Non-destructive semiconductor wafer probing system using laser pulses to generate and detect millimeter wave signals

• US 5,142,224 A
• Filed: 04/26/1991
• Issued: 08/25/1992
• Est. Priority Date: 12/13/1988
• Status: Expired due to Term

• Current Assignee: MACOM Technology Solutions Holdings, Inc.
• Original Assignee: COMSAT Corporation (Reorganized ISA SA)
• Inventors: Lee, Chi Hsiang, Smith, Thane, Huang, Ho-Chung
• Primary Examiner(s): Karlsen, Ernest F.
• Application Number:
  US07/690,329
• Time in Patent Office: 487 Days
• Field of Search: 324/158 R, 324/158 D, 324/158 T, 324/96, 324/73.1
• US Class Current: 324/754.23
• CPC Class Codes: G01R 31/308 using non-ionising electromagnetic radiation, e.g. optical radiation investigating or analysing materials by the use of optical means G01N21/00; image analysis G06T7/00

Abstract

Electrical devices are characterized by optically triggering an electrical signal onto the device and then optically sampling the electrical signal waveform on the device.

Claims

1. A system for testing a plurality of electrical devices each having an input side and an output side, said electrical devices being fabricated on a semiconductor wafer with areas of said wafer disposed between adjacent devices for cutting said devices from one another, said system comprising:

first means for generating at least first and second optical pulses;

second means responsive to said first optical pulse for generating an electrical signal at said input side of said device;

third means responsive to said second optical pulse for sampling an electrical signal at at least a first location which comprises one of said input and output sides of said device; and

processing means for processing at least the electrical signal sampled by said third means to characterize said electrical device,

wherein at least portions of said first, second and third means are formed in said areas of said semiconductor wafer, which will be cut from said device when dicing said wafer, and

wherein said first means generates a third optical pulse, said system further including fourth means responsive to said third optical pulse for sampling said electrical signal at a second location which comprises the other of said input and output sides of said device.

2. A system for testing a plurality of electrical devices each having an input side and an output side, said electrical devices being fabricated on a semiconductor wafer with ares of said wafer disposed between adjacent devices for cutting said devices from one another, said system comprising:

first means for generating at least first and second optical pulses;

second means responsive to said first optical pulse for generating an electrical signal at said input side of said device;

third means responsive to said second optical pulse for sampling an electrical signal at at least a first location which comprises one of said input and output sides of said device; and

processing means for processing at least the electrical signal sampled by said third means to characterize said electrical device,

wherein at least portions of said first, second and third means are formed in said areas of said semiconductor wafer, which will be cut from said device when dicing said wafer, and

wherein said second means comprises a first transmission line section, a bias source and means for coupling said bias source to said first transmission line section across a first photoconductive gap, and means for directing said first optical pulse to said photoconductive gap.

3. A system according to claim 2, wherein said third means comprises a second transmission line section and a first sampling capacitor coupled to said second transmission line section across a second photoconductive gap, and means for directing said second optical pulse to said second photoconductive gap.

4. A system according to claim 2, wherein said third means comprises a first sampling capacitor coupled to said first transmission line section across a second photoconductive gap, and means for directing said second optical pulse to said second photoconductive gap.

5. A system for testing an electrical device having an input side and an output side, said electrical device being fabricated on a semiconductor wafer, said system comprising:

first means for generating at least first and second optical pulses;

second means responsive to said first optical pulse for generating an electrical signal at said input side of said device;

third means responsive to said second optical pulse for sampling an electrical signal at at least a first location which comprises one of said input and output sides of said device, said third means comprising means for receiving said second optical pulse after reflection thereof from said device, and means for analyzing the polarization of the reflected pulse; and

processing means for processing at least the electrical signal sampled by said third means to characterize said electrical device.

6. A system according to claim 5, wherein said first means comprises means for generating a laser pulse and means for deriving said first and second optical pulses from said laser pulse, at least one of said first and second optical pulses having a wavelength shorter than that of said laser pulse.

7. A system according to claim 5, wherein said first optical pulse has a wavelength shorter than that of said laser optical pulse.

8. A system according to claim 6, wherein said first optical pulse has a wavelength shorter than that of said laser optical pulse.

9. A system for testing an electrical device having an input side and an output side, said electrical device being fabricated on a semiconductor wafer, said system comprising:

first means for generating at least first and second optical pulses, said first means comprising a pulse laser for generating a laser pulse, optical means for passing said laser pulse along a primary optical path, beam splitting means for obtaining a plurality of secondary pulses from said laser pulse, and means for providing two of said secondary pulses as said first and second optical pulses, at least one of said first and second optical pulses having a wavelength shorter than a wavelength of said laser pulse;

second means responsive to said first optical pulse for generating an electrical signal at said input side of said device;

third means responsive to said second optical pulse for sampling an electrical signal at at least a first location which comprises one of said input and output sides of said device; and

processing means for processing at least the electrical signal sampled by said third means for to characterize said electrical device.

10. A system according to claim 9, further comprising variable delay means disposed in the optical path of the secondary pulse for delaying the respective pulse by a desired amount.

11. A system according to claim 10, wherein said variable delay means comprises a path length adjustment means.

12. A system for testing an electrical device having an input side and an output side, said electrical device being fabricated on a semiconductor wafer, said system comprising:

first means for generating at least first and second optical pulses, said first means comprising a pulse laser for generating a laser pulse, optical means for passing said laser pulse along a primary optical path, beam splitting means for obtaining a plurality of secondary pulses from said laser pulse, a convex lens for receiving said two secondary pulses as parallel optical pulses with a first relatively wide spacing and for converging said two optical pulses toward one another in a direction toward said device, and a concave lens for receiving the converging optical pulses and for providing as an output said two optical pulses at a second spacing narrower than said first spacing;

second means responsive to said first optical pulse for generating an electrical signal at said input side of said device;

third means responsive to said second optical pulse for sampling an electrical signal at at least a first location which comprises one of said input and output sides of said device; and

processing means for processing at least the electrical signal sampled by said third means to characterize said electrical device.

13. A system for testing a plurality of electrical devices each having an input side and an output side, said electrical devices being fabricated on a semiconductor wafer with areas of said wafer disposed between adjacent devices for cutting said devices from one another, said system comprising:

first means for generating at least first and second optical pulses;

second means responsive to said first optical pulse for generating an electrical signal at said input side of said device;

third means responsive to said second optical pulse for sampling an electrical signal at at least a first location which comprises one of said input and output sides of said device; and

processing means for processing at least the electrical signal sampled by said third means to characterize said electrical device,

wherein at least portions of said first, second and third means are formed in said areas of said semiconductor wafer, which will be cut from said device when dicing said wafer, and

wherein said processing means is responsive to a plurality of sampled electrical signals from said third means for calculating a Fourier transform of a time domain waveform represented by said plurality of sampled electrical signals to obtain a frequency domain waveform for characterizing said device.

14. A system for testing an electrical device having an input side and an output side, said electrical device being fabricated on a semiconductor wafer, said system comprising:

first means for generating at least first and second optical pulses, said first means comprising a pulse laser for generating a laser pulse, optical means for passing said laser pulse along a primary optical path, beam splitting means for obtaining a plurality of secondary pulses from said laser pulse, and means for providing two of said secondary pulses as said first and second optical pulses, said means for providing comprising a convex lens for receiving said two secondary pulses as parallel optical pulses with a first relatively wide spacing and for converging said two optical pulses toward one another in a direction toward said device, and a concave lens for receiving the converging optical pulses and for providing as an output said two optical pulses at a second spacing narrower than said first spacing;

second means responsive to said first optical pulse for generating an electrical signal at said input side of said device;

third means responsive to said second optical pulse for sampling an electrical signal at at least a first location which comprises one of said input and output sides of said device; and

processing means for processing at least the electrical signal sampled by said third means for to characterize said electrical device.