US5495089A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Laser soldering surface mount components of a printed circuit board
Assignee: Hewlett Packard Development Co LP
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Filing: 1993-06-04
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Granted: 1996-02-27
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Expires: 2013-06-04
Abstract
Abstract This disclosure relates to a process for laser soldering surface mount components on a printed circuit board using the continuous wave laser scanning technique. The process involves factoring together the scan rate, the beam diameter, and the laser power level, in order to determine what these specific process variables should be. In addition, the process also involves taking account of the depth of a metallic layer, such as a reference plane, inside the printed circuit board to determine its effect on other process variables. On the other hand, if the board does not have a metallic layer, the process takes account of the thickness of the board being processed. Preferred ranges for process variables are identified, as well as optimization techniques which further refine the process variables to achieve production efficiency or bonding pull strength.
Inventors
- 👤 Gary M. Freedman
- 👤 Maurice P. Brodeur
- 👤 Peter J. Elmgren
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:00
CPC Classifications
B; B23; B23K; B23K26/00; B23K26/08; B23K26/0869; B23K26/0876; B23K26/0884; B23K1/00; B23K1/005; B23K1/0056; H; H05; H05K; H05K3/00; H05K3/30; H05K3/32; H05K3/34; H05K3/3494; B23K2101/00; B23K2101/36; B23K2101/40; H05K2203/00; H05K2203/10; H05K2203/107; H05K3/341; H05K3/3421; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/49117; Y10T29/49124; Y10T29/4913; Y10T29/49144
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
112 words
A method of laser bonding comprising the steps of: irradiating a first conductive element, which is in contact with a second conductive element, with a continuous wave laser beam characterized by a power level (P), a beam diameter (B) and a scan rate (S) at which said beam moves relative to one of said first and second conductive elements; determining at least one of said power level, said beam diameter and said scan rate using an equation having a form S=aB.sup.2 +bB+cP+dT+e where "a", "b", "c", "d", and "e" have predetermined values, and "T" represents a thickness of a substrate on which one of said first and second conductive elements is mounted.
Claim 2
Independent Claim
112 words
A method of laser bonding comprising the steps of: irradiating a first conductive element, which is in contact with a second conductive element, with a continuous wave laser beam characterized by a power level (P), a beam diameter (B) and a scan rate (S) at which said beam moves relative to one of said first and second conductive elements; determining at least one of said power level, said beam diameter and said scan rate using an equation having a form S=aB.sup.2 +bB+cP+dT+e where "a", "b", "c", "d", and "e" have predetermined values, and "T" represents a thickness of a substrate on which one of said first and second conductive elements is mounted.
Claim 3
Dependent Claim
18 words
The method in accordance with claim 1, wherein said substrate comprises a printed circuit board comprising dielectric material.
Claim 4
Dependent Claim
16 words
The method of claim 1, wherein the equation is generally in the form: S=-1777.78B.sup.2 +113.89B+0.87P-191.43T+2.96 4.
Claim 5
Independent Claim
150 words
A method of laser bonding a first conductive element and a second conductive element disposed in contact with said first conductive element and on a mounting surface of a substrate, said substrate comprising a conductive plane and a dielectric layer disposed between said conductive plane and said mounting surface, said method comprising the steps of: irradiating said first and second conductive elements with a continuous wave laser beam characterized by a power level (P), a beam diameter (B) and a scan rate (S) at which the beam moves relative to one of said first and second conductive elements; determining at least one of said power level (P), said beam diameter (B) and said scan rate (S) using an equation having a form S=aB.sup.2 +bB+cP+dD+e where "a", "b", "c", "d", and "e" have predetermined values, and "D" represents a distance between said conductive plane and said mounting surface of said substrate.
Claim 6
Independent Claim
150 words
A method of laser bonding a first conductive element and a second conductive element disposed in contact with said first conductive element and on a mounting surface of a substrate, said substrate comprising a conductive plane and a dielectric layer disposed between said conductive plane and said mounting surface, said method comprising the steps of: irradiating said first and second conductive elements with a continuous wave laser beam characterized by a power level (P), a beam diameter (B) and a scan rate (S) at which the beam moves relative to one of said first and second conductive elements; determining at least one of said power level (P), said beam diameter (B) and said scan rate (S) using an equation having a form S=aB.sup.2 +bB+cP+dD+e where "a", "b", "c", "d", and "e" have predetermined values, and "D" represents a distance between said conductive plane and said mounting surface of said substrate.
Claim 7
Dependent Claim
24 words
The method in accordance with claim 4, wherein said substrate comprises a printed circuit board, and said conductive plane comprises a voltage reference plane.
Claim 8
Dependent Claim
15 words
The method of claim 4, wherein the equation is generally in the form: S=-1777.78B.sup.2 +113.89B+0.87P-191.43D+2.96
Claim 9
Independent Claim
127 words
A method of laser bonding a first conductive element and a second conductive element disposed in contact with said first conductive element and on a mounting surface of a substrate having a thickness (T), comprising the steps of: irradiating said first conductive element, which is in contact with said second conductive element, with a continuous wave laser beam characterized by a plurality of parameters including a power level (P), a beam diameter (B) and a scan rate (S) at which said beam moves relative to one of said first and second conductive elements; determining at least one of said beam diameter (B), said power level (P) and said scan rate (S) using a functional relationship between at least one of said parameters and said substrate thickness (T).
Claim 10
Independent Claim
127 words
A method of laser bonding a first conductive element and a second conductive element disposed in contact with said first conductive element and on a mounting surface of a substrate having a thickness (T), comprising the steps of: irradiating said first conductive element, which is in contact with said second conductive element, with a continuous wave laser beam characterized by a plurality of parameters including a power level (P), a beam diameter (B) and a scan rate (S) at which said beam moves relative to one of said first and second conductive elements; determining at least one of said beam diameter (B), said power level (P) and said scan rate (S) using a functional relationship between at least one of said parameters and said substrate thickness (T).
Claim 11
Dependent Claim
49 words
The method of claim 7, wherein said step of determining at least one of said power level (P), said beam diameter (B) and said scan rate (S) comprises the step of using an equation having a form S=aB.sup.2 +bB+cP+dT+e where "a", "b", "c", "d", and "e" have predetermined values.
Claim 12
Dependent Claim
19 words
The method in accordance with claim 7, wherein further said substrate comprises a printed circuit board comprising dielectric material.
Claim 13
Dependent Claim
17 words
The method of claim 7, wherein said functional relationship is generally in the form: S=-1777.78B.sup.2 +113.89B+0.87P-191.43T+2.96 11.
Claim 14
Dependent Claim
45 words
The method of claim 7, wherein said step of determining at least one of said beam diameter (B), said power level P and said scan rate (S) includes the step of using a linear relationship between said scan rate (S) and said substrate thickness (T).
Claim 15
Dependent Claim
45 words
The method of claim 7, wherein said step of determining at least one of said beam diameter (B), said power level (P) and said scan rate (S) includes the step of using a linear relationship between said power level (P) and said substrate thickness (T).
Claim 16
Dependent Claim
47 words
The method of claim 7, wherein said step of determining at least one of said beam diameter (B), said power level (P) and said scan rate (S) includes the step of using a quadratic formula expressing said substrate thickness (T) in terms of said beam diameter (B).
Claim 17
Dependent Claim
62 words
The method of claim 7, wherein said step of determining at least one of said beam diameter (B), said power level (P) and said scan rate (S) includes the step of using a formula expressing said scan rate (S) as a quadratic function of said beam diameter (B), and a linear function of said power level (P) and said substrate thickness (T).
Claim 18
Dependent Claim
72 words
The method of claim 7, wherein said step of determining at least one of said power level (P) and said scan rate (S) uses a linear relationship between said scan rate (S) and said power level (P), a linear relationship between said scan rate (S) and said substrate thickness (T) and a linear relationship between said power level (P) and said substrate thickness (T) in determining at least one of said parameters.
Claim 19
Independent Claim
142 words
A method of laser bonding a first conductive element and a second conductive element disposed in contact with said first conductive element and on a mounting surface of a substrate, said substrate comprising a conductive plane and a dielectric layer disposed between said conductive plane and said mounting surface, said method comprising the steps of: irradiating said first and second conductive elements with a continuous wave laser beam characterized by a power level (P), a beam diameter (B) and a scan rate (S) at which the beam moves relative to one of said first and second conductive elements; determining at least one of said power level (P), said beam diameter (B) and said scan rate (S) using a functional relationship between at least one of said parameters and a distance (D) between said conductive plane and said mounting surface of said substrate.
Claim 20
Independent Claim
142 words
A method of laser bonding a first conductive element and a second conductive element disposed in contact with said first conductive element and on a mounting surface of a substrate, said substrate comprising a conductive plane and a dielectric layer disposed between said conductive plane and said mounting surface, said method comprising the steps of: irradiating said first and second conductive elements with a continuous wave laser beam characterized by a power level (P), a beam diameter (B) and a scan rate (S) at which the beam moves relative to one of said first and second conductive elements; determining at least one of said power level (P), said beam diameter (B) and said scan rate (S) using a functional relationship between at least one of said parameters and a distance (D) between said conductive plane and said mounting surface of said substrate.
Claim 21
Dependent Claim
52 words
The method of claim 7, wherein said step of determining at least one of said beam diameter (B), said power level (P) and said scan rate (S) includes the step of using a linear relationship between said scan rate (S) and said distance (D) between said conductive plane and said mounting surface.
Claim 22
Dependent Claim
52 words
The method of claim 7, wherein said step of determining at least one of said beam diameter (B), said power level (P) and said scan rate (S) includes the step of using a linear relationship between said power level (P) and said distance (D) between said conductive plane and said mounting surface.
Claim 23
Dependent Claim
53 words
The method of claim 7, wherein said step of determining at least one of said beam diameter (B), said power level (P) and said scan rate (S) includes the step of using a quadratic formula expressing said distance (D) between said conductive plane and said mounting surface in terms of beam diameter (B).
Claim 24
Dependent Claim
68 words
The method of claim 7, wherein said step of determining at least one of said beam diameter (B), said power level (P) and said scan rate (S) includes the step of using a formula expressing said scan rate as a quadratic function of said beam diameter (B), and a linear function of said power level (P) and said distance (D) between said conductive plane and said mounting surface.
Claim 25
Dependent Claim
66 words
The method of claim 7, wherein said step of determining at least one of said power level (P) and said scan rate (S) uses a linear relationship between said scan rate (S) and said power level (P), a linear relationship between said scan rate (S) and said distance (D) and a linear relationship between said power level (P) and said distance (D) in determining said parameter.
Claim 26
Dependent Claim
49 words
The method of claim 7, wherein said step of determining at least one of said power level (P), said beam diameter (B) and said scan rate (S) includes the step of using an equation having a form S=aB.sup.2 +bB+cP+dD+e where "a", "b", "c", "d", and "e" have predetermined values.
Claim 27
Dependent Claim
24 words
The method in accordance with claim 7, wherein said substrate comprises a printed circuit board, and said conductive plane comprises a voltage reference plane.
Claim 28
Dependent Claim
16 words
The method of claim 7, wherein said functional relationship is generally in the form: S=-1777.78B.sup.2 +113.89B+0.87P-191.43T+2.96.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1999-02-26 | 1999-08-28 | 2000-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2003-02-26 | 2003-08-28 | 2004-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2007-02-26 | 2007-08-28 | 2008-02-27 | $7700.00 | Window Closed / Lapsed |