Apparatus and method for detection and measurement of environmental parameters

Abstract

The present invention provides a device for in-situ measurement and recording of various environmental parameters in a semiconductor fabrication process. The device comprises sensors for detecting the parameters and converting them to sensor outputs; and a data logger coupled to the sensors for receiving the sensor outputs and logging them in a file. The device may also comprise an analog to digital converter to convert the sensor outputs to digital data and a communication module to communicate the digital data with other devices. When applied to reticles used in a semiconductor fabrication process comprising a plurality of stages, the device may be used to monitor electrostatic field and electrostatic discharge activities on and around the reticle, convert the monitored parameters into data, and log the data along with a timestamp and an identification of each individual stage. Logged data can be retrieved and analyzed to determine the time and location of detrimental activities such as electrostatic discharge on reticles.

1 . A device for in-situ measurement and recording of at least one parameter in a process, said device comprising: 
 a sensor for detecting said parameter and converting to a sensor output; and    a data logger coupled to said sensor for receiving and logging said sensor output.    
     
     
         2 . The device of  claim 1  wherein said data logger comprises a timestamping module for recording a timestamp with said sensor output.  
     
     
         3 . The device of  claim 2  further comprising a communication module for communicating said sensor output.  
     
     
         4 . The device of  claim 3  wherein said communication module comprises a transmitter and a receiver.  
     
     
         5 . The device of  claim 3  wherein said communication module comprises an RF (radio frequency) communication module.  
     
     
         6 . The device of  claim 1  further comprising a display device.  
     
     
         7 . The device of  claim 1  wherein said sensor is configured to detect a presence of electrostatic field.  
     
     
         8 . The device of  claim 7  wherein said sensor is configured to measure a magnitude of said electrostatic field.  
     
     
         9 . The device of  claim 8  wherein said sensor is configured to detect a change in said electrostatic field.  
     
     
         10 . The device of  claim 1  wherein said sensor is configured to detect an electrostatic discharge.  
     
     
         11 . The device of  claim 10  wherein said sensor is configured to measure a magnitude of said electrostatic discharge.  
     
     
         12 . The device of  claim 1  wherein said data logger comprises an analog to digital converter (ADC) to convert said sensor output into digital data.  
     
     
         13 . The device of  claim 12  further comprising signal processing circuitry coupled to said sensor for processing said sensor output.  
     
     
         14 . A device for in-situ measurement and recording of at least one parameter in a process, said device comprising: 
 means for detecting said parameter and converting to a sensor output; and    means for receiving and logging said sensor output.    
     
     
         15 . The device of  claim 14  wherein said means for receiving and logging comprises a timestamping module for recording a timestamp with said sensor output.  
     
     
         16 . The device of  claim 13  further comprising means for communicating said sensor output.  
     
     
         17 . The device of  claim 16  wherein said means for communicating comprises a transmitter and a receiver.  
     
     
         18 . The device of  claim 16  wherein said means for communicating comprises an RF (radio frequency) communication module.  
     
     
         19 . A method for in-situ measurement and recording of at least one parameter in a semiconductor fabrication process comprising a plurality of stages, said method comprising: 
 (a) monitoring said parameter in a stage of said plurality of stages;    (b) converting said parameter into data;    (c) logging said data and an identification of said stage; and    (d) repeating (a)-(d) for said plurality of stages.    
     
     
         20 . The method of  claim 19  further comprising timestamping said data.  
     
     
         21 . The method of  claim 20  further comprising signal processing said data.  
     
     
         22 . The method of  claim 21  further comprising converting said data into digital data.  
     
     
         23 . The method of  claim 22  further comprising communicating said digital data and said identification of said stage to a base equipment.  
     
     
         24 . The method of  claim 23  wherein said parameter comprises electrostatic field.  
     
     
         25 . The method of  claim 24  wherein said parameter comprises a change in said electrostatic field.  
     
     
         26 . The method of  claim 25  wherein said parameter comprises an electrostatic discharge.  
     
     
         27 . The method of  claim 26  further comprising eliminating extraneous electrostatic discharges based on said electrostatic discharge and said electrostatic field.  
     
     
         28 . A device for in-situ monitoring of at least one environmental parameter in a photolithographic process comprising a plurality of stages, said device comprising: 
 at least one sensor for converting said environmental parameter of an associated stage into a sensor output;    an analog to digital converter for converting said sensor output to digital data; and    a communication module to communicate said digital data and an identification of said associated stage of said plurality of stages.    
     
     
         29 . The device of  claim 28  further comprising a data logger for logging said digital data and said identification of said associated stage.  
     
     
         30 . The device of  claim 29  wherein said communication module comprises a transmitter and a receiver.  
     
     
         31 . The device of  claim 29  wherein said communication module comprises an RF (radio frequency) communication module.  
     
     
         32 . The device of  claim 28  further comprising a display device.  
     
     
         33 . The device of  claim 28  further comprising a sensor for detecting a presence of electrostatic field.  
     
     
         34 . The device of  claim 33  wherein said sensor is configured to measure a magnitude of said electrostatic field.  
     
     
         35 . The device of  claim 34  wherein said sensor is configured to detect a change in said electrostatic field.  
     
     
         36 . The device of  claim 28  further comprising a sensor for detecting an electrostatic discharge.  
     
     
         37 . The device of  claim 36  wherein said sensor is configured to measure a magnitude of said electrostatic discharge.  
     
     
         38 . The device of  claim 28  further comprising signal processing circuitry coupled to said plurality of sensors for processing said sensor output.  
     
     
         39 . A device for use in conjunction with a reticle for in-situ monitoring of at least one electrical parameter in a semiconductor fabrication process comprising a plurality of stages, said device comprising: 
 a sensor for converting said electrical parameter of a stage into a sensor output;    an analog to digital converter for converting said sensor output to digital data;    a data logger comprising a timestamping module for logging said digital data and an identification of said stage; and    an RF (radio frequency) communication module coupled to said data logger.    
     
     
         40 . The device of  claim 39  wherein said electrical parameter comprises electrostatic field.  
     
     
         41 . The device of  claim 39  wherein electrical parameter comprises an electrostatic discharge.  
     
     
         42 . A method for in-situ measurement and recording of at least one parameter in a semiconductor fabrication process comprising at least one stage, said method comprising: 
 (a) monitoring said parameter in said stage;    (b) converting said parameter into data; and    (c) logging said data and an identification of said stage.    
     
     
         43 . The method of  claim 42  further comprising 
 timestamping said data.  
 
     
     
         44 . The method of  claim 43  further comprising: 
 signal processing said data.  
 
     
     
         45 . The method of  claim 44  further comprising: 
 converting said data into digital data.  
 
     
     
         46 . The method of  claim 44  further comprising: 
 communicating said digital data and said identification of said stage to a base equipment.  
 
     
     
         47 . The method of  claim 46  wherein said parameter comprises electrostatic field.  
     
     
         48 . The method of  claim 46  wherein said parameter comprises an electrostatic discharge.  
     
     
         49 . A device for monitoring environmental parameters comprising: 
 an electrostatic sensor for detecting electrostatic field and converting said electrostatic field into a first output;    an electrostatic discharge (ESD) sensor for detecting an electrostatic discharge and converting said electrostatic discharge into a second sensor output;    an analog to digital converter coupled to said electrostatic sensor and said ESD sensor for converting said first and second sensor outputs to first and second digital data, respectively; and    a data logger comprising a timestamping module for logging said first and second digital data.    
     
     
         50 . The device of  claim 49  further comprising an RF (radio frequency) communication module coupled to said data logger.  
     
     
         51 . A method for localizing electrostatic discharges (ESD) by detecting electrostatic discharges and electrostatic field, the method comprising: 
 detecting an electrostatic discharge and converting it into a first output;    detecting said electrostatic field and converting it into a second output; and    determining a valid local electrostatic discharge based on said first and second outputs.    
     
     
         52 . The method of  claim 51  wherein said determining comprises determining said valid local electrostatic discharge when said electrostatic discharge is combined with said electrostatic field having a magnitude that exceeds a predetermined value.  
     
     
         53 . The method of  claim 52  further comprising converting said first and second outputs to first and second digital data, respectively.  
     
     
         54 . A device for localizing electrostatic discharges affecting a unit by detecting an electrostatic discharge and electrostatic field, the device comprising: 
 an electrostatic sensor for detecting said electrostatic field affecting said unit and generating a first output; and    an ESD sensor for detecting said electrostatic discharge affecting said unit and generating a second output.    
     
     
         55 . The device of  claim 54  further comprising: 
 an analog comparator coupled to said first output for generating a comparator output when said electrostatic field has a magnitude exceeding a predetermined value.  
 
     
     
         56 . The device of  claim 55  further comprising: 
 a circuit coupled to said analog comparator and to said ESD sensor for receiving said comparator output and said second output, said circuit configured to generate a valid ESD signal when said comparator output and said second output are detected.  
 
     
     
         57 . The device of  claim 54  further comprising: 
 an analog to digital converter (ADC) coupled to said electrostatic sensor and said ESD sensor for converting said first and second outputs to first and second digital data, respectively.  
 
     
     
         58 . The device of  claim 57  further comprising: 
 a digital comparator coupled to said first data and generating a comparator output when said electrostatic field has a magnitude exceeding a predetermined value.  
 
     
     
         59 . The device of  claim 58  further comprising: 
 a circuit coupled to said digital comparator and to said ADC for receiving said comparator output and said second data, said circuit configured to generate a valid ESD signal when said comparator output and said second data are detected.  
 
     
     
         60 . The device of  claim 59  wherein said circuit is an AND gate.  
     
     
         61 . The device of  claim 60  further comprising: 
 a data logger comprising a timestamping module for logging said first and second digital data.  
 
     
     
         62 . The device of  claim 61  further comprising an RF (radio frequency) communication module coupled to said data logger.  
     
     
         63 . A method for localizing electrostatic discharges (ESD) by detecting electrostatic discharges and electrostatic field, the method comprising: 
 detecting an electrostatic discharge and converting it into a first output;    detecting a change in said electrostatic field and converting it into a second output; and    determining a valid local electrostatic discharge based on said first and second outputs.    
     
     
         64 . The method of  claim 63  wherein said determining comprises determining said valid local electrostatic discharge when said electrostatic discharge is combined with said electrostatic field changing at a rate that exceeds a predetermined value.  
     
     
         65 . The method of  claim 64  further comprising converting said first and second outputs to first and second digital data, respectively.  
     
     
         66 . A device for localizing electrostatic discharges affecting a unit by detecting an electrostatic discharge and electrostatic field; 
 an electrostatic sensor for detecting a change in said electrostatic field and generating a first output; and    an ESD sensor for detecting said electrostatic discharge and generating a second output.    
     
     
         67 . The device of  claim 66  further comprising: 
 a high pass filter coupled to said first output for generating a high pass filter output when said electrostatic field changes at a rate exceeding a predetermined value.  
 
     
     
         68 . The device of  claim 67  further comprising: 
 a circuit coupled to said high pass filter and to said ESD sensor for receiving said high pass filter output and said second output, said circuit configured to generate a valid ESD signal when said high pass filter output and said second output are detected.  
 
     
     
         69 . The device of  claim 68  further comprising: 
 an analog to digital converter (ADC) coupled to said electrostatic sensor and said ESD sensor for converting said first and second outputs to first and second digital data, respectively.  
 
     
     
         70 . The device of  claim 69  further comprising: 
 a high pass filter coupled to said first data for generating a high pass filter output when said electrostatic field changes at a rate exceeding a predetermined value.  
 
     
     
         71 . The device of  claim 70  wherein said high pass filter comprises software codes executable by a microprocessor.  
     
     
         72 . The device of  claim 70  further comprising: 
 a circuit coupled to said high pass filter and to said ADC for receiving said high pass filter output and said second data, said circuit configured to generate a valid ESD signal when said high pass filter output and said second data are detected.  
 
     
     
         73 . The device of  claim 72  wherein said circuit is an AND gate.  
     
     
         74 . The device of  claim 73  further comprising: 
 a data logger comprising a timestamping module for logging said first and second digital data.  
 
     
     
         75 . The device of  claim 74  further comprising an RF (radio frequency) communication module coupled to said data logger.