Process diagnostics and thickness metrology using in situ mass spectrometry for the chemical vapor deposition of W from H2/WF6

Abstract

Thickness metrology and end point control in W chemical vapor deposition process from SiH 4 / WF 6 using in situ mass spectrometry Process sensing and metrology in gate oxide growth by rapid thermal chemical vapor deposition from SiH 4 and N 2 O Quadrupole mass spectrometry has been used to monitor reactant and product partial pressures in a selective W chemical vapor deposition process. A 4/1H 2 /WF 6 molar reactant ratio was used to produce W films on Si wafers, at 67 Pa ͑0.5 Torr͒ total pressure, and for wafer temperatures around 400°C. A relatively fast response time ͑ϳ4 s͒ sensor system sampled gas directly from a commercial Ulvac ERA-1000 reactor in order to minimize the effect of wall reactions. The signal from the volatile HF product, integrated over the deposition cycle, and corrected for contributions from reactions in the ion-source region of the quadrupole and for sensor drifts, was found to vary linearly with the weight of the W film deposited, to within an uncertainty of ϳ7%. This provides the basis for real-time, noninvasive thickness metrology to drive process control. Depletion of both H 2 and WF 6 reactants was observed. The time integral of the H 2 reactant depletion was also linearly related to the film weight, though the data exhibited a somewhat larger scatter due to the low conversion efficiency of the process. In addition, volatile SiF 4 and SiHF 3 products of the initial rapid W nucleation reaction on the Si surface were clearly observed, indicating that initial surface conditions may be monitored in real time under selective growth conditions.

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

“…[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.…”

In Situ Selectivity and Thickness Monitoring During Selective Silicon Epitaxy Using Quadrupole Mass Spectrometry and Wavelets

“…Some recent real-time applications of QMS include: in situ feedback control of a plasma enhanced chemical-vapor deposition (PECVD) process (Knight [3] and Greve et al [4]), sidewall spacer etching (Min [5]), endpoint uniformity sensing and analysis during silicon dioxide plasma etching (Chambers et al, [6], [7]), monitoring of a tungsten metal CVD process (Kobayashi et al [8]), process sensing and metrology in amorphous and selective area silicon plasma deposition (Chowdhury et al [9]), process sensing during rapid thermal chemical-vapor deposition (RTCVD) of polysilicon (Rying et al [10], Tedder [11], [12], Smith [13], Lu [14], [15], and Rubloff et al [16]), and more recently in situ monitoring and characterization of RTCVD thin oxide (SiO ), nitride (Si N ), and tungsten (W) films (Lu et al [17], Rying et al [18], and Gougousi et al [19], [20]). …”

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.…”