Point-of-use mixing method with first derivative homogeneity monitoring

• US 20070106425A1
• Filed: 07/10/2006
• Published: 05/10/2007
• Est. Priority Date: 07/08/2005
• Status: Abandoned Application

• Current Assignee: Tres-Ark, Inc.
• Original Assignee: Tres-Ark, Inc.
• Inventors: Anderson, Gary, Fowler, Matt
• Application Number:
  US11/484,019
• Publication Number:
  US 20070106425A1
• Time in Patent Office: Days
• US Class Current: 700/265
• CPC Class Codes: B01F 33/84 Mixing plants with mixing receptacles receiving material dispensed from several component receptacles, e.g. paint tins
• CPC Class Codes: B01F 35/213 of the properties of the mixtures, e.g. temperature, density or colour
• CPC Class Codes: G05D 11/133 with discontinuous action
• CPC Class Codes: G05D 11/139 by measuring a value related to the quantity of the individual components and sensing at least one property of the mixture
• CPC Class Codes: H01L 21/67253 Process monitoring, e.g. flow or thickness monitoring

Abstract

There is disclosed a system and method of formulating a batch comprising at least two chemicals. An embodiment is disclosed wherein a feedforward algorithm can be used to control the target blend. Subsequently a feedback closed loop control loop algorithm is provided for a multivariant blend. Use of this approach allows for a continuously autoreplenished and controlled blend. Also disclosed is the ability to control via feedforward and feedback algorithms a fast responding control mode that allows for the elimination of a container. This approach will allow for “one pass” blending with control. The controller implements an automated fault detection and correction system, thereby identifying necessary maintenance prior to failure. If failure does occur the signature recognition allows rapid analysis and correction thus maximizing tool availability.

Claims

1. A method of producing a composition, the composition comprising two or more chemicals, the method comprising:

obtaining a total flow rate for the composition;

determining the flow rate for each chemical, wherein the sum of the flow rates for each chemical equals the total flow rate, and wherein the flow rate of each chemical is determined based on a predetermined composition formulation;

initiating flow of each chemical into a mixing area, wherein each chemical is flowed at the determined flow rate, and wherein the chemicals are combined in the mixing area to produce the composition;

transferring the composition into an analyzer, wherein the analyzer is configured to measure the quantity of one or more chemicals of the composition;

determining the homogeneity of the composition as the composition is flowed through the analyzer, wherein the homogeneity is determined as a function of an average deviation of the quantity of one or more chemicals of the composition with respect to an average quantity of the chemicals of the composition over a predetermined time period;

designating the composition as properly mixed if one or more chemicals of the composition is within a predetermined concentration range and if the homogeneity of the composition is at least at a predetermined homogeneity value.

2. The method of claim 1, wherein determining the average deviation comprises:

collecting a predetermined number of quantity measurements for one or more chemicals in the composition over a predetermined time period;

determining the average quantity of one or more chemicals in the composition for the plurality of concentration measurements taken over the predetermined time period;

determining, for each measured quantity of one or more chemicals of the composition, the standard deviation of the measured quantity with respect to the average quantity;

determining one or more average standard deviation values of one or more of the chemicals;

determining the homogeneity of the composition, wherein the homogeneity of the composition is a function of one or more average standard deviations.

3. The method of claim 2, wherein the composition comprises two or more chemicals, wherein the homogeneity of the composition is a function of the average standard deviation of two or more chemicals.

4. The method of claim 1, further comprising transferring the properly mixed composition to a semiconductor fabrication tool.

5. The method of claim 1, wherein the composition is produced as a continuously flowing composition.

6. The method of claim 1, wherein the composition comprises an aqueous solution of one or more chemicals.

7. The method of claim 1, wherein at least one of the chemical is an inorganic base.

8. The method of claim 1, wherein at least one of the chemicals is a mineral acid.

9. The method of claim 1, wherein at least one of the chemicals is hydrogen peroxide.

10. The method of claim 1, wherein at least one analyzer is a spectral absorption analytical device.

11. The method of claim 1, wherein at least one analyzer is a conductance measurement device.

12. The method of claim 1, wherein at least one analyzer is a Raman spectrophotometer.

13. The method of claim 1, wherein the composition, after passing through the analyzer is passed to a waste drain if one or more of the chemicals are not within a predetermined quantity range.

14. The method of claim 1, further comprising determining error correction values if one or more chemicals are not within a predetermined quantity range.

15. The method of claim 14, wherein determining the flow rate for each chemical comprises using one or more error correction values to determine the flow rate, wherein the one or more error correction values are obtained from previous use of the system.

16. The method of claim 1, further comprising adjusting the flow rate of one or more chemicals based on the measured quantity of one or more of the chemicals.

17. The method of claim 1, further comprising adjusting the flow rate of each of the chemicals if one or more chemicals of the composition are not within a predetermined quantity range.

18. The method of claim 1, wherein prior to initiating flow of each chemical into the mixing area, the method further comprises:

sending a zero point control signal from a controller to at least one chemical dispensing device, wherein the zero point control signal causes the chemical dispensing device to move to a zero flow state configuration;

detecting if a fluid is flowing through one or more of the chemical dispensing devices after the chemical dispensing device receives the zero point control signal, wherein if fluid flow is detected through one or more of the chemical dispensing devices, one or more of the chemical dispensing devices are adjusted until flow of fluid through the one or more chemical dispensing devices is inhibited.

19. A method of producing a composition, the composition comprising two or more chemicals, the method comprising:

obtaining a total flow rate for the composition;

determining the flow rate for each chemical, wherein the sum of the flow rates for each chemical equals the total flow rate, and wherein the flow rate of each chemical is determined based on a predetermined composition formulation;

initiating flow of each chemical into a mixing area, wherein each chemical is flowed at the determined flow rate, and wherein the chemicals are combined in the mixing area to produce the composition;

transferring the composition into an analyzer, wherein the analyzer is configured to measure the quantity of one or more chemicals of the composition;

determining the homogeneity of the composition as the composition is flowed through the analyzer, wherein the homogeneity is determined as a function of an average change in the quantity of one or more chemicals of the composition over a predetermined time period;

designating the composition as properly mixed if one or more chemicals of the composition is within a predetermined concentration range and if the homogeneity of the composition is at least at a predetermined homogeneity value.

20. The method of claim 19, wherein determining an average change in quantity comprises:

taking a plurality of quantity measurements of the composition over a predetermined time period;

determining the change in quantity with respect to time for each quantity measurement;

determining one or more average change in quantity with respect to time of one or more of the chemicals;

determining the homogeneity of the composition, wherein the homogeneity of the composition is a function of one or more average changes.

21. The method of claim 20, wherein the composition comprises two or more chemicals, wherein the homogeneity of the composition is a function of the average changes of two or more chemicals.

22. The method of claim 19, further comprising transferring the properly mixed composition to a semiconductor fabrication tool.

23. The method of claim 19, wherein the composition is produced as a continuously flowing composition.

24. The method of claim 19, wherein the composition comprises an aqueous solution of one or more chemicals.

25. The method of claim 19, wherein at least one of the chemical is an inorganic base.

26. The method of claim 19, wherein at least one of the chemicals is a mineral acid.

27. The method of claim 19, wherein at least one of the chemicals is hydrogen peroxide.

28. The method of claim 19, wherein at least one analyzer is a spectral absorption analytical device.

29. The method of claim 19, wherein at least one analyzer is a conductance measurement device.

30. The method of claim 19, wherein at least one analyzer is a Raman spectrophotometer.

31. The method of claim 19, wherein the composition, after passing through the analyzer is passed to a waste drain if one or more of the chemicals are not within a predetermined quantity range.

32. The method of claim 19, further comprising determining error correction values if one or more chemicals are not within a predetermined quantity range.

33. The method of claim 32, wherein determining the flow rate for each chemical comprises using one or more error correction values to determine the flow rate, wherein the one or more error correction values are obtained from previous use of the system.

34. The method of claim 19, further comprising adjusting the flow rate of one or more chemicals based on the measured quantity of one or more of the chemicals.

35. The method of claim 19, further comprising adjusting the flow rate of each of the chemicals if one or more chemicals of the composition are not within a predetermined quantity range.

36. The method of claim 19, wherein prior to initiating flow of each chemical into the mixing area, the method further comprises:

sending a zero point control signal from a controller to at least one chemical dispensing device, wherein the zero point control signal causes the chemical dispensing device to move to a zero flow state configuration;

detecting if a fluid is flowing through one or more of the chemical dispensing devices after the chemical dispensing device receives the zero point control signal, wherein if fluid flow is detected through one or more of the chemical dispensing devices, one or more of the chemical dispensing devices are adjusted until flow of fluid through the one or more chemical dispensing devices is inhibited.

37. A method of formulating a composition comprising two or more chemicals, comprising:

dispensing at least two chemicals into a container until the container is filled to a predetermine volume;

determining the homogeneity of the composition while the container is being filled and/or after the container is filled to the predetermined volume, wherein the homogeneity is determined as a function of an average deviation of the quantity of one or more chemicals of the composition with respect to an average quantity of the chemicals of the composition over a predetermined time period;

determining the quantity of one or more of the chemicals in the container after the homogeneity of the mixture is at least at a predetermined homogeneity value.

38. The method of claim 37, wherein determining the average deviation comprises:

collecting a predetermined number of quantity measurements for one or more chemicals in the composition over a predetermined time period;

determining the average quantity of one or more chemicals in the composition for the plurality of quantity measurements taken over the predetermined time period;

determining, for each measured quantity of one or more chemicals of the composition, the standard deviation of the measured quantity with respect to the average quantity;

determining one or more average standard deviation values of one or more of the chemicals;

determining the homogeneity of the composition, wherein the homogeneity of the composition is a function of one or more average standard deviations.

39. The method of claim 38, wherein the composition comprises two or more chemicals, wherein the homogeneity of the composition is a function of the average standard deviation of two or more chemicals.

40. The method of claim 37, wherein dispensing the at least two chemicals into the container until the container is filled to a predetermine volume comprises:

admitting at least two chemicals to a container until the container is partially filled to a fraction of the full container volume;

determining the homogeneity of the mixture in the partially filled container;

determining the quantity of each chemical needed to fill the container to the predetermined volume, wherein the quantity of each chemical is calculated as a function of the determined quantity of one or more of the chemicals in the mixture;

dispensing the determined quantity of the chemicals to the container.

41. The method of claim 40, wherein determining the amount of each chemical needed to fill the container comprises:

calculating a correction factor for at least one of the chemicals, wherein the correction factor is the ratio of a target quantity to the determined quantity for at least one of the chemicals in the partially filled container;

calculating the theoretical amount of each of the chemicals needed to fill the container to a second fraction of the full container volume by determining the difference between the desired quantity of chemical in the container when filled to the second fraction of the full container volume and the determined quantity of the chemical in the partially filled container; and

calculating the actual amount of each of the chemicals needed to fill the container to a predetermined volume by multiplying one or more of the calculated theoretical amounts by the correction factor.

42. The method of claim 40, wherein determining the amount of each chemical needed to fill the container comprises:

calculating a correction factor for at least one of the chemicals, wherein the correction factor is the ratio of a target quantity to the determined quantity for at least one of the chemicals when dispensed into a container, wherein the correction factor is determined prior to formulating the composition;

calculating the theoretical amount of each of the chemicals needed to fill the container to a second fraction of the full container volume by determining the difference between the desired quantity of chemical in the container when filled to the second fraction of the full container volume and the determined quantity of the chemical in the partially filled container, and

calculating the actual amount of each of the chemicals needed to fill the container to a predetermined volume by multiplying one or more of the calculated theoretical amounts by the correction factor.

43. The method of claim 40, further comprising repeatedly performing the following until the predetermined volume of the composition is obtained:

determining the amount of each chemical needed to fill the container to one or more additional fractions of the full container volume, wherein the amount of each chemical added for each additional fraction is calculated as a function of the determined quantity of one or more of the chemicals in the partially filled container;

dispensing the determined amount of the chemicals into the container.

44. The method of claim 37, wherein if at least a portion of the composition is removed from the container, the method further comprises:

determining the quantity of one or more of the chemicals in the remaining composition;

determining the volume of chemicals needed to at least partially refill the container;

determining the amount of each chemical needed to produce the determined volume, wherein the amount of each chemical is calculated as a function of the determined quantity of one or more of the chemicals in the remaining composition; and

dispensing the determined amount of the chemicals into the container.

45. The method of claim 37, wherein determining the quantity of one or more of the chemicals in the container comprises determining a weight percentage of one or more of the chemicals.

46. The method of claim 37, wherein one chemical of the composition is water.

47. The method of claim 37, wherein one chemical of the composition is an inorganic base.

48. The method of claim 37, wherein one chemical of the composition is ammonium hydroxide.

49. The method of claim 37, wherein one chemical of the composition is a mineral acid.

50. The method of claim 37, wherein one chemical of the composition is hydrogen peroxide.

51. The method of claim 37, wherein the composition comprises a mixture of ammonium hydroxide, hydrogen peroxide, and water.

52. The method of claim 37, wherein the composition comprises a mixture of hydrogen chloride, hydrogen peroxide, and water.

53. The method of claim 37, wherein the composition comprises a mixture of sulfuric acid, hydrogen peroxide, and water.

54. The method of claim 37, wherein the composition comprises a mixture of ammonium hydroxide, hydrogen fluoride, and water.

55. The method of claim 37, wherein determining a quantity of one or more of the chemicals in the container comprises determining one or more spectroscopic properties of the composition.

56. The method of claim 55, wherein at least one of the spectroscopic properties is Raman spectroscopy.

57. The method of claim 37, wherein determining a quantity of one or more of the chemicals in the container comprises determining a conductance of the composition.

58. The method of claim 37, wherein one or more chemicals are supplied to the container from a bulk chemical storage, the method further comprising blending one or more of the chemicals with water prior to dispensing the chemical into the container.

59. The method of claim 37, wherein prior to dispensing at least two chemicals into the container, the method further comprises:

sending a zero point control signal from a controller to at least one chemical dispensing device, wherein the zero point control signal causes the chemical dispensing device to move to a zero flow state configuration;

detecting if a fluid is flowing through one or more of the chemical dispensing devices after the chemical dispensing device receives the zero point control signal, wherein if fluid flow is detected through one or more of the chemical dispensing devices, one or more of the chemical dispensing devices are adjusted until flow of fluid through the one or more chemical dispensing devices is inhibited.

60. The method of claim 37, further comprising transferring the composition to a semiconductor fabrication tool.

61. A method of formulating a composition comprising two or more chemicals, comprising:

dispensing at least two chemicals into a container until the container is filled to a predetermine volume;

determining the homogeneity of the composition while the container is being filled and/or after the container is filled to the predetermined volume, wherein the homogeneity is determined as a function of an average change in the quantity of one or more chemicals of the composition over a predetermined time period;

determining the quantity of one or more of the chemicals in the container after the homogeneity of the mixture is at least at a predetermined homogeneity value.

62. The method of claim 61, wherein determining an average change in quantity comprises:

taking a plurality of quantity measurements of the composition over a predetermined time period;

determining the change in quantity with respect to time for each quantity measurement;

determining one or more average change in quantity with respect to time of one or more of the chemicals;

determining the homogeneity of the composition, wherein the homogeneity of the composition is a function of one or more average changes.

63. The method of claim 62, wherein the composition comprises two or more chemicals, wherein the homogeneity of the composition is a function of the average change of two or more chemicals.

64. The method of claim 61, wherein dispensing the at least two chemicals into the container until the container is filled to a predetermine volume comprises:

admitting at least two chemicals to a container until the container is partially filled to a fraction of the full container volume;

determining the homogeneity of the mixture in the partially filled container;

determining the quantity of each chemical needed to fill the container to the predetermined volume, wherein the quantity of each chemical is calculated as a function of the determined quantity of one or more of the chemicals in the mixture;

dispensing the determined quantity of the chemicals to the container.

65. The method of claim 64, wherein determining the amount of each chemical needed to fill the container comprises:

calculating a correction factor for at least one of the chemicals, wherein the correction factor is the ratio of a target quantity to the determined quantity for at least one of the chemicals in the partially filled container;

calculating the theoretical amount of each of the chemicals needed to fill the container to a second fraction of the full container volume by determining the difference between the desired quantity of chemical in the container when filled to the second fraction of the full container volume and the determined quantity of the chemical in the partially filled container; and

calculating the actual amount of each of the chemicals needed to fill the container to a predetermined volume by multiplying one or more of the calculated theoretical amounts by the correction factor.

66. The method of claim 64, wherein determining the amount of each chemical needed to fill the container comprises:

calculating a correction factor for at least one of the chemicals, wherein the correction factor is the ratio of a target quantity to the determined quantity for at least one of the chemicals when dispensed into a container, wherein the correction factor is determined prior to formulating the composition;

calculating the theoretical amount of each of the chemicals needed to fill the container to a second fraction of the full container volume by determining the difference between the desired quantity of chemical in the container when filled to the second fraction of the full container volume and the determined quantity of the chemical in the partially filled container; and

calculating the actual amount of each of the chemicals needed to fill the container to a predetermined volume by multiplying one or more of the calculated theoretical amounts by the correction factor.

67. The method of claim 64, further comprising repeatedly performing the following until the predetermined volume of the composition is obtained:

determining the amount of each chemical needed to fill the container to one or more additional fractions of the full container volume, wherein the amount of each chemical added for each additional fraction is calculated as a function of the determined quantity of one or more of the chemicals in the partially filled container;

dispensing the determined amount of the chemicals into the container.

68. The method of claim 61, wherein if at least a portion of the composition is removed from the container, the method further comprises:

determining the quantity of one or more of the chemicals in the remaining composition;

determining the volume of chemicals needed to at least partially refill the container;

determining the amount of each chemical needed to produce the determined volume, wherein the amount of each chemical is calculated as a function of the determined quantity of one or more of the chemicals in the remaining composition; and

dispensing the determined amount of the chemicals into the container.

69. The method of claim 61, wherein determining the quantity of one or more of the chemicals in the container comprises determining a weight percentage of one or more of the chemicals.

70. The method of claim 61, wherein one chemical of the composition is water.

71. The method of claim 61, wherein one chemical of the composition is an inorganic base.

72. The method of claim 61, wherein one chemical of the composition is ammonium hydroxide.

73. The method of claim 61, wherein one chemical of the composition is a mineral acid.

74. The method of claim 61, wherein one chemical of the composition is hydrogen peroxide.

75. The method of claim 61, wherein the composition comprises a mixture of ammonium hydroxide, hydrogen peroxide, and water.

76. The method of claim 61, wherein the composition comprises a mixture of hydrogen chloride, hydrogen peroxide, and water.

77. The method of claim 61, wherein the composition comprises a mixture of sulfuric acid, hydrogen peroxide, and water.

78. The method of claim 61, wherein the composition comprises a mixture of ammonium hydroxide, hydrogen fluoride, and water.

79. The method of claim 61, wherein determining a quantity of one or more of the chemicals in the container comprises determining one or more spectroscopic properties of the composition.

80. The method of claim 79, wherein at least one of the spectroscopic properties is Raman spectroscopy.

81. The method of claim 61, wherein determining a quantity of one or more of the chemicals in the container comprises determining a conductance of the composition.

82. The method of claim 61, wherein one or more chemicals are supplied to the container from a bulk chemical storage, the method further comprising blending one or more of the chemicals with water prior to dispensing the chemical into the container.

83. The method of claim 61, wherein prior to dispensing at least two chemicals into the container, the method further comprises:

sending a zero point control signal from a controller to at least one chemical dispensing device, wherein the zero point control signal causes the chemical dispensing device to move to a zero flow state configuration;

detecting if a fluid is flowing through one or more of the chemical dispensing devices after the chemical dispensing device receives the zero point control signal, wherein if fluid flow is detected through one or more of the chemical dispensing devices, one or more of the chemical dispensing devices are adjusted until flow of fluid through the one or more chemical dispensing devices is inhibited.

84. The method of claim 61, further comprising transferring the composition to a semiconductor fabrication tool.