Batch mixing method with first derivative homogeneity monitoring

• US 7,363,115 B2
• Filed: 07/10/2006
• Issued: 04/22/2008
• Est. Priority Date: 07/08/2005
• Status: Expired due to Fees

• Current Assignee: Tres Ark
• Original Assignee: Tres-Ark, Inc.
• Inventors: Fowler, Matt, Anderson, Gary R.
• Primary Examiner(s): Cabrera; Zoila
• Assistant Examiner(s): LAUGHLIN, NATHAN L
• Application Number:
  US11/484,020
• Publication Number:
  US 20070043472A1
• Time in Patent Office: 652 Days
• Field of Search: 700/266, 700/265, 700/285, 702/23, 702/25, 702/30, 366/152.1, 366/136, 366/132
• US Class Current: 700/285
• 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 formulating a composition having a predetermined volume comprising two or more chemicals, each chemical being present in the composition in a predetermined quantity, the method comprising:

admitting at least two chemicals into a container to form a composition until the container is partially filled to a predetermined fraction of the predetermined volume;

blending the composition in the container;

determining the homogeneity of the blended composition;

continuing blending of the composition until the homogeneity of the composition is at least at a predetermined homogeneity value;

determining the quantity of each chemical needed to fill the container to the predetermined volume, or to a selected volume between the volume of the partially filled container and the predetermined volume, after the homogeneity of the composition is at least at a predetermined homogeneity value, wherein the quantity of each chemical is calculated as a function of the determined quantity of one or more of the chemicals in the composition; and

dispensing the determined quantity of the chemicals to the container;

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.

2. The method of claim 1, 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.

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 change of two or more chemicals.

4. The method of claim 1, wherein determining the quantity of each chemical needed to fill the container to the predetermined volume 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 the predetermined volume by determining the difference between the predetermined quantity of chemical in the container when filled to the predetermined 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 the predetermined volume by multiplying one or more of the calculated theoretical amounts by the correction factor.

5. The method of claim 1, 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 predetermined 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 after the homogeneity of the intermediate composition is determined;

dispensing the determined amount of the chemicals into the container.

6. The method of claim 1, 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.

7. The method of claim 1, 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.

8. The method of claim 1, wherein one chemical of the composition is water.

9. The method of claim 1, wherein one chemical of the composition is an inorganic base.

10. The method of claim 1, wherein one chemical of the composition is ammonium hydroxide.

11. The method of claim 1, wherein one chemical of the composition is a mineral acid.

12. The method of claim 1, wherein one chemical of the composition is hydrogen peroxide.

13. The method of claim 1, wherein the composition comprises a mixture of animonium hydroxide, hydrogen peroxide, and water.

14. The method of claim 1, wherein the composition comprises a mixture of hydrogen chloride, hydrogen peroxide, and water.

15. The method of claim 1, wherein the composition comprises a mixture of sulfuric acid, hydrogen peroxide, and water.

16. The method of claim 1, wherein the composition comprises a mixture of ammonium hydroxide, hydrogen fluoride, and water.

17. The method of claim 1, wherein determining a quantity of one or more of the chemicals in the container comprises determining one or more spectroscopic properties of the composition.

18. The method of claim 17, wherein at least one of the spectroscopic properties is Raman spectroscopy.

19. The method of claim 1, wherein determining a quantity of one or more of the chemicals in the container comprises determining a conductance of the composition.

20. The method of claim 1, 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.

21. The method of claim 1, 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.

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