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WO1999040591A1 - Technique d'ajustage par laser pour l'ablation de surface de composant resistif passif, dans laquelle un laser commute, solide et ultraviolet est utilise - Google Patents

Technique d'ajustage par laser pour l'ablation de surface de composant resistif passif, dans laquelle un laser commute, solide et ultraviolet est utilise Download PDF

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Publication number
WO1999040591A1
WO1999040591A1 PCT/US1998/017891 US9817891W WO9940591A1 WO 1999040591 A1 WO1999040591 A1 WO 1999040591A1 US 9817891 W US9817891 W US 9817891W WO 9940591 A1 WO9940591 A1 WO 9940591A1
Authority
WO
WIPO (PCT)
Prior art keywords
laser
resistor
area
exposed surface
film resistor
Prior art date
Application number
PCT/US1998/017891
Other languages
English (en)
Inventor
Yunlong Sun
Edward J. Swenson
Original Assignee
Electro Scientific Industries, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Electro Scientific Industries, Inc. filed Critical Electro Scientific Industries, Inc.
Publication of WO1999040591A1 publication Critical patent/WO1999040591A1/fr

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01C—RESISTORS
    • H01C17/00—Apparatus or processes specially adapted for manufacturing resistors
    • H01C17/22—Apparatus or processes specially adapted for manufacturing resistors adapted for trimming
    • H01C17/24—Apparatus or processes specially adapted for manufacturing resistors adapted for trimming by removing or adding resistive material
    • H01C17/242—Apparatus or processes specially adapted for manufacturing resistors adapted for trimming by removing or adding resistive material by laser

Definitions

  • the present invention relates to methods of laser trimming passive electrical components and, in particular, to a surface ablation method carried out with a Q-switched, solid-state ultraviolet (UV) wavelength laser to adjust the resistance value of a passive resistive component while mamtaining its power dissipation capacity or preserving its high frequency response characteristics.
  • a Q-switched, solid-state ultraviolet (UV) wavelength laser to adjust the resistance value of a passive resistive component while mamtaining its power dissipation capacity or preserving its high frequency response characteristics.
  • Fig. 1 A is an isometric view of a prior art thick-film resistor 10 forming part of a hybrid integrated circuit device, and Fig.
  • IB is a cross-sectional side elevation view depicting thick-film resistor 10 receiving a conventional laser output pulse 12.
  • a conventional thick-film resistor 10 typically comprises a thick film layer 14 of a ruthanate or ruthinium oxide material extending between and deposited on portions of the top surfaces of metallic contacts 16. Layer 14 and metallic contacts 16 are supported upon a ceramic substrate 18.
  • Modern ruthinium-based thick film pastes have been optimized to be stable after laser trimming with a 1.047 ⁇ m Nd.YLF laser or a 1.064 ⁇ m Nd : YAG laser .
  • the resistance value of resistor 10 is largely a function of the resistivity of the resistor material and its geometry, including length 22, width 24, and height 26. Because they are difficult to screen to precise tolerances, thick-film resistors are intentionally screened to lower than nomimal values and trimmed up to the desired values. Multiple resistors 10 having approximately the same resistance values are manufactured in relatively large batches and then subjected to trimming operations to remove incremental amounts of the resistor material until the resistance is increased to a desired value.
  • one or more laser pulses 12 remove substantially all of the resistor material within the spot dimensions 28 of laser output pulses 12.
  • a simple or complex pattern can be trimmed through the resistor material of a resistor 10 to fine tune its resistance value.
  • Fig. 2 is an isometric view of a portion of a prior art resistor 10 showing for convenience two common pattern trim paths 32 and 34 (separated by a broken line) between metal contacts 16.
  • "L-cut" path 32 depicts a typical laser-induced modification.
  • a first strip 36 of resistor material is removed in a direction perpendicular to a line between the contacts to make a coarse adjustment to the resistance value.
  • an adjoining second strip 38, perpendicular to the first strip 36 may be removed to make a finer adjustment to the resistance value.
  • a "serpentine cut” path 34 depicts another common type or laser adjustment. In a serpentine cut 34, resistor material is removed along strips 40 to increase the length of path 42.
  • Strips 40 are added until a desired resistance value is reached. Strips 36, 38, and 40 represent the cumulative "nibbling" of a train of overlapping laser pulses 12 that remove nearly all of the resistor material within the prescribed patterns. Thus, the substrate 18 underlying the resistor material is completely exposed when the trimming operation is completed.
  • L-cuts 32 and serpentine cuts 34 reduce the surface area of a resistor and its area of contact with the substrate and thus reduce the ability of the resistor to dissipate heat to the air above or to the substrate below. For this reason, many thick-film power resistors are trimmed using abrasive trimmers to remove only the top surface to adjust the resistance value. The abrasive trimming technique is neither clean nor fast.
  • An object of the present invention is, therefore, to provide a method of laser trimming a passive resistive component to change its resistance value while leaving substantially unchanged coverage of the substrate area the component occupies to maintain its power dissipation capacity or preserve its high frequency response characteristics.
  • the output of a 266 nm or 355 nm, Q-switched YAG laser or a 349 nm, Q-switched YLF laser is controlled so that no single output pulse completely removes thick-film resistor material depthwise at any given location.
  • the laser output is moved in a line scan or raster scan fashion across an area of the resistor material to ablate a portion of its surface area to a depth that is less than the height of the resistor material.
  • UV laser output trimming transmits better the UV energy through the trimming-generated plasma plume over the resistor surface into metal-based resistive materials and couples better the UV energy to create a much smaller heat- affected zone. The result is a much sharper cut off at the transition between the removed and remaining volumes of resistor material in the lateral and depthwise directions after surface ablation of a resistor.
  • Varying the laser fluence, scan speed, bite size, repetition rate, and pitch makes possible the control of the amount of material, and particularly the depth of material, removed by the laser, and thus increases the resistance of the resistor to a desired value. Partly removing the resistor material allows resistance tuning with no damage to the substrate. Leaving substantially unchanged the substrate area the resistor covers maintains its power dissipation capacity and preserves its frequency response characteristics.
  • An advantage of using a UV laser wavelength such as 355 nm allows the spot size of the laser output to be almost three times smaller (e.g., 7 ⁇ m for thick film targets) than a conventional 1.064 ⁇ m laser output spot for both conventional pattern trimming and the new surface trimming technique. This facilitates achieving more precise resistor values and enables trimming of smaller devices.
  • Fig. 1A is a fragmentary isometric view of a thick-film resistor.
  • Fig. IB is a cross-sectional side view of a thick-film resistor receiving laser output that removes the full thickness of resistor material.
  • Fig. 2 is a fragmentary isometric view of a resistor showing two common prior art trim paths.
  • Fig. 3 is a partly schematic, simplified diagram of a laser system adapted for performing the surface ablation technique of the present invention.
  • Fig. 4 A is an isometric view of a thick-film resistor with a trim profile in accordance with one embodiment of the present invention.
  • Fig. 4B is a cross-sectional side view of the thick-film resistor shown in Fig. 4A.
  • Fig. 5 is an isometric view of a thick-film resistor with a trim profile in accordance with a first alternative embodiment of the present invention.
  • Fig. 6 is an isometric view of a thick-film resistor with a trim profile in accordance with a second alternative embodiment of the present invention.
  • Figs. 7 A and 7B are isometric views of resistor material in which multiple recesses and multiple thin grooves, respectively, are inscribed to trim the resistance value of the resistor material.
  • Fig. 3 shows an embodiment of a simplified laser system 50 for generating preferred laser pulses that satisfy the energy distributions desirable for achieving surface ablation in accordance with the present invention.
  • laser system 50 is modeled herein only by way of example as a diode-pumped third harmonic Nd:YAG laser (355 nm).
  • Laser system 50 includes a resonator 52 having a laser module 54 positioned between a highly reflective mirror 56 and an output coupler 58 along an optic axis 60.
  • Laser module 54 is preferably a X-30 laser head module manufactured by Spectra Physics Lasers of Mountain View, California, that has been modified to have its resonator mirrors removed.
  • Laser module 54 contains an Nd:YAG lasant rod that is pumped by two 20 W FCb ⁇ rTM diode lasers 62 supported by a T-40 laser power supply 64, all manufactured by Spectra Physics Lasers.
  • Mirror 56 is preferably 100 percent reflective
  • coupler 58 is about 99.98% reflective at 1064 nm, about 99% reflective at 532 nm, and about 90% transmissive at 355 nm to light propagating along optic axis 60.
  • Other preferred lasers include a third harmonic Nd:YLF (349 nm) and a fourth harmonic Nd:YAG (266 nm).
  • a third harmonic Nd:YLF 349 nm
  • a fourth harmonic Nd:YAG 266 nm
  • Skilled persons will appreciate that other suitable solid-state lasers emitting at wavelengths below 400 nm are commercially available and could be employed.
  • the UV wavelengths can be employed to produce practical ablation spot sizes that are significantly less than about 20 to 30 ⁇ m for thick film targets. These parameters are affected by target accessibility constraints such as the position of probes and surrounding electronic circuitry.
  • a laser system of the Models 44, 4000, 4200, 4300, and 4410, manufactured by Electro Scientific Industries, Inc. in Portland, Oregon, is preferred and could be adapted by skilled persons to emit light energy at any of these wavelengths.
  • Laser system output 80 can be manipulated by a variety of conventional optical elements including beam expander lens components 82 and 84 that are positioned along a beam path 86. Finally, laser system output 80 is passed through a focusing or imaging lens 88 before being applied to a laser target position 90 on a resistor 92 (Figs. 4 A and 4B).
  • a beam positioning system 94 preferably operates in association with a laser controller 96 that controls the motion of an X-Y positioner to target and focus laser system output 80 to a desired laser target position 90 on resistor material 112 (Figs. 4 A and 4B). Beam positioning system 94 permits quick movement of output 80 along target positions 90 on the same or different resistors to effect unique trimming operations based on predetermining calculations or provided test data.
  • a preferred beam positioning system 94 is a galvanometer-based beam positioner with 4" x 4" (100 mm x 100 mm) field coverage.
  • a positioning command data base associated with controller 96 stores commands that direct the path of laser system output 80 so that it strikes the desired target positions 90.
  • laser controller 96 may process timing data that synchronizes the firing of laser system 50 to positioning stage motion as described in U.S. Patent No. 5,453,594 of Konecny for Radiation Beam Position and Emission Coordination System.
  • Laser controller 96 determines the amplitude of preselected or variable RF oscillator signals delivered to an acoustic wave transducer of Q-switch 104.
  • Laser controller 96 may be used to deliver laser output pulses having about 10 ns to 100 ns duration at about 1 to 5 kHz, preferably 30 ns at 5 kHz.
  • Figs. 4A and 4B are respective isometric and side elevation views of a thick-film resistor 92 after it has been trimmed to a desired resistance value in accordance with the present invention.
  • resistor 92 includes a resistor material 112 layered upon a ceramic or glass substrate 114a and contacting electrodes 116.
  • Resistor material 112 has a geometry that includes a length 122, widths 124a and 124b, and heights 126a and 126b that determine the volume and cross-sectional areas of resistor material 112.
  • the " geometry of resistor material 112 determines its resistance value and greatly influences the power dissipation capacity of resistor 92 and its frequency response.
  • Length 122, width 124b, and depth 126c dimensions define a trim profile such as surface ablation area 130 that can be removed by raster or line scanning multiple pulses of laser output 80 across resistor material 112.
  • a trim profile such as surface ablation area 130 that can be removed by raster or line scanning multiple pulses of laser output 80 across resistor material 112.
  • surface ablation area 130 is determined on-the-fly by the incremental nibbling of laser output pulses 80, such that each laser output pulse 80 removes a minute amount of the surface of resistor material 112 to slightly increase the resistance value of resistor 92. Laser output pulses 80 are applied until resistor 110 meets a predetermined resistance value.
  • Fig. 5 shows a resistor 140 after it has been trimmed with a first alternative trim profile such as a surface ablation area 142.
  • a first alternative trim profile such as a surface ablation area 142.
  • resistor 140 For convenience, certain features of resistor 140 that correspond to features of resistor 92 in Fig. 4 have been designated with the same reference numerals.
  • surface ablation area 142 is also removed by the surface ablation technique, described in connection with Fig. 4, so that the entire height 126a of resistor material 112 within surface ablation area 142 is not removed.
  • Surface ablation area 142 does not extend completely between edges 132 so laser output 80 can completely avoid exposure of substrate 114b.
  • Fig. 6 shows a resistor 150 after it has been trimmed with a second alternative trim profile such as a surface ablation area 152.
  • Surface ablation area 152 is also removed by the surface ablation technique previously described.
  • certain features of resistor 150 that correspond to features 92 of Fig. 4 have been designated with the same reference numerals.
  • surface ablation area 152 extends over, but does not remove the full height 126a of resistor material above, electrode 116 so that it is free from exposure to laser " output 80.
  • Figs. 7A and 7B show isometric views of resistor material 112 in which two exemplary discontinuous trim profiles embodying the present invention are inscribed to trim the resistance value of resistor material 112.
  • a resistor 160 has an array of spaced-apart circular recesses 162 that do not extend depthwise into the full height of resistor material 112. Recesses 162 represent punch marks each of which is about the ablation spot size of the UV laser and which together form a composite surface ablation area 164.
  • a resistor 170 has an array of mutually spaced apart, thin groove lines 172 extending in the direction of electrical current flow between electrodes 116. Adjacent groove lines 172 can be spaced very close to each other and together form a composite surface ablation area 174. Like recesses 162, groove lines 172 do not extend depthwise into the full height of resistor material 112. With reference to Figs.
  • a laser output 80 that can be used to form surface ablation areas 132, 142, 152, 164, and 174 for high precision trimming of thick-film resistors includes individual laser output pulses at a power of about 5 mW, a repetition rate of about 1 kHz, a scan speed of about 9 mm/sec, and bite sizes of about 6 ⁇ m or 9 ⁇ m. More general laser output pulse parameters include power ranges of between about 10 mW and 50 mW, repetition rates of greater than about 300 Hz, scan speeds of between about 3 mm/sec and 300 mm/sec, and bite sizes selected in accordance with the accuracy, resolution, and throughput required.
  • the surface ablation technique of the present invention does not reduce the amount of resistor material 92 in contact with substrate 114 (114a or 114b). Thus, the ability of resistors 92, 140, 150, 160, or 170 to dissipate heat to substrate 114 is not significantly affected. Similarly, the surface ablation technique of the present invention preserves the total surface areas of resistors 92, 140, 150, 160, or 170 and minimizes the creation of sources of unpredictable high frequency responses in resistors 92, 140, 150, 160, or 170.
  • a consequence of using a UV laser is the creation of a relatively small heat-affected zone (as compared with that produced by 1.047 ⁇ m and 1.064 ⁇ m laser trimming) that results in higher accuracy trimming.
  • resistors 92, 140, 150, 160, and 170 portrayed in Figs. 4A, 4B, 5, 6, 7 A, and 7B can be trimmed to tolerances that are tighter than the tolerances possible for conventional full-height kerf trimming techniques.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Plasma & Fusion (AREA)
  • Manufacturing & Machinery (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Apparatuses And Processes For Manufacturing Resistors (AREA)

Abstract

L'invention concerne un procédé d'ajustage par laser, d'un composant passif résistif, dans lequel on modifie la valeur de résistance de ce dernier et on maintient sensiblement inchangée la zone de couverture occupée par la zone de substrat, afin de maintenir la capacité de dissipation d'énergie du composant et de conserver ses caractéristiques de réponse en haute fréquence. Dans un mode de réalisation préféré, on module la sortie d'un laser YAG déclenché de 266 ou 355 nm, ou d'un laser YLF déclenché de 349 nm, de sorte qu'aucune impulsion de sortie n'enlève complètement le matériau de la résistance à couche épaisse, en un emplacement donné. On déplace la sortie laser en balayage en ligne ou récurrent, sur une zone du matériau de la résistance, pour enlever une partie de la surface de ce dernier, jusqu'à une profondeur qui est inférieure à la hauteur du matériau formant la résistance. La modification de la fluence, de la vitesse de balayage, de l'ampleur de la morsure, de la fréquence de répétition et du pas du laser, permet de moduler la quantité de matériau, et notamment l'épaisseur de matériau, enlevée par le laser. On déplace en balayage la sortie sur la surface exposée de la résistance, jusqu'à ce que la valeur de résistance atteigne une valeur voulue. L'enlèvement partiel du matériau formant la résistance, permet la syntonisation de la résistance sans que le substrat soit endommagé. Le fait de laisser sensiblement inchangée la zone du substrat recouverte par la résistance, permet le maintien de sa capacité de dissipation d'énergie et la préservation de ses caractéristiques de réponse en fréquence.
PCT/US1998/017891 1998-02-06 1998-08-28 Technique d'ajustage par laser pour l'ablation de surface de composant resistif passif, dans laquelle un laser commute, solide et ultraviolet est utilise WO1999040591A1 (fr)

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US2031098A 1998-02-06 1998-02-06
US09/020,310 1998-02-06

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6534743B2 (en) 2001-02-01 2003-03-18 Electro Scientific Industries, Inc. Resistor trimming with small uniform spot from solid-state UV laser
US6951995B2 (en) 2002-03-27 2005-10-04 Gsi Lumonics Corp. Method and system for high-speed, precise micromachining an array of devices
KR100894025B1 (ko) * 2001-02-01 2009-04-22 일렉트로 싸이언티픽 인더스트리이즈 인코포레이티드 고체-상태 ｕｖ 레이저로부터의 작은 균일한 스폿을 이용한 저항기 트리밍을 위한 방법
US7563695B2 (en) 2002-03-27 2009-07-21 Gsi Group Corporation Method and system for high-speed precise laser trimming and scan lens for use therein
CN107895619A (zh) * 2017-12-28 2018-04-10 深圳市杰普特光电股份有限公司 贴片电阻激光调阻系统
EP3349223A4 (fr) * 2015-10-15 2019-06-05 Suncall Corporation Procédé de fabrication de résistance de shunt
US10418157B2 (en) 2015-10-30 2019-09-17 Vishay Dale Electronics, Llc Surface mount resistors and methods of manufacturing same
US10438729B2 (en) 2017-11-10 2019-10-08 Vishay Dale Electronics, Llc Resistor with upper surface heat dissipation
CN120199566A (zh) * 2025-05-23 2025-06-24 长春长光辰星科技有限公司 基于云平台的调阻机设备集群运行状态管理方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2131356A1 (de) * 1971-06-24 1972-12-28 Rohde & Schwarz Verfahren zum Trimmen von in Duenn- oder Dickschichttechnik hergestellten elektrischen Widerstaenden
WO1988002183A1 (fr) * 1986-09-19 1988-03-24 Hughes Aircraft Company Ebarbage de composants passifs noyes dans des structures multicouches
US5453594A (en) * 1993-10-06 1995-09-26 Electro Scientific Industries, Inc. Radiation beam position and emission coordination system
US5685995A (en) * 1994-11-22 1997-11-11 Electro Scientific Industries, Inc. Method for laser functional trimming of films and devices

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2131356A1 (de) * 1971-06-24 1972-12-28 Rohde & Schwarz Verfahren zum Trimmen von in Duenn- oder Dickschichttechnik hergestellten elektrischen Widerstaenden
WO1988002183A1 (fr) * 1986-09-19 1988-03-24 Hughes Aircraft Company Ebarbage de composants passifs noyes dans des structures multicouches
US5453594A (en) * 1993-10-06 1995-09-26 Electro Scientific Industries, Inc. Radiation beam position and emission coordination system
US5685995A (en) * 1994-11-22 1997-11-11 Electro Scientific Industries, Inc. Method for laser functional trimming of films and devices

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
GOFUKU E ET AL: "RESISTANCE ADJUSTMENT WITH SHORT-PULSE ND:YAG LASER FOR RUO2-BASED THICK-FILM RESISTORS BURIED IN POLYIMIDE FILM", IEEE TRANSACTIONS ON COMPONENTS,HYBRIDS,AND MANUFACTURING TECHNOLOGY, vol. 16, no. 6, 1 September 1993 (1993-09-01), pages 592 - 597, XP000412761 *

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6534743B2 (en) 2001-02-01 2003-03-18 Electro Scientific Industries, Inc. Resistor trimming with small uniform spot from solid-state UV laser
KR100894025B1 (ko) * 2001-02-01 2009-04-22 일렉트로 싸이언티픽 인더스트리이즈 인코포레이티드 고체-상태 ｕｖ 레이저로부터의 작은 균일한 스폿을 이용한 저항기 트리밍을 위한 방법
DE10295946B4 (de) * 2001-02-01 2013-09-26 Electro Scientific Industries, Inc. Verfahren zum Lasertrimmen eines Schichtwiderstandes
US6951995B2 (en) 2002-03-27 2005-10-04 Gsi Lumonics Corp. Method and system for high-speed, precise micromachining an array of devices
US7407861B2 (en) 2002-03-27 2008-08-05 Gsi Group Corporation Method and system for high-speed, precise micromachining an array of devices
US7563695B2 (en) 2002-03-27 2009-07-21 Gsi Group Corporation Method and system for high-speed precise laser trimming and scan lens for use therein
EP3349223A4 (fr) * 2015-10-15 2019-06-05 Suncall Corporation Procédé de fabrication de résistance de shunt
US10418157B2 (en) 2015-10-30 2019-09-17 Vishay Dale Electronics, Llc Surface mount resistors and methods of manufacturing same
US10438729B2 (en) 2017-11-10 2019-10-08 Vishay Dale Electronics, Llc Resistor with upper surface heat dissipation
CN107895619A (zh) * 2017-12-28 2018-04-10 深圳市杰普特光电股份有限公司 贴片电阻激光调阻系统
CN107895619B (zh) * 2017-12-28 2024-04-30 深圳市杰普特光电股份有限公司 贴片电阻激光调阻系统
CN120199566A (zh) * 2025-05-23 2025-06-24 长春长光辰星科技有限公司 基于云平台的调阻机设备集群运行状态管理方法

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