Method and apparatus for determining endpoint of semiconductor element fabricating process

• US 6,903,826 B2
• Filed: 09/06/2001
• Issued: 06/07/2005
• Est. Priority Date: 09/06/2001
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Fujii, Takashi, Yoshigai, Motohiko, Usui, Tatehito, Yamamoto, Hideyuki, Kaji, Tetsunori
• Primary Examiner(s): Turner, Samuel A.
• Assistant Examiner(s): Lyons, Michael A.
• Application Number:
  US09/946,504
• Publication Number:
  US 20030043383A1
• Time in Patent Office: 1,370 Days
• Field of Search: 356/451, 356/503, 356/504
• US Class Current: 356/504
• CPC Class Codes: G01B 11/0675 using interferometry
• CPC Class Codes: H01J 37/32963 End-point detection
• CPC Class Codes: H01L 22/26 Acting in response to an ongoing measurement without interruption of processing, e.g. endpoint detection, in-situ thickness measurement endpoint detection arrangements in CMP apparatus B24B37/013, in discharge apparatus H01J37/32

Abstract

Standard patterns of differential values of interference light that correspond to a predetermined step height of the first material being processed and standard patterns of differential values of interference light that correspond to a predetermined remaining mask layer thickness of the material are set. These standard patterns use wavelengths as parameters. Then, the intensities of interference light of multiple wavelengths are measured for a second material that has the same structure as the first material. Actual patterns with wavelength as parameter are determined from differential values of the measured interference light intensities. Based on the standard patterns and the actual patterns of the differential values, the step height and the remaining mask layer thickness of the second material are determined.

Claims

1. A method of measuring a film process quantity in a semiconductor device manufacturing process, comprising:

a) setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed that corresponds to a predetermined film process quantity of the first material;

b) measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths; and

c) determining a film process quantity of the second material based on the standard pattern consisting of the time differential values and the actual pattern consisting of the time differential values.

2. A method of measuring a film process quantity in a semiconductor device manufacturing process according to claim 1, comprising:

performing processing by changing a process condition when the film process quantity of the second material reaches a predetermined value.

3. A method of measuring an etch quantity of a material being processed, comprising:

a) setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed that corresponds to a predetermined etch quantity of the first material including a mask layer;

b) setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from the mask layer of the first material that correspond to a predetermined etch quantity of the mask layer;

c) measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths; and

d) determining an etch quantity of the second material based on the standard pattern of the first material, the standard pattern of the mask layer, and the actual of the second material.

4. A method of measuring an etch quantity of a material being processed, comprising:

a) setting a standard patterns, each consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed, that correspond to a plurality of predetermined etch quantities of the first material including a mask layer, the respectively;

b) setting a standard patterns, each consisting of a time differential value of an interference light intensity for each of multiple wavelengths from the mask layer of the first material, that correspond to a plurality of predetermined etch quantities of the mask layer, respectively;

c) measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths;

d) determining an etch quantity of the second material based on the standard patterns of the first material, the standard patterns of the mask layer, and the actual pattern of the second material; and

e) determining an etch quantity of the second material at a present point in time by a recurrent analysis using the old etch quantity of the second material obtained by step d).

5. A method of measuring an etch quantity of a material being processed, comprising:

a) setting a standard patterns, each consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed, that correspond to a plurality of predetermined etch quantities of the first material, respectively;

b) measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths;

c) determining an etch quantity of the second material based on the standard patterns of the first material and the actual pattern of the second material; and

d) estimating a time at which the etch quantity of the second material reaches a target value, by a recurrent analysis using the old etch quantity of the second material obtained by item c).

6. The etch quantity measuring method according to claim 5, comprising:

determining an etch rate by a recurrent analysis using the old etch quantity of the second material obtained by step c).

7. The etch quantity measuring method according to claim 5, comprising:

determining an initial thickness of the second material by a recurrent analysis using the old etch quantity of the second material obtained by step c).

8. The etch quantity measuring method according to claim 5, comprising:

determining an initial thickness and a remaining thickness of the second material by a recurrent analysis using the old etch quantity of the second material obtained by step c); and

determining an etch depth of the second material based on the initial thickness and the remaining thickness of the second material obtained.

9. A method of etching a material in a semiconductor device having a plurality of stacked films, comprising:

a) setting a standard patterns, each consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed, that correspond to a plurality of predetermined etch quantities of the first material, respectively;

b) measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths; and

c) determining an etch quantity of the second material based on the standard patterns of the first material and the actual pattern of the second material.

10. An apparatus for measuring a film process quantity in a semiconductor device manufacturing process, comprising:

a unit for setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed that corresponds to a predetermined film process quantity of the first material;

a unit for measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths; and

a unit for determining a film process quantity of the second material based on the standard pattern consisting of the time differential values and the actual pattern consisting of the time differential values.

11. An apparatus for measuring a film process quantity in a semiconductor device manufacturing process according to claim 10, comprising:

a unit for performing processing by changing a process condition when the film process quantity of the second material reaches a predetermined value.

12. An apparatus for measuring an etch quantity of a material being processed, comprising:

a unit for setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed that corresponds to a predetermined etch quantity of the first material including a mask layer;

a unit for setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from the mask layer of the first material that corresponds to a predetermined etch quantity of the mask layer;

a unit for measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths; and

a unit for determining an etch quantity of the second material based on the standard pattern of the first material, the standard pattern of the mask layer, and the actual pattern of the second material.

13. An apparatus for measuring an etch quantity of a material being processed, comprising:

a unit for setting a standard patterns, each consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed, that correspond to a plurality of predetermined etch quantities of the first material including a mask layer, respectively;

a unit for setting a standard patterns, each consisting of a time differential value of an interference light intensity for each of multiple wavelengths from the mask layer of the first materials that correspond to a plurality of predetermined etch quantities of the mask layer, respectively;

a unit for measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths;

a unit for determining an etch quantity of the second material based on the standard patterns of the first material, the standard patterns of the mask layer, and the actual pattern of the second material; and

a unit for determining an etch quantity of the second material at a present point in time by a recurrent analysis using the determined old etch quantity of the second material.

14. An apparatus for measuring an etch quantity of a material being processed, comprising:

a unit for setting a standard patterns, each consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed, that correspond to a plurality of predetermined etch quantities of the first material, respectively;

a unit for measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths;

unit for determining an etch quantity of the second material based on the standard patterns of the first material and the actual pattern of the second material; and

a unit for estimating a time at which the etch quantity of the second material reaches a target value, by a recurrent analysis using the determined old etch quantity of the second material.

15. The etch quantity measuring apparatus according to claim 14, comprising:

a unit for determining an initial thickness and a remaining thickness of the second material by a recurrent analysis using the determined old etch quantity of the second material; and

a unit for determining an etch depth of the second material based on the initial thickness and the remaining thickness of the second material obtained.

16. An apparatus for etching a material in semiconductor device having a plurality of stacked films, comprising:

a unit for setting a standard patterns, each consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed, that correspond to a plurality of predetermined etch quantities of the first material, respectively;

a unit for measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed of the same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths;

a unit for determining an etch quantity of the second material based on the standard patterns of the first material and the actual pattern of the second material;

a unit for determining a remaining thickness of the second material by a recurrent analysis using old etch quantity of the second material obtained by item c); and

a unit for performing etching by changing an etching condition when the determined remaining thickness of the material reaches a predetermined value.

17. A method of determining an endpoint of a semiconductor device manufacturing process comprising:

a) setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed corresponding to a predetermined etch quantity of the first material including a mask layer;

b) setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from the mask layer of the first material corresponding to a predetermined etch quantity of the mask layer;

c) measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed and which is of a same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths;

d) determining an etch quantity of the second material based on the standard pattern of the first material, the standard pattern of the mask layer, and the actual pattern of the time differential value second material; and

e) determining an end point of a process based on the etch quantity of the second material thus obtained.

18. A method of determining an endpoint of a process comprising:

setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed corresponding to a predetermined step height of the first material

setting a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from the first material to be processed corresponding to a predetermined remaining mask thickness of the first material;

measuring an intensity of an interference light for each of multiple wavelengths from a second material being processed which is of a same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths;

determining a step height and a mask remaining thickness of the second material being processed based on the standard pattern of the predetermined step height, the standard pattern of the predetermined remaining mask thickness and the actual patterns pattern of the second material; and

determining an end point of a process based on the step height and the mask remaining thickness of the second material thus obtained.

19. An apparatus for determining an endpoint of a semiconductor device manufacturing process comprising:

a unit which sets a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed corresponding to a predetermined etch quantity of the first material including a mask layer;

a unit which sets a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from the mask layer of the first material corresponding to a predetermined etch quantity of the mask layer;

a unit which measures an intensity of an interference light for each of multiple wavelengths from a second material being processed which is of a same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensities, the actual intensity for each of the multiple wavelengths;

a unit which determines an etch quantity of the second material based on the standard pattern of the first material, the standard pattern of the mask layer, and the actual pattern of the second material; and

a unit which determines an end point of a process based on the etch quantity of the second material thus obtained.

20. An apparatus for determining an endpoint of a process comprising:

a unit which sets a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from a first material to be processed corresponding to a predetermined step height of the first material;

a unit which sets a standard pattern consisting of a time differential value of an interference light intensity for each of multiple wavelengths from the first material to be processed corresponding to a predetermined remaining mask thickness of the first material;

a unit which measures an intensity of an interference light for each of multiple wavelengths from a second material being processed which is of a same structure as the first material and determining an actual pattern consisting of a time differential value of the measured interference light intensity for each of the multiple wavelengths;

a unit which determines a step height and a mask remaining thickness of the second material being processed based on the standard pattern of the predetermined step height, the standard pattern of the predetermined remaining mask thickness and the actual pattern of the time differential value second material; and

a unit which determines an end point of a process based on the step height and the mask remaining thickness of the second material thus obtained.