1.587193

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

A gate technology for producing 0.1‐μm gate length silicon complementary metal–oxide– semiconductor (CMOS) circuits has been developed by integratingg‐line exposure, resist narrowing, deep UV hardening, and dry etching of nitride and polysilicon. The 0.1‐μm gate lengthn‐channel andp‐channel MOS devices have been previously processed via e‐beam lithography using a chemically amplified e‐beam resist. However, the e‐beam technique suffers from low throughput, especially in processing complex circuits. In addition, the chemically amplified e‐beam resist requires prompt processing. Thusg‐line exposure and photoresist narrowing was chosen as an alternative. The resist features were narrowed from 0.5 μm down to 0.1 μm using low power O2plasma. The profile of the narrowed resist shows that the body is thicker than the base. The narrowed resist features were then hardened by deep UV in order for the photoresist to withstand the subsequent nitride etch using CHF3reactive ion etching (RIE). The obtained nitride profile shows a rounded top which is expected from the profile of resist features. The subsequent polysilicon etch was done using a two‐step Cl2RIE. The obtained profile of polysilicon is comparable to that previously obtained using e‐beam lithography. This gate technology was used to successfully fabricate 0.1‐μm circuits such as conventional unloaded CMOS ring oscillators and 2:1 frequency dividers.

ISSN:1071-1023    

DOI:10.1116/1.587194

出版商:American Vacuum Society    

年代:1994

数据来源: AIP

摘要:

Actual power delivered to the discharge, rf voltage, rf current, phase angle, and dc bias have been measured using commercially available impedance and power meters placed directly on the powered electrode of a parallel‐plate diode etcher. The variation of these electrical quantities as discharge parameters such as power, pressure, electrode spacing, gas mixing ratio, and total flow are varied has been investigated for both electropositive and electronegative gases. It was found that the transfer efficiency of the matching network depends significantly on the process conditions and can be as low as 55% of the generator output. Polysilicon etch rate experiments were performed to determine the effect of varying the actual power delivered to the discharge and possible interaction with other process parameters such as pressure, as opposed to considering solely the rf generator output. End point was detected by measuring the change in the discharge impedance while etching through a polysilicon film. The sensitivity of this technique was compared with that of more commonly used optical emission methods.

ISSN:1071-1023    

DOI:10.1116/1.587195

出版商:American Vacuum Society    

年代:1994

数据来源: AIP