In situ mass spectrometry in a 10 Torr W chemical vapor deposition process for film thickness metrology and real-time advanced process control

Abstract

Articles you may be interested inIn situ chemical sensing in Al Ga N ∕ Ga N metal organic chemical vapor deposition process for precision film thickness metrology and real-time advanced process control J. Vac. Sci. Technol. B 23, 2007 (2005; 10.1116/1.2037707Real-time, in situ film thickness metrology in a 10 Torr W chemical vapor deposition process using an acoustic sensor J.Thickness metrology and end point control in W chemical vapor deposition process from SiH 4 / WF 6 using in situ mass spectrometry Process diagnostics and thickness metrology using in situ mass spectrometry for the chemical vapor deposition of W from H 2 / WF 6In situ mass spectrometric sensing has been implemented in a 10 Torr H 2 /WF 6 W chemical vapor deposition process as a real-time process and wafer state metrology tool. Dynamic sensing through the process cycle reveals HF byproduct generation as well as H 2 and WF 6 reactant depletion as real-time quantitative indicators of deposition on the wafer. Thickness metrology is achieved by integrating the HF byproduct signal through the process cycle and comparing it to post-process measurements of film weight. To evaluate the quantitative precision of this metrology, multiwafer runs have been performed under different sets of conditions: ͑1͒ fixed process conditions, ͑2͒ intentionally introduced run-to-run process temperature drift, and ͑3͒ run-to-run deposition time variation. These results demonstrate that real-time thickness metrology is achievable at a level of 1% or better in two application settings: ͑1͒ when an essentially fixed process recipe is employed, as in high-volume manufacturing; and ͑2͒ when more substantial changes in process recipe are explored, as in a development environment. In situ mass spectrometry presents an attractive option for real-time advanced process control with the prognosis for real-time course correction demonstrated here and its already established benefit to fault detection and classification.

In situ chemical sensing in AlGaN∕GaN high electron mobility transistor metalorganic chemical vapor deposition process for real-time prediction of product crystal quality and advanced process control

“…Because methane and ethane are clearly the byproducts of the growth reaction of our interest, it is expected that they contain the wafer-state information indicative of deposition on the wafer, as well as the process-state information normally expected. It has already been clearly demonstrated in the past that these kinds of in situ sensor-based signals do indeed correlate to the wafer state in real time, in some cases with high quantitative precision that allows precision metrology 46 and subsequent control 43 of the wafer state ͑e.g., film thickness deposited͒. Moreover, in this case, assuming that each of the two byproducts come from different reaction pathways to grow the GaN-based material on the wafer ͑see Fig.…”

“…[4][5][6] Our research group at the University of Maryland has been an active contributor in these various aspects of APC, especially in the use of in situ chemical sensors to drive real-time wafer-state metrology and control in Si ULSI processes. [36][37][38][39][40][41][42][43][44][45][46] Understanding the relevant challenges currently facing the development of GaN-based processes for manufacturing in electronic applications, we have applied similar APC approaches in hopes of achieving manufacturing reproducibility and increased understanding of the process chemistry. [47][48][49][50][51][52] We have employed in situ mass spectrometry for real-time process sensing during the GaN MOCVD process, initially devoted to numerous FDC applications and subsequently to quantitative metrologies for predicting material quality, film thickness, etc.…”

Real-time material quality prediction, fault detection, and contamination control in AlGaN∕GaN high electron mobility transistor metalorganic chemical vapor deposition process using in situ chemical sensing

“…4,5 Our research group has been an active contributor in various aspects of APC, especially in the use of real-time in situ chemical sensors for both FDC and course correction. [6][7][8][9][10][11][12][13][14][15][16] In view of the relevant challenges currently facing the development of GaN-based processes for manufacturing in electronic applications, we have applied similar APC approaches based on our past experience in Si-based processes in hopes of achieving process reproducibility sufficient for manufacturing. 17,18 We have employed in situ mass spectrometry in AlGaN / GaN / AlN metalorganic chemical vapor deposition ͑MOCVD͒ processes to grow high electron mobility transistor ͑HEMT͒ heterostructures on semi-insulating SiC for high frequency/power electronic devices.…”

In-Situ Metrology: the Path to Real-Time Advanced Process Control

“…At higher pressures (10 torr) the quality of the thickness metrology is even better, which is important because W CVD processes in manufacturing operate at 100-500 torr. [36] Using the HF product signal from the H 2 reduction reaction, a linear regression fit to the weight (thickness) vs. integrated HF product signal yielded a standard deviation of 0.67% uncertainty, as indicated in Fig. 4.…”

“…For example, RTCVD poly Si and oxide results showed generation of reaction products and depletion of reactants to an extent dependent on reaction rate, and they indicated the possibility of using these for deposition rate metrology [34] . More recently, we have evaluated the metrology accuracy obtainable using downstream mass spec for several W CVD processes, both H 2 reduction [35,36] and SiH 4 reduction [37], as carried out in a Ulvac ERA-1000 W CVD cluster tool. With reasonable reactant conversion rates (-20%) in the SiH4 reduction process, thickness metrology of 1-1.5% accuracy was demonstrated and exploited to achieve real-time end point control consistent with this metrology.…”