ABSTRACT
To reduced it faulty period in semiconductor development procedure, a novel indicator fault recognition in a plasma etching system program using a Broadband RF sensor was designed. The work presented here concentrates on discovering mistakes in the TCP statistic and stress indicator, though the technique has potential for several of the other receptors. To improve the recognition understanding, we used real-time device feedback evaluation, and in comparison it from real recipe establishing instead of using raw RF alerts directly. For a primary imprinted procedure on a Lam TCP 9400SE , 10 % relative diversions in TCP statistic, or 25 % in stress replicating specific TCP and stress indicator mistakes in scribing procedure can be recognized with high accuracy: Detection possibility PD 1 and false alarm amount PF 0 for both.
Introduction
As described by Bogardus mistake recognition studies in semiconductor development are motivated by the needs to decrease 1) devices recovery time by rapid identi
cation and depiction of a mistake, 2) the variety of discarded wafers by determining when the devices is not managing properly, and 3) the variety of analyze wafers by determining optimum devices managing circumstances. Breakdown should be prevented by means of preventive servicing or, at least, be recognized and retrieved from as soon as possible to minimize device recovery time and loss of wafers. Machine malfunction brought on by mechanical subsystem failure, such as a broken wafer transfer robot arm, is easy to identify via visual inspection. However, indicator mistakes brought on by indicator aging, miscalibration, or flow are threatening and cannot be easily recognized until scheduled servicing or post-process wafer quality check. With the decrease in device function dimension and increase in wafer dimension, a tight control of the procedure is crucial. This requires more restrictive procedure mistake and flow edge. Thus, even minor mistakes in receptors can signi
cantly impact the procedure result. To decrease COO, mistakes in receptors should be recognized quickly and repaired as soon as possible. Various mistake recognition and classi
cation techniques have been used in semiconductor development areas: photolithography [2], Plasma tv's Enhanced Substance Steam Deposit (PECVD) [3], Low Pressure Substance Steam Deposit (LPCVD) [4], and lcd imprinted [5{9]. For example, devices models to identify devices does not work effectively at a given procedure phase were designed and used to identify mistakes in the PECVD nitride procedure [3]. For the identi
cation of gas ow operator does not work effectively in the Sensitive Ion Etching (RIE) program, sensory network trained on the supervised data using a feed-forward, mistake back-propagation criteria was used [7, 9]. An expert program that automatically translates the records was also designed and tested on the lcd imprinted procedure [5]. In this paper, we propose a new strategy of indicator mistake recognition depending on High speed internet Radio Regularity (BRF) indicator indication statement. Speci
cally, we used this RF indicator centered mistake recognition to the RIE program to identify procedure problem brought on by indicator mistake quickly. By tracking the wide variety of lcd impedance difference, the High speed internet RF indicator enables us to determine the real resource of the problem. For mistake recognition, the scribing procedure was selected since it is a essential and permanent phase in chip development. Therefore, accurate and timely recognition of indicator mistakes in this area is crucial to the reduction of development cost. We also employed a non-parametric sign analyze to decide the event of indicator mistake via High speed internet RF indicator indication statement. The non-parametric recognition technique is a useful and e
ective technique when the possibility density func-3 tion (pdf ) of the detectors feedback is unknown [10]. The non-parametric recognition technique provides constant performance regardless of the real pdf. We utilized the High speed internet RF sensor's unique attribute to identify procedure problems brought on by indicator mistake quickly, and furthermore, determine the resource of the problem by tracking the wide variety of lcd impedance. Plasma tv's impedance contains important info about lcd features such as ion concentration (resistance) and sheath width (reactance), which are factors crucial to the imprinted amount and imprinted pro
le. The lcd impedance is strongly dependent on the speci
c lcd generation factors such as stress, supplied energy, gas ow amount, and stage circumstances. A variety of researchers have examined lcd impedance. Maynard et al. used RF metrology for the endpoint recognition of the scribing procedure depending on the modify of impedance when a new
lm layer was exposed to the lcd [11]. Scanlan used the lcd impedance and ion ux tracking to study lcd flow and ion ux consistency [12]. Garvin at the University of Mich followed a new High speed internet RF realizing strategy [13]. The traditional RF realizing strategy only measures the impedance of the essential frequency (typically 13.56 MHz), which is how often of the Changing Current (AC) energy used to generate the lcd, or couples of harmonic wavelengths at most [14]. The unique function of Garvin's High speed internet RF realizing strategy includes that it tests a wide frequency variety, generally 1 2 GHz, and examines the gathered RF indication as a whole. Thus, a small difference of lcd circumstances can be recognized, which is impossible by traditional RF indicator statistic. Figure 1 features the comparison of the re ectance coeÆcient in scale vs. frequency between an vacant stage (no process) and a stage under the poly-Si Main Etch (ME). Two resounding mountains appear in the variety of 1 1.5 GHz under the ME of poly-Si whereas rather noisy mountains in 2 2.5 GHz. In the indicator mistake recognition try things out, we assume the following conditions: A. The RF indicator is more reliable and solid than the other receptors in the lcd scribing program. B. Only one indicator can fail at once. C. Sensor problem can be simulated by a modify in it feedback establishing. Its simple con
guration and lack of moving parts make the High speed internet RF indicator more solid as opposed to other receptors in the lcd scribing program. Because the prospect of multiple event of mistakes in two or more receptors is extremely low, we have chosen to ignore this scenario as an trial condition. Moreover, instead of miscalibrating or tampering with the indicator, we deliberately modified it feedback establishing to create indicator mistake. For example, if the pressure4 indicator is not working, then the real stage stress would be di
erent from the affordable stress due to the . Hence, we modified the stress establishing from its affordable value to imitate a stress indicator mistake. Area II reviews the fundamentals of recognition theory, and then Area III is followed by a brief description of the trial installation. The Design of Experiment (DOE) to extract the unique RF indicator indication
ngerprints under the indicator mistake event is explained in Area IV. Area V talks about the trial results of the TCP and stress indicator mistake recognition program. We determine with a summary in Area VI.