Laser trimming of resistors

• US 7,297,896 B2
• Filed: 10/19/2005
• Issued: 11/20/2007
• Est. Priority Date: 11/21/2002
• Status: Expired due to Term

• Current Assignee: Hadco Santa Clara Incorporated (Sanmina-SCI Corporation)
• Original Assignee: Hadco Santa Clara Incorporated (Sanmina-SCI Corporation)
• Inventors: Biunno, Nicholas, Patel, Atul, Dudnikov, George, Ogle, Ken
• Primary Examiner(s): Evans; Geoffrey S.
• Application Number:
  US11/254,253
• Publication Number:
  US 20060213882A1
• Time in Patent Office: 762 Days
• Field of Search: 700/166, 298/35, 298/36, 296/101, 338/195, 219/121.68, 219/121.69, 209/574
• US Class Current: 219/121.69
• CPC Class Codes: H01C 17/242 by laser trimming by laser in general B23K26/351
• CPC Class Codes: H05K 1/167 incorporating printed resistors

Abstract

Improved systems and methods for laser trimming resistors are provided. An exemplary embodiment measures a resistance value for each resistor and sorts the resistors into one or more bins based on the measured resistance values and target resistance values associated with each resistor. A laser trim file may then be assigned to each bin based on a predictive trim formulation, where each laser trim file defines a set of configuration parameters for a laser drill to conform each resistor with their respective target value. The laser drill uses the laser trim files to trim the resistors within each bin in accordance with the laser trim file assigned to that bin.

Claims

1. A method for laser trimming resistors, the method comprising:

measuring a resistance value for resistors of a set of resistors that are formed during manufacture of a circuit platform;

sorting the resistors into one or more bins based on the measured resistance values and target resistance values associated with each resistor;

assigning a laser trim file to bins based on a predictive trim formulation, each laser trim file defining a set of configuration parameters for a laser drill to conform each resistor with their respective target value; and

using the laser drill to trim the resistors within each bin in accordance with the laser trim file assigned to that bin;

wherein the laser trim file further defines a drill pattern on the resistor to form a planar channel within the resistor.

2. The method of claim 1, wherein at least a resistor in the set of resistors comprises a rectangular resistor.

3. The method of claim 1, wherein at least a resistor in the set of resistors comprises a serpentine resistor.

4. The method of claim 1, wherein at least a resistor in the set of resistors comprises an annular resistor.

5. The method of claim 1, wherein the resistors comprise a plurality of resistor geometries.

6. The method of claim 5, wherein the plurality of geometries comprises annular, rectangular and serpentine geometries.

7. The method of claim 1, further comprising:

measuring a resistance value of each trimmed resistor associated with a particular bin;

adjusting the laser trim file associated with the particular bin based on a distribution of the measured resistance values of the trimmed resistors within the particular bin;

displaying a distribution of the trimmed resistance values to assess performance of the laser drill file associated with the particular bin; and

displaying a distribution of the measured resistance values associated with each bin to assess performance of an underlying passive component formation process;

wherein the configuration parameters defined by the laser trim file include at least a spot size and power level for the laser drill, and the laser trim file includes at least a step size, an overlap factor and number of feed steps over the resistor to form the planar channel.

8. The method of claim 1, wherein at least a resistor in the set of resistors comprises a thick film polymer.

9. The method of claim 1, wherein at least a resistor in the set of resistors comprises a thin film polymer.

10. The method of claim 1, wherein at least a resistor in the set of resistors comprises a metal.

11. The method of claim 1, wherein at least a resistor in the set of resistors comprises a metal alloy.

12. The method of claim 1, wherein the resistors comprise a plurality of materials including polymers, metal and metal alloy.

13. The method of claim 1, wherein at least a resistor in the set of resistors is formed on an inner layer of a multilayer printed circuit board (MLB).

14. The method of claim 1, wherein at least a resistor in the set of resistors is formed on an outer layer of a multilayer printed circuit board (MLB).

15. The method of claim 1 wherein at least a resistor from the set of resistors is formed on a multi-chip module.

16. The method of claim 1 wherein at least a resistor from the set of resistors is formed on a flexible circuit structure.

17. The method of claim 1 wherein at least a resistor from the set of resistors is formed on an interposer flex.

18. A system for laser trimming resistors, the system comprising:

a tester configured to measure a resistance value for resistors of a set of resistors that are formed during manufacture of a circuit platform;

a trim application configured to;

sort the resistors into one or more bins based on the measured resistance values and target resistance values associated with each resistor, and

assign a laser trim file to each bin based on a predictive trim formulation to conform each resistor with their respective target value; and

a laser drill configured to trim the resistors within each bin in accordance with the laser trim file assigned to that bin, each laser trim file defining a set of configuration parameters for the laser drill;

wherein the laser trim file further defines a trim pattern on the resistor to form a planar channel within the resistor.

19. The system of claim 18, wherein at least a resistor in the set of resistors comprises a rectangular resistor or a serpentine resistor.

20. The system of claim 18, wherein:

the configuration parameters defined by the laser trim file include at least a spot size and power level for the laser drill;

the laser trim file includes at least a step size, an overlap factor and number of feed steps over the resistor to form the planar channel;

the tester is further configured to measure a resistance value of each trimmed resistor associated with a particular bin;

the laser trim application is further configured to adjust the laser trim file associated with the particular bin based on a distribution of the measured resistance values of the trimmed resistors within the particular bin;

the laser trim application is further configured to display a distribution of the trimmed resistance values to assess performance of the laser drill file associated with the particular bin; and

the laser trim application is further configured to display a distribution of the measured resistance values associated with each bin to assess performance of an underlying passive component formation process.

21. The system of claim 18, wherein at least a resistor in the set of resistors comprises at least a material from the set consisting of a thick film polymer, a thin film polymer, a metal, and a metal alloy.

22. The system of claim 18, wherein at least a resistor in the set of resistors is formed on an inner layer of a multilayer printed circuit board (MLB), an outer layer of a multilayer printed circuit board (MLB), a multi-chip module, a flexible circuit structure, or an interposer flex.

23. A computer program product comprising:

a computer usable medium having computer readable program code embodied therein, the computer readable program code comprising;

computer readable program code that receives a resistance value for resistors of a set of resistors that are formed during manufacture of a circuit platform;

computer readable program code that sorts the resistors into one or more bins based on the measured resistance values and target resistance values associated with each resistor;

computer readable program code that assigns a laser trim file to each bin based on a predictive trim formulation, each laser trim file defining a set of configuration parameters for a laser drill to conform each resistor with their respective target value; and

computer readable program code that outputs, for uploading to the laser drill, a file having assignment of the respective resistors to respective laser trim files.

24. The computer program product of claim 23, wherein at least a resistor in the set of resistors comprises a rectangular resistor or a serpentine resistor.

25. The computer program product of claim 23, wherein at least a resistor in the set of resistors comprises at least a material from the set consisting of a thick film polymer, a thin film polymer, a metal, and a metal alloy.

26. The computer program product of claim 23, wherein at least a resistor in the set of resistors is formed on an inner layer of a multilayer printed circuit board (MLB), an outer layer of a multilayer printed circuit board (MLB), a multi-chip module, a flexible circuit structure, or an interposer flex.

27. The computer program product of claim 23, further comprising:

computer readable program code that receives a resistance value of each trimmed resistor associated with a particular bin;

computer readable program code that adjusts the laser trim file associated with the particular bin based on a distribution of the measured resistance values of the trimmed resistors within the particular bin;

computer readable program code that displays a distribution of the trimmed resistance values to assess performance of the laser drill file associated with the particular bin; and

computer readable program code that displays a distribution of the measured resistance values associated with each bin to assess performance of an underlying passive component formation process;

wherein the configuration parameters defined by the laser trim file include at least a spot size and power level for the laser drill, and the laser trim file includes at least a step size, an overlap factor and number of feed steps over the resistor to form the planar channel.

28. A computer software tool for use in laser trimming comprising:

a library of laser trim files, each laser trim file defining a set of configuration parameters for a laser drill to conform resistors with their respective target values;

a computer usable medium having computer readable program code embodied therein, the computer readable program code comprising;

computer readable program code that receives a resistance value for resistors of a set of resistors that are formed during manufacture of a circuit platform;

computer readable program code that sorts the resistors into one or more bins based on the measured resistance values and target resistance values associated with each resistor;

computer readable program code that assigns a laser trim file from the library to each bin based on a predictive trim formulation; and

computer readable program code that outputs, for uploading to the laser drill, a file having assignment of the respective resistors to respective laser trim files.

29. The computer software tool of claim 28, wherein at least a resistor in the set of resistors comprises a rectangular resistor or a serpentine resistor.

30. The computer software tool of claim 28, wherein at least a resistor in the set of resistors comprises at least a material from the set consisting of a thick film polymer, a thin film polymer, a metal, and a metal alloy.

31. The computer software tool of claim 28, wherein at least a resistor in the set of resistors is formed on an inner layer of a multilayer printed circuit board (MLB), an outer layer of a multilayer printed circuit board (MLB), a multi-chip module, a flexible circuit structure, or an interposer flex.