JP4846282B2 - Electronic component package sealing method and apparatus - Google Patents

Description

  The present invention relates to an electronic component package sealing technique in which a package body is covered with an upper lid or a cover, and more particularly to an electronic component package sealing method and apparatus using laser welding.

  2. Description of the Related Art An electronic component package that is hermetically sealed by covering an upper lid or cover on a package body is used for, for example, a surface-mount type crystal resonator. As shown in FIG. 13, the metal package body 10 is formed as a rectangular shallow container having an open top surface, and accommodates the crystal piece 12 and the electrode 14 therein. The electronic component package 18 can be sealed by covering the package body 10 with a metal cover 16 from above and airtightly bonding the cover 16. The material of the package body 10 and the cover 16 is, for example, steel plated with nickel. Conventionally, gold-tin sealing, seam welding, and the like have been used as this type of sealing method.

Among these, when using the conventional laser seam welding method, as shown in FIGS. 14 and 15, a method of overlapping the pulsed laser light LB is employed. That is, the irradiation position or beam spot of the pulse laser beam LB on the workpiece 18 (10, 16) is scanned by a scanning mechanism such as an XY table while irradiating the peripheral end portion of the cover 16 with the pulse laser beam LB obtained by repeated pulse oscillation. Relative step movement at a constant pitch, and spot welding points..., W _i , W _{i + 1} , W _{i + 2} ,. A continuous weld WB is formed. FIG. 16 shows the waveform of the pulsed laser beam LB in this laser seam welding. T _a is the pulse width of one pulse, T _b is the period of one pulse, and T _c is the seam welding time (sealing time).

As an example, when the size of the cover 16 is 2 mm × 4 mm, if the spot diameter or bead width is set to 0.2 mm, the overlap rate is set to 50%, and the pulse frequency (1 / T _b ) is set to 100 pps, The number of laser shots [N] is 120, and the seam welding time (sealing time) T _c is 1.2 seconds.

However, in the conventional laser seam welding method as described above, the beam spots of the pulse laser beam LB,..., W _i , W _{i + 1} , W _{i + 2} ,. Since it is a welding process for making a round of the peripheral end of the cover 16, not only the processing time is long and the productivity is low, but also heat is trapped in the electronic component package 18 during the processing, and the element (crystal piece) 12 Could be damaged by heat. In particular, the laser scanning path bends at right angles at the corners of the cover 16, so that there is a tendency that the number of laser spots or shots is concentrated and heat storage further increases, and sealing processing is performed in the circumferential direction of the cover 16. It was difficult to make uniform.

  In addition, the seam welding by the CW laser has a laser output (power density) of the CW laser beam that is remarkably lower (by orders of magnitude) compared to the laser output of the pulse laser beam, which is more than the overlap type spot welding method as described above. However, since the welding speed is slow and heat is easily generated, it is not suitable for sealing an electronic component package.

  The present invention has been made in view of the above-described problems of the prior art, has a short processing time, has a small thermal effect on the elements in the package during processing, and has high reproducibility and uniform sealing. An object of the present invention is to provide an electronic component package sealing method and an electronic component package sealing device capable of processing.

In order to achieve the above object, a first electronic component package sealing method of the present invention seals an electronic component package by airtightly joining the peripheral end portion of a cover placed on a package body having an open top surface. A pulse laser device that oscillates and outputs a pulse laser beam having a predetermined pulse period and simultaneously controls a galvanometer scanner so that a beam spot of the pulse laser beam is generated during the pulse period. The peripheral edge of the cover is scanned and irradiated with the pulsed laser light from above, so that the peripheral edge of the cover is joined to the package body by seam welding over the entire circumference. .

The first electronic component package sealing apparatus of the present invention is an electronic component package sealing device that seals an electronic component package by hermetically joining the peripheral end portions of the cover that covers the package main body having an open top surface. A pulse laser oscillation unit that includes a laser medium and an excitation light source that optically excites the laser medium, and oscillates and outputs pulsed laser light having a laser output corresponding to the power supplied to the excitation light source. And a scan mirror for reflecting the pulsed laser light from the pulsed laser oscillating unit toward the peripheral end of the cover on the package body, and the pulse to the peripheral end of the cover and galvanometer scanner for moving the beam spot of the laser beam in a predetermined path, the laser output of said generated from the pulsed laser oscillator part and the pulsed laser beam A laser output measuring unit for constant laser output measured value obtained from the laser output measuring unit is desired laser output setting value or the laser power supply unit for supplying power to the excitation light source of the pulsed laser oscillator part so as to match the waveform The pulse laser beam of one pulse generated from the pulse laser oscillation unit is irradiated to the peripheral end portion of the cover, and the beam spot of the pulse laser beam makes a round around the peripheral end portion of the cover during one pulse period. as to, and a control unit for controlling in cooperation with said galvanometer scanner and the laser power supply unit at the same time.

In the above configuration, the cover placed on the package body is obtained by simultaneously coordinating the laser oscillation output operation of one pulse by the pulse laser device (or the pulse laser oscillating unit) and the scan mirror swing operation of the galvanometer scanner. A pulse laser beam of one pulse is irradiated on the peripheral edge of the cover, and the beam spot of the pulse laser light makes a round around the cover peripheral edge during one pulse period. At each position where the pulse laser beam is irradiated, the joint portion of the cover and the main body is instantaneously welded by the laser energy. During one pulse period, the beam spot of the pulse laser beam scans and moves without stopping, stopping or interrupting even for a moment, and a seam weld is formed on the trace through which the beam spot has passed as if it were a single stroke . In order to obtain a high-power pulse laser beam, it is preferable to use a YAG pulse laser.

According to a preferred aspect of the present invention, the beam spot of the pulsed laser light makes a round around the peripheral edge of the cover at a substantially constant speed, and maintains a substantially constant laser output during this period. The uniformity of laser seam welding or sealing processing can be further improved by such constant-speed laser scanning and further by constant-power laser scanning.

In the first electronic component package sealing apparatus, according to a preferred aspect, the laser power source unit stores a bank capacitor for storing power supplied to the excitation light source of the pulse laser oscillation unit, and the bank capacitor is preliminarily disposed. A charging circuit that charges a set charging voltage, and a power supply control unit that controls the switching element so that the comparison error is zero by comparing the laser output measurement value from the laser output measurement unit with the laser output setting value or waveform. Are connected in parallel to the pulse laser oscillation unit, and the plurality of laser power supply circuits are sequentially switched at a predetermined timing during one pulse period, and the pulse laser oscillation unit continues for one pulse period. Supply a pulsed current with time. According to the bank switching method having such a configuration, it is possible to generate pulse laser light having a very long pulse width (ultra-long pulse) by power feedback waveform control.

The second electronic component package sealing process of the present invention is a method for sealing an electronic component package by bonding a peripheral edge portion of the square cover placed over the package body which is open on the upper surface in an air-tight, pulsed laser The apparatus oscillates and outputs the first pulse laser beam having one pulse having the first pulse period, and simultaneously controls the galvanometer scanner so that the beam spot of the first pulse laser beam during the first pulse period. So that the first pulse laser beam is scanned from above the first side of the cover so that the first side of the cover crosses the first side of the cover. wherein a first step of joining seam welded to the package body, the second pulse laser beam of one pulse having a second pulse duration to the pulse laser apparatus when the oscillation output at the same time The galvanometer scanner is controlled so that a beam spot of the second pulse laser beam vertically cuts the second side of the cover during the second pulse period. a second step of the above said second pulse laser beam scanning irradiation from joining the peripheral edge portion of the cover at the seam welded to the package body at said second side, first in the pulsed laser apparatus The third pulse laser beam having one pulse period is oscillated and output, and at the same time, the galvanometer scanner is controlled so that the beam spot of the third pulse laser beam is changed during the third pulse period. to cross the third side of the cover, the above from above to the third side of the cover the third scan pulse laser beam irradiation, said peripheral edge portion of the cover first Third step and the fourth pulse the fourth time the galvanometer scanner when the oscillated output a pulse laser beam having a pulse duration to the pulse laser apparatus to at sides joined at seam welded to said package body To control the fourth side of the cover from above so that the beam spot of the fourth pulse laser beam cuts through the fourth side of the cover during the fourth pulse period. A fourth step of scanning and irradiating a fourth pulse laser beam, and joining the peripheral end of the cover to the package body at the fourth side by seam welding.

Further, the second electronic component package sealing apparatus of the present invention is an electronic component package sealing device that seals the electronic component package by hermetically bonding the peripheral end portion of the quadrangular cover that covers the package main body having an open top surface. an apparatus comprising: a laser medium, and a pump light source that pumps the laser medium optically, pulsed laser oscillation of the pulsed laser light oscillation output having a laser output corresponding to the power supplied to the excitation light source And a scan mirror for reflecting the pulsed laser light from the pulsed laser oscillation unit toward the peripheral end of the cover on the package body, and with respect to the peripheral end of the cover and galvanometer scanner for moving the beam spot of the pulsed laser beam in a predetermined path, the laser generated from the pulsed laser oscillator part and the pulsed laser beam A laser output measuring unit for measuring the force, the laser supplies power to the excitation light source of the pulsed laser oscillator part as the laser output measured value obtained from the laser output measuring unit matches the desired laser output set value or waveform Four pulse laser beams continuously generated from the power supply unit and the pulse laser oscillation unit with a desired interval between them are irradiated to the four peripheral edges of the cover, and the beam spot of each pulse laser beam is A control unit that controls the laser power supply unit and the galvanometer scanner in cooperation with each other so as to cut through the corresponding sides of the cover during one pulse period;

In the above-described configuration, the one-pulse laser oscillation output operation by the pulse laser device (or the pulse laser oscillation unit) and the scan / mirror swing operation of the galvanometer / scanner simultaneously cooperate with each other to form a quadrangle placed on the package body. Each side of the cover is irradiated with one pulse of pulsed laser light, and the beam spot of the pulsed laser light cuts through each side of the cover during one pulse period. At each position where each pulse laser beam is irradiated, the joint portion of the cover and the main body is instantaneously welded by the laser energy. During one pulse period, the beam spot of the pulsed laser beam does not stop, stop or stop even for a moment, and it moves without changing the direction of the path, and the seam weld is formed in a straight line at the trace where the beam spot passes. The According to this method, it is not necessary to change or bend the moving direction of the laser beam spot at the corner of the cover, that is, at the start and end of each side of the cover. Welding joints can be obtained. Also in this method, it is preferable that the beam spot of the pulsed laser beam cuts each side of the cover at a substantially constant speed, and a substantially constant laser output may be maintained during this period.

  Preferably, on the four sides of the cover, the end of the second side is connected to the end of the first side, the start of the third side is connected to the end of the second side, and the end of the third side is connected. An order relationship may be set such that the beginning of the fourth side is connected to the first end, and the end of the fourth side is connected to the starting end of the first side. Further, intervals without pulse laser light are provided between the first step and the second step, between the second step and the third step, and between the third step and the fourth step, respectively. May be.

The method smell Te, preferably, may move the virtual beam spot without pulsed laser light outside the region of the cover by galvanometer scanner during each interval. In one preferred embodiment, the movement locus of the virtual beam spot is the first straight line from the end of one side of the cover that has been seam welded in the immediately preceding process to the first folding point that is a predetermined distance away from the extension. A second straight path from the first turn point to a second turn point that is a predetermined distance away from the starting end of one side of the cover to be seam welded in the next step; A third straight path from the second turning point to the start of one side of the cover to be seam welded in the next step.

  According to a preferred aspect of the electronic component package sealing method of the present invention, one or more selected peripheral portions of the cover are subjected to seam welding processing of the peripheral portion of the cover to the package body. Spot welding for temporary fixing is performed by locally irradiating the portions with pulsed laser beams. In this case, the same pulse laser device can be used for spot welding for temporary fixing and seam welding for sealing.

  According to the electronic component package sealing method or apparatus of the present invention, due to the above-described configuration and operation, the sealing processing time is significantly shortened, and the elements in the package are thermally affected during processing. Without any problem, uniform sealing with high productivity and reproducibility can be performed.

  Hereinafter, preferred embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 shows an overall configuration of an electronic component package sealing apparatus according to an embodiment of the present invention. The electronic component package sealing apparatus includes a YAG pulse laser apparatus 20, a laser optical system 22, and a main control unit 24 as main components. Here, the YAG pulse laser device 20 is configured to oscillate and output an ultra long pulse (generally, 50 milliseconds or more) YAG pulse laser light LA under the control of the main control unit 24. The laser optical system 22 is a scanning optical system, and transmits the pulsed laser light LA received from the YAG pulse laser device 20 to the incident unit 26 to the galvanometer scanner 30 through the optical fiber 28, as will be described later. Under the control of the control unit 24 and the scanner control unit 32, the galvanometer scanner 30 scans and irradiates the peripheral end portion of the cover 16 of the electronic component package 10 with the pulsed laser light LA. The main control unit 24 may be composed of a microcomputer.

  FIG. 2 shows an internal configuration of the YAG pulse laser device 20. The YAG pulse laser device 20 includes a YAG laser oscillator 34, a plurality of, for example, three laser power supply circuits 36A, 36B, and 36C connected in parallel to the YAG laser oscillator 34, and a YAG output from the YAG laser oscillator 34. And a laser output measuring unit 38 for measuring the laser output of the pulsed laser beam LA, and is configured so that the waveform of the laser output of the YAG pulsed laser beam LA can be arbitrarily controlled by a power feedback control method.

  The YAG laser oscillator 34 is disposed on the optical axis of the YAG rod 44 outside the chamber 40 and a pumping light source 42 composed of an excitation lamp or a semiconductor laser disposed in the chamber 40 and a YAG rod 44 as a laser medium. A pair of optical resonator mirrors 46 and 48 is provided. In the chamber 40, the excitation light source 42 and the YAG rod 44 are temperature-controlled by a cooling medium such as cooling water circulated and supplied from a cooling unit (not shown) outside the chamber. When the excitation light source 42 emits pulses and emits excitation light, the YAG rod 44 is excited by the energy of the excitation light, and the light emitted from the both end surfaces of the YAG rod 44 on the optical axis is the optical resonator mirrors 46 and 48. After being reflected and amplified repeatedly, the laser beam exits the output mirror 48 as pulsed laser light LA. The pulse laser beam LA that has escaped from the output mirror 48 is sent to the galvanometer scanner 30 (FIG. 1) of the laser optical system 22.

  The laser output measuring unit 38 is based on a photosensor that receives the laser beam LA ′ leaked behind the total reflection mirror 46 in the optical resonator mirrors 46 and 48 of the laser oscillator 40 and an electric signal output from the photosensor. And a measurement circuit for measuring the laser output of the pulsed laser beam LA, and a laser output measurement value signal ML obtained from the measurement circuit is used as a feedback signal to control the power supply of each of the laser power supply circuits 36A, 36B, 36C described later It gives to part 52A, 52B, 52C.

  The laser power supply circuit 36A includes a bank capacitor 50A for accumulating laser oscillation power to be supplied to the excitation light source 42 of the laser oscillator 40, and a switching element 52A connected between the bank capacitor 50A and the excitation light source 42. A charging circuit 54A for charging the bank capacitor 52A, and a power supply control unit 56A for controlling each part in the power supply circuit, particularly the switching element 52A and the charging circuit 54A.

Switching element 52A is made of, for example, a power transistor or IGBT (insulated gate bipolar transistor), and is turned on / off in response to a switching control signal SC of high frequency (for example, 20 kHz) supplied from power supply control unit 56A through drive circuit 66A. It is supposed to turn off. An excitation current supply circuit including an inductance coil 60A, a flywheel diode 62A, and a backflow prevention diode 64A is provided between the switching element 52A and the excitation light source 42. When the switching element 52A is turned on, an excitation current I _RA flows in a closed circuit including the bank capacitor 50A, the switching element 52A, the inductance coil 60A, the backflow prevention diode 64A, and the excitation light source 42. That is, the energy stored in the capacitor 50A is supplied to the excitation light source 42 as a discharge current. When the switching element 52A is turned off, the excitation current I _RA flows in a closed circuit including the flywheel diode 62A, the inductance coil 60A, the backflow prevention diode 64A, and the excitation light source 42. That is, the energy accumulated in the inductance coil 60A is supplied to the excitation light source 42 as a reflux current.

  The charging circuit 54A converts commercial alternating current, for example, three-phase alternating current power supply voltage (U, V, W) into direct current to charge the bank capacitor 50A to a predetermined direct current voltage. Includes switching elements and the like.

Power control unit 56 A, as the laser output measurement value ML obtained from the laser output measuring unit 38 coincides or follows the reference value signal KSA corresponding to the laser output set value or waveform, the switching of the switching element 52A (on OFF) Has the function of controlling the operation. That is, in order to perform feedback-type laser power waveform control, the power supply control unit 52A compares the laser output measurement value ML from the laser output measurement unit 38 with the reference signal KSA from the main control unit 24, and responds to the comparison error. The PWM switching control signal SC is generated.

The other laser power supply circuits 36B and 36C also have the same circuit configuration as the laser power supply circuit 36A, and the laser output measurement values from the laser output measurement unit 38 are added to the reference signals KSB and KSC from the main control unit 24, respectively. The pumping light sources 42 are supplied with pumping currents I _RB and I _RC by operating so that the MLs match or follow.

The main controller 24 operates the three laser power supply circuits 36A, 36B, and 36C by switching them sequentially or alternately. More specifically, as shown in FIG. 3, the period T _{S of} one pulse is divided into three sections, and the first section (t _{0 to} t ₁ ) is supplied to the laser power supply circuit 36A (bank A) as a reference value signal. KSA is applied to supply the excitation current I _RA from the bank A to the excitation light source 42, and in the second section (t _{1 to} t ₂ ), the reference value signal KSB is applied to the laser power supply circuit 36B (bank B) from the bank B. The excitation current I _RB is supplied to the excitation light source 42, and in the third or last section (t _{2 to} t ₃ ), the reference value signal KSC is supplied to the laser power supply circuit 36C (bank C) to supply the excitation current I _RC from the bank C. To the excitation light source 42. The YAG pulse laser apparatus 20 of this embodiment can generate the ultra long pulse YAG pulse laser beam LA by the power feedback waveform control by the bank switching method as described above.

  FIG. 4 shows a configuration example of the galvanometer scanner 30. The galvanometer scanner 30 includes an X-axis scan mirror 70X and a Y-axis scan mirror 70Y mounted on rotation axes 68X and 68Y orthogonal to each other, and an X-axis for rotating and vibrating (oscillating) both mirrors 70X and 70Y. It has a galvanometer 72X and a Y-axis galvanometer 72Y.

  The pulse laser beam LA emitted radially from the end face of the optical fiber 28 is converted into a parallel light beam by the collimator lens 74 and first enters the X-axis scan mirror 70X, where it is totally reflected and then applied to the Y-axis scan mirror 70Y. Incident light is totally reflected by the mirror 70Y, passes through the fθ lens 76, and is condensed on a processing point (cover peripheral edge) of the workpiece (electronic component package 18). The irradiation position of the pulse laser beam LA on the workpiece 18 is determined by the swing angle of the X-axis scan mirror 70X in the X direction, and is determined by the swing angle of the Y-axis scan mirror 70Y in the Y direction. The X-axis scan mirror 70X rotates (oscillates) in the directions of arrows A and A 'by driving the X-axis galvanometer 72X, and the Y-axis scan mirror 70Y in the directions of arrows B and B' by driving the Y-axis galvanometer 72Y. It is designed to rotate (swing). The fθ lens 76 is constituted by, for example, a combined lens of a telecentric optical system.

  The X-axis galvanometer 72X has, for example, a movable iron piece (rotor) coupled to the X-axis scan mirror 70X, a control spring connected to the movable iron piece, and a drive coil attached to the stator. Yes. A drive current corresponding to the X-direction scanning control signal is supplied from the scanner control unit 32 to the drive coil in the X-axis galvanometer 72X via the electric cable 78X, and the movable iron piece (rotor) resists the control spring. The X-axis scanning mirror 70X is integrated with the X-direction scanning control signal at an angle specified by the X-axis scanning mirror 70X.

  The Y-axis galvanometer 72Y has the same configuration, and the drive current corresponding to the Y-direction scanning control signal is supplied from the scanner control unit 32 to the drive coil in the Y-axis galvanometer 72Y via the electric cable 78Y. The movable iron piece (rotor) in the shaft galvanometer 72Y is swung at an angle specified by the Y-direction scanning control signal integrally with the Y-axis scanning mirror 70Y.

  The electronic component package 18 as a workpiece is the same as that shown in FIG. 11, for example, and a metal cover is attached to the metal package body 10 having an open top surface that accommodates the crystal piece 12 and the electrode 14. This type is sealed by covering 16 from above and airtightly joining. As shown in FIG. 4, a large number (9 in the illustrated example) of electronic component packages 18 undergo sealing processing one by one on the tray 80. Each electronic component package 18 is covered with a cover 16 so as to close the opening of the package body 10 before undergoing the sealing process. The tray 80 is fixed on a work table (not shown), for example. The main body of the galvanometer scanner 30 is also fixedly arranged above the work table. The scanning movement of the YAG pulsed laser beam LA in each electronic component package 18 and the movement of the processing point to another electronic component package 18 are all performed only by the mirror swing movement in the galvanometer scanner 30. The inertia of both scanning mirrors 70X and 70Y is very small, and laser scanning can be performed at almost the same speed as a straight line at an arbitrary curve or bending point.

  5 to 7 show the operation of the electronic component package sealing processing by the electronic component package sealing apparatus of this embodiment. In this embodiment, one electronic component package 18 on the tray 80 oscillates only one pulse of the YAG pulse laser beam LA having an ultra-long pulse from the YAG pulse laser device 20 under the control of the main control unit 24. In addition to being output, the galvanometer scanner 30 scans the YAG pulsed laser light LA so as to go around the peripheral edge of the cover 16 of the electronic component package 18 during the period of one pulse. As shown in FIGS. 5 and 6, the joint portion of the cover 16 and the main body 10 is instantaneously welded by the laser energy near the irradiation position of the YAG pulse laser beam LA, that is, in the vicinity of the beam spot. During one pulse period, the beam spot of the YAG pulsed laser beam LA is constant on the electronic component package 18 (workpiece) at a constant speed without stopping, stopping or interrupting for a moment, and a constant laser output (power density). Therefore, there is no overlap between the beam spots, and the one-stroke seam weld WS is formed over the entire circumference of the cover 16 (FIG. 7).

  As an example, when the size of the cover 16 is 2 mm × 4 mm and the spot diameter or bead width is set to 0.2 mm and the beam scanning speed is set to 100 mm / second, the number of laser shots per package is 1 (piece), The stop processing time is 12 mm / 100 mm / sec = 0.12 sec. The laser output (peak power) is set to, for example, 0.1 to 1.0 kW. In this case, in the YAG pulse laser apparatus 20, the first interval (about approximately 1 pulse period (0.12 seconds)). 0.04 seconds), the first bank 36A lights and drives the excitation light source 42 by power feedback control, and the first bank 36A lights the excitation light source 42 by power feedback control in the middle section (about 0.04 seconds). In the last section (about 0.04 seconds), the third bank 36C drives the excitation light source 42 to turn on by power feedback control.

  Thus, in this embodiment, the seam welding time (sealing time) per package can be shortened to about 1/10 as compared with the conventional laser seam welding method using the overlap method. This can dramatically improve the productivity of the sealing process. In addition, since the laser irradiation time during the sealing process is very short, no heat is generated in the package 18 and the element (crystal piece) 12 is not damaged by the heat.

  The electronic component package 18 in the above embodiment is covered with the cover 16 so that the cover 16 fits into the upper surface opening of the package body 10, and the peripheral end of the cover 16 is laser seam welded to the package body 10 in the form of a butt joint. It was joined with. However, other joint forms are possible. For example, when the cover 16 is placed on the upper surface of the package body 10 so as to be placed one step higher, the peripheral end of the cover 16 is a fillet joint as shown in FIG. In the form, it is joined to the package body 10 by laser seam welding.

  Prior to the sealing process, the process of temporarily fixing the cover 16 to the package body 10 in each electronic component package 18 on the tray 80 can be performed by laser spot welding. The electronic component package sealing apparatus can be used. That is, as shown in FIG. 9 and FIG. 10, a pressing jig rod 82 is applied to each cover 16 from above, and each cover 16 is fixed in a selected position (one or A single pulse laser beam LA ′ from the YAG pulse laser apparatus 20 is condensed and irradiated through a galvanometer scanner 30 to a plurality of locations, and a joint of spot welding WA for temporary fixing can be obtained. The spot welding pulse laser beam LA ′ may be a normal pulse laser beam, and its one pulse period or pulse width may be set to 1 to 10 milliseconds, for example.

  Various other modifications are possible. For example, the cover of the electronic component package may be a disc or a cylinder. Further, the reference value used for the power feedback type waveform control or the peak value of the reference waveform, the up-slope UP and the down-slope DOWN (FIG. 3), etc. can be arbitrarily set. Furthermore, a reference waveform other than the trapezoidal wave can be set. The number of laser power supply circuits 36 (banks) in the YAG pulse laser apparatus is not limited to three, and may be two or less or four or more.

  In the above-described embodiment, the peripheral edge of the cover 16 is irradiated with one pulse of laser light so as to make one round of the peripheral edge of the cover 16 during one pulse period. The part was joined to the package body 10 by seam welding. According to another embodiment of the present invention, as described below, seam welding of a cover corner portion can be performed more satisfactorily in a rectangular electronic component package.

According to the second embodiment, in order to join the square cover 16 to the package body 10 by seam welding in the square electronic component package 18, a total of four pulsed laser beams are used (irradiated). More specifically, from the YAG pulse laser apparatus 20 under the control of the main control unit 24, four pulses pulsed laser beam LA ₁ of, as shown in FIG. _{12, LA 2, LA 3,} LA 4 is desired interval T _a , T _b and T _c are continuously oscillated and output. Then, under the control of the main control unit 24, the first pulse laser beam LA ₁ causes the long side M ₁ of the cover 16 to vertically pass through the one pulse period by the galvanometer scanner 30 as shown in FIG. The second pulse laser beam LA ₂ is irradiated so as to traverse the short side M ₂ of the cover 16 during the one-pulse period, and the third pulse laser beam LA ₃ is covered during the one-pulse period. 16 is irradiated so as to cut the long side M ₃ vertically, and the fourth pulse laser beam LA ₄ is irradiated so as to cut the short side M ₄ of the cover 16 vertically during the one pulse period. Here, four sides M ₁ of the cover 16, M _2, M _3, between the M _4, connection is the start of the short side M ₂ at the end of the long side M _1, long side M ₃ at the end of the short side M ₂ Are connected to each other, and the end of the long side M ₃ is connected to the start of the short side M ₄ (FIGS. 10 and 11).

The moving speeds (scanning speeds) when the respective pulse laser beams LA ₁ , LA ₂ , LA ₃ , LA ₄ cross the sides M ₁ , M ₂ , M ₃ , M ₄ of the cover 16 are set to different values. Although it is possible to set, usually the same speed may be selected. The pulse width of each pulse laser beam LA ₁ , LA ₂ , LA ₃ , LA ₄ is determined according to the dimensions of the four sides M ₁ , M ₂ , M ₃ , M ₄ of the cover 16 and the scanning speed. Also, the laser output waveform, peak value, up slope / down slope, etc. of each pulse laser beam LA ₁ , LA ₂ , LA ₃ , LA ₄ are independent values or the same for each pulse in the power feedback waveform control system. May be set to a value.

Each of the intervals T _a , T _b , and T _c is a period without the pulse laser beam, but the galvanometer scanner 30 continues to operate without stopping during this period. That is, during the intervals T _a , T _b , and T _c , a virtual beam spot without a pulse laser beam (a beam obtained when the pulse laser beam LA is temporarily emitted in the region outside the cover 16). The spot is moved along a predetermined route as indicated by a dotted line in FIG.

In FIG. 11, the galvanometer scanner 30 moves the actual beam spot of the _first pulsed laser beam LA ₁ from the beginning to the end of the long side M ₁ of the case 16, that is, along the straight path S ₂ . From there, the virtual beam spot without the pulsed laser beam is a straight path S ₃ from the end of the long side M ₁ to the first turning point Ja that is _a predetermined distance away from the end of the long side M ₁ , and the first a straight path S ₄ from the turning point J _a from the start point of the short side M ₂ to the second turning point J _b a predetermined distance on the extension of the case 16, from the second turning point J _b The case 16 is sequentially moved along the straight path S ₅ up to the starting point of the short side M ₂ of the case 16.

Next, the actual beam spot of the _second pulse laser beam LA ₂ is moved from the start end to the end of the short side M ₁ of the case 16, that is, along the straight path S ₆ . From there, the virtual beam spot without the pulsed laser beam is a straight path S ₇ to the first turning point Ja that is _a predetermined distance away from the end of the short side M ₂ on the extension of the virtual beam spot. A straight path S ₈ from the turn-back point J _a of the long side M ₃ of the case 16 to a second turn-back point J _b that is a predetermined distance away from the start point of the long side M ₃ of the case 16 and the second turn-back point J _b The case 16 is sequentially moved along the straight path S ₉ up to the starting point of the long side M ₃ of the case 16.

Next, the actual beam spot of the _third pulse laser beam LA ₃ is moved from the start end to the end of the long side M ₃ of the case 16, that is, along the straight path S ₁₀ . From there, the virtual beam spot without the pulsed laser beam is a straight path S ₁₁ from the end of the long side M ₃ to the first turning point Ja that is _a predetermined distance away from the end of the long side M ₃ , and the first path S ₁₁ . A straight path S ₁₂ from the turn-back point J _a of the short side M ₄ of the case 16 to a second turn-back point J _b that is a predetermined distance away from the start point of the short side M ₄ of the case 16, and the second turn-back point J _b The case 16 is sequentially moved along the straight path S ₁₃ up to the start point of the short side M ₄ of the case 16.

Next, the actual beam spot of the fourth pulse laser beam LA ₂ is moved from the start end to the end thereof with respect to the short side M ₄ of the case 16, that is, along the straight path S ₁₄ . From there, the virtual beam spot without pulsed laser light is moved along a straight path S ₁₅ from the end of the short side M _{2 to} the end point END that is a predetermined distance away from the end of the short side M ₂ . Note that just before the _first seam welding is performed on the long side M ₁ of the case 16, the virtual beam spot without the pulse laser beam is moved from the start point START set in the area outside the cover 16 to the long side of the case 16. Move along a straight path S ₁ up to the starting point of M ₁ .

The moving speed of the virtual beam spot in each straight line path S ₁ indicated by the dotted line as described above can be set to a different value. Normally, the moving speed of the virtual beam spot matches the moving speed of the actual beam spot. Good. Note that times t _{1 to} t ₁₅ in each section in FIG. 12 correspond to the movement paths S _{1 to} S ₁₅ of the real beam spot or the virtual beam spot in FIG. 11, respectively.

As an example, when the size of the cover 16 is 2 mm × 4 mm, that is, when M ₂ (S ₆ ), M ₄ (S ₁₄ ) = 2 mm, M ₁ (S ₂ ), M ₃ (S ₁₀ ) = 4 mm, the virtual Each movement path of the beam spot is set to S ₁ , S ₃ , S ₅ , S ₇ , S ₉ , S ₁₁ , S ₁₃ , S ₁₅ = 3 mm, S ₄ , S ₈ , S ₁₂ = 4.2 mm. When the moving speed of the beam spot and the virtual beam spot is set to 410 mm / sec, the number of laser shots per package is 4 (pieces), and the sealing processing time is 48.6 mm ÷ 410 mm / sec≈0.118 sec. .

  Thus, also in the second embodiment, the seam welding time (sealing time) per package can be shortened to 1/10 or less as compared with the laser seam welding method using the conventional overlap method. Of course, since the laser irradiation time for each side of the cover 16 is very short, heat does not flow into the package 18 during the sealing process, and the element (crystal piece) 12 is not damaged by heat.

Moreover, according to this embodiment, as described above, the four pulsed laser beams LA ₁ , LA ₂ , LA ₃ , LA ₄ are aligned in a straight line on the four sides of the rectangular cover 16 with a constant peak power and a constant moving speed. Since each pulse laser beam is irradiated to the start and end of each side at the same peak power and the same moving speed (that is, at the same laser power density) as the intermediate portion, the entire rectangular cover 16 (one round) is irradiated. Seam welding for sealing can be performed more uniformly (in particular, there is no variation between both end portions and intermediate portions of each side).

  Note that the pulse width of each pulsed laser beam LA in this embodiment is a normal pulse of about 10 milliseconds or less. Therefore, the YAG pulse laser device 20 may be composed of a one-bank type laser power supply unit having only one capacitor bank.

1 is a block diagram illustrating an overall configuration of an electronic component package sealing device according to an embodiment of the present invention. It is a block diagram which shows the internal structure of the YAG pulse laser apparatus in the electronic component package sealing apparatus of embodiment. It is a wave form diagram which shows the waveform of each part for showing the effect | action of the power feedback waveform control and bank switching system in the YAG pulse laser apparatus of embodiment. It is a perspective view which shows the structural example of the galvanometer scanner in the electronic component package sealing apparatus of embodiment. It is a perspective view which shows the effect | action in the sealing process in embodiment. It is a partial expansion perspective view which shows the effect | action in the sealing process in embodiment. It is a perspective view which shows the finished state after the sealing process in embodiment. It is a partial expanded side view which shows the example joined to the package main body by the laser seam welding of a fillet joint in embodiment. It is a top view which shows one step of the temporary fix | stop process performed prior to the sealing process of laser seam welding in embodiment. It is an expansion perspective view which shows one step of the said temporary fix | stop process. It is a figure which shows the movement locus | trajectory of the real beam spot and virtual bit spot in another embodiment. It is a wave form diagram which shows the waveform of the pulse laser beam in another embodiment. It is a disassembled perspective view which shows the structure of the electronic component package which can apply this invention. It is a perspective view which shows the sealing process by the conventional laser seam welding. It is a fragmentary perspective view which shows the sealing process by the conventional laser seam welding. It is a wave form diagram which shows the waveform of the pulse laser beam in the conventional laser seam welding for sealing processes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Package main body 12 Crystal piece 14 Electrode 16 Cover 18 Electronic component package 20 YAG pulse laser apparatus 22 Laser optical system 24 Main control part 30 Galvanometer scanner 32 Scanner control part 34 YAG laser oscillator 36A, 36B, 36C Laser power supply circuit 38 Laser output Measurement unit 42 Excitation light source 44 YAG rod (laser medium)
50A, 50B, 50C Capacitor 52A, 52B, 52C Bank Capacitor 54A, 54B, 54C Charging Circuit 56A, 56B, 56C Power Supply Control Unit

Claims (20)

A method of sealing an electronic component package by airtightly bonding a peripheral end portion of a cover placed on a package body having an open top surface,
The pulse laser device oscillates and outputs a single pulse laser beam having a predetermined pulse period, and at the same time controls the galvanometer scanner so that the beam spot of the pulse laser beam moves the peripheral edge of the cover during the pulse period. An electronic component package sealing method in which the peripheral edge portion of the cover is scanned and irradiated so as to make one round, and the peripheral end portion of the cover is joined to the package main body by seam welding over the entire circumference. The electronic component package sealing method according to claim 1, wherein the beam spot of the pulsed laser light makes a round around the peripheral end portion of the cover at a substantially constant speed. 3. The electronic component package sealing method according to claim 1 , wherein the laser output is maintained substantially constant while the beam spot of the pulsed laser light goes around the peripheral end of the cover. 4. A method of sealing an electronic component package by airtightly bonding a peripheral end portion of a rectangular cover placed on a package body having an open top surface,
The pulse laser apparatus oscillates and outputs a first pulse laser beam having a first pulse period and simultaneously controls a galvanometer scanner so that the first pulse laser beam is emitted during the first pulse period. The first pulse laser beam is scanned and applied to the first side of the cover so that a beam spot runs through the first side of the cover, and the peripheral edge of the cover is set to the first side. A first step of joining the package body by seam welding;
The pulse laser device oscillates and outputs a second pulse laser beam having one pulse having a second pulse period, and at the same time controls the galvanometer scanner so that the second pulse laser is emitted during the second pulse period. The second side of the cover is scanned and irradiated with the second pulsed laser light so that a light beam spot cuts the second side of the cover, and the peripheral edge of the cover is moved to the second side. A second step of joining the package body by seam welding at a side;
The pulse laser device oscillates and outputs a third pulse laser beam having one pulse having a third pulse period, and at the same time controls the galvanometer scanner so that the third pulse laser is emitted during the third pulse period. The third pulse laser beam is scanned and applied to the third side of the cover from above so that a light beam spot runs through the third side of the cover, and the peripheral edge of the cover is A third step of seam welding to the package body at a third side;
The pulse laser device oscillates and outputs a single pulse of a fourth pulse laser beam having a fourth pulse period, and at the same time controls the galvanometer scanner so that the fourth pulse laser is emitted during the fourth pulse period. The fourth pulse laser beam is scanned from above the fourth side of the cover so that the beam spot of the light cuts through the fourth side of the cover, and the peripheral edge of the cover is And a fourth step of joining the package main body by seam welding at a fourth side. In the four sides of the cover, the start of the second side is connected to the end of the first side, the start of the third side is connected to the end of the second side, and the end of the third side is connected. the starting end connected to the fourth side, the end of the fourth side leads to the starting end of the first side, the electronic component package sealing method according to claim 4. No pulse laser beam between the first step and the second step, between the second step and the third step, and between the third step and the fourth step. interval are provided, the electronic component package sealing method according to claim 4 or claim 5. During the interval moves the virtual beam spot without pulsed laser light outside the region of the cover by the galvanometer scanner, an electronic component package sealing method according to claim 6. The movement trajectory of the virtual beam spot is
A first straight path from the end of one side of the cover on which seam welding has been performed in the immediately preceding process to a first turning point that is a predetermined distance away from the extension;
A second straight path from the first turn point to a second turn point that is a predetermined distance away from the starting end of one side of the cover to be seam welded in the next step;
The electronic component package sealing method according to claim 7 , further comprising: a third straight path from the second turning point to a start end of one side of the cover where seam welding is to be performed in the next step. Each said pulsed laser beam of the beam spot is traversing the respective sides of the cover at a substantially constant speed, the electronic component package sealing process according to any one of claims 4-8. While the beam spot of each of said pulsed laser beam to traverse the respective sides of the cover to maintain a substantially constant the laser output, the electronic component package sealing process according to any one of claims 4-9. Before performing seam welding processing on the peripheral edge of the cover to the package body, each of the selected one or a plurality of selected peripheral edges of the cover is locally irradiated with a pulse laser beam for temporary fixing. The electronic component package sealing method according to any one of claims 1 to 10 , wherein spot welding is performed. The pulsed laser beam is YAG pulsed laser beam, an electronic component package sealing process according to any one of claims 1 to 11. The peripheral edge of the cover is welded butt joints on the package body, an electronic component package sealing process according to any one of claims 1 to 12. The peripheral edge of the cover is welded meat joint corner in the package body, an electronic component package sealing process according to any one of claims 1 to 12. The package body and the cover is a metal, respectively, electronic component package sealing process according to any one of claims 1-14. An electronic component package sealing device for sealing an electronic component package by airtightly bonding a peripheral end portion of a cover placed on a package body having an open top surface,
A pulse laser oscillating unit that oscillates and outputs a pulsed laser beam having a laser medium and a pumping light source that optically pumps the laser medium, and having a laser output corresponding to the power supplied to the pumping light source;
A scan mirror for reflecting the pulse laser beam from the pulse laser oscillation unit toward a peripheral end portion of the cover on the package body, and the pulse laser beam with respect to the peripheral end portion of the cover; A galvanometer scanner that moves the beam spot along a predetermined path,
A laser output measuring unit for measuring a laser output of the pulse laser beam generated from the pulse laser oscillation unit;
A laser power supply unit that supplies power to the excitation light source of the pulse laser oscillation unit so that a laser output measurement value obtained from the laser output measurement unit matches a desired laser output setting value or waveform;
The pulse laser beam of one pulse generated from the pulse laser oscillation unit is irradiated to the peripheral end portion of the cover, and the beam spot of the pulse laser beam makes one round of the peripheral end portion of the cover during one pulse period. the electronic component package sealing device and a control unit for controlling in cooperation with said galvanometer scanner and the laser power supply unit at the same time. The laser power source is
A capacitor for accumulating electric power supplied to the excitation light source of the pulse laser oscillation unit, a charging circuit for charging the capacitor to a preset charging voltage, and a laser output measurement value from the laser output measurement unit as the laser output setting A laser power supply circuit including a power supply control circuit that performs switching control of the switching element so that a comparison error is zero compared with a value or a waveform is connected in parallel to the laser oscillation unit,
The plurality of laser power supply circuits are sequentially switched at a predetermined timing during one pulse period, and a pulse current having a duration of one pulse period is supplied to the pulse laser oscillation unit .
The electronic component package sealing apparatus according to claim 16. An electronic component package sealing device for sealing an electronic component package by airtightly bonding a peripheral end portion of a rectangular cover placed on a package body having an open top surface,
A pulse laser oscillating unit that oscillates and outputs a pulsed laser beam having a laser medium and a pumping light source that optically pumps the laser medium, and having a laser output corresponding to the power supplied to the pumping light source;
A scan mirror for reflecting the pulse laser beam from the pulse laser oscillation unit toward a peripheral end portion of the cover on the package body, and the pulse laser beam with respect to the peripheral end portion of the cover; A galvanometer scanner that moves the beam spot along a predetermined path,
A laser output measuring unit for measuring a laser output of the pulse laser beam generated from the pulse laser oscillation unit;
A laser power supply unit that supplies power to the excitation light source of the pulse laser oscillation unit so that a laser output measurement value obtained from the laser output measurement unit matches a desired laser output setting value or waveform;
Four pulse laser beams continuously generated from the pulse laser oscillation unit with a desired interval in between are irradiated on the four peripheral edges of the cover, and the beam spot of each pulse laser beam is in the one pulse period. And a control unit that controls the laser power supply unit and the galvanometer scanner in cooperation with each other so as to cut the corresponding sides of the cover vertically. The laser power source is
A capacitor for accumulating electric power to be supplied to an excitation light source of the pulse laser oscillation unit;
A charging circuit for charging the capacitor to a preset charging voltage;
For each pulsed laser beam, a laser power measurement value from the laser power measurement unit is compared with the laser power setting value or waveform, and a power supply control circuit that controls the switching element so as to make a comparison error zero. The electronic component package sealing device according to claim 18 . The laser medium is a YAG rod, the pulsed laser light is a YAG pulse laser beam, an electronic component package sealing apparatus according to any one of claims 16-19.

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