JP2022140181A - Laser soldering apparatus - Google Patents

Abstract

To provide a laser soldering apparatus which can detect the temperature in a portion where the heat resistance is low in the vicinity of a soldering portion and can perform temperature control with the detection temperature as one parameter.SOLUTION: A laser soldering apparatus 1 according to the present invention comprises at least: a laser beam irradiation device 12 which emits a laser beam to a prescribed soldering portion 73; a temperature detection device 20 which detects the temperature of the soldering portion 73; an imaging device 30 which captures an image of the periphery of the soldering portion; a vicinity temperature detection device 21 which detects the temperature of an electronic component 71 in the vicinity of soldering; and a control device which controls the laser beam irradiation device 12 such that the detection temperature detected by the vicinity temperature detection device 21 does not become equal to or greater than the temperature prescribed in the electronic component 71.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laser soldering apparatus that irradiates a laser beam to a soldering location to solder an electronic component to a predetermined location.

Patent Document 1 (Japanese Patent Application Laid-Open No. 2018-176247) aims to perform high-quality soldering by precisely controlling the output of a laser beam so that a soldering point is heated to a target temperature. A laser beam is output along a predetermined control waveform, and when the measured temperature of the soldering point measured by the radiation thermometer does not exceed the predetermined upper limit temperature, the control waveform Disclosed is a laser soldering apparatus that continues control along a control waveform and, when the temperature of the side tip exceeds the upper limit temperature, interrupts control along the control waveform and reduces the output of the laser light.

The laser soldering apparatus disclosed in Patent Document 2 (Japanese Patent Application Laid-Open No. 2019-130584) includes first and second side terminals and first and second pads on both left and right sides of an electronic component on a printed wiring board. Under the control of the control unit, the first and second laser beams, each of which can be independently controlled, are condensed and irradiated onto the solder interposed between the It is.

The soldering system disclosed in Patent Document 3 (Japanese Patent Application Laid-Open No. 2020-25985) generates at least a first beam and a second beam, and directs the first beam to a first element of the soldering area. During a multi-beam scanner soldering process for guiding and guiding said second beam to a second element of said soldering area, at least a first temperature of said first element and a second temperature of said second element. A system comprising a sensor for simultaneously detecting temperature and a controller for adjusting parameters of said first beam and said second beam provided that said first temperature and said second temperature are substantially different. Something is disclosed.

Patent Document 4 (Japanese Patent Application Laid-Open No. 11-347762) discloses a welding head having an optical system for obtaining twin beams obtained by splitting a laser beam into two optical paths for welding to a support of a tubular body. Discloses a seal welding method that moves along the periphery of the end face so as to weld two locations in the thickness direction of the tubular body at the same time.

Patent Document 5 (Japanese Patent No. 2902550) has an optical transmission system that transmits and emits a laser beam, and has a plurality of surfaces that are in contact with each other at edges. A beam splitting section for splitting a laser beam emitted from an optical transmission system at a variable split ratio, and a beam splitting section for splitting a laser beam emitted from the beam splitting section. a collective lens unit that is common to a plurality of laser beams and that collects the plurality of laser beams at different positions; Disclosed is a laser processing machine having a rotary drive mechanism for rotating.

JP 2018-176247 A JP 2019-130584 A JP 2020-25985 A JP-A-11-347762 Japanese Patent No. 2902550

In the past, the temperature of the soldering point was measured in real time using a radiation thermometer, and the output of the laser beam was controlled so that the measured temperature reached the target temperature. In addition, it is difficult to control the output of the laser beam to match the target temperature with high accuracy, and there have been cases where the soldering points are not heated to the proper temperature, resulting in solder defects.

For this reason, for example, in the laser soldering apparatus disclosed in Patent Document 1, a first step of preheating the soldering point and a second step of melting the supplied solder with a laser beam and diffusing it to the soldering point are performed. and a third step of post-heating the solder diffused to the soldering point with a laser beam. Setting a control waveform for controlling output and irradiation time, setting an upper limit temperature higher than a target temperature, and performing soldering along the first, second, and third steps, the laser beam The output and irradiation time are waveform controlled based on the control waveform, and the temperature of the soldering point is measured with a radiation thermometer and compared with the upper limit temperature, and if the measured temperature is lower than the upper limit temperature, the waveform is controlled as it is. When the measured temperature exceeds the upper limit temperature, the waveform control is canceled and the output of the laser light is lowered.

Further, in Patent Document 2, the temperature measurement step receives infrared rays generated respectively from solder near the first and second terminals during irradiation of the first and second laser beams, and photoelectrically converts the infrared rays into the solder. generating first and second measured temperature signals representative of temperature; a laser power control step comparing said first and second measured temperature signals to a reference value; The laser outputs of the two laser beams are independently binary controlled, the laser outputs of the first and second laser beams are increased at a constant rate from the start of laser irradiation, and the first measurement temperature signal is obtained. After reaching a reference value corresponding to the reference temperature, the laser output of the first laser light is controlled so that the laser output value at the time of arrival or its vicinity is maintained, and the second measurement temperature After the signal reaches a reference value corresponding to the reference temperature, the laser output of the second laser light is controlled so that the laser output value at the time of arrival or its vicinity is maintained. .

Further, in US Pat. No. 5,200,000, sensors measure a first temperature of a first element of the soldering area through which the first beam is guided and a temperature of a second element of the soldering area through which the second beam is guided. A second temperature is sensed simultaneously, and the controller adjusts parameters of the first beam and the second beam provided that the first temperature and the second temperature are substantially different. is.

In Patent Document 4, when welding a tubular body to a support, a welding head having an optical system for obtaining twin beams obtained by splitting a laser beam into two optical paths is mounted on the end surface of the tubular body in two directions in the thickness direction of the tubular body. In Patent Document 5, twin beams consisting of a main laser beam and an auxiliary laser beam are emitted, and the roof prism is moved left and right. Thus, the intensities of the main laser beam and the auxiliary laser beam can be adjusted.

As described above, in the prior art, when the temperature of a portion irradiated with a laser beam is detected and the output of the laser beam is controlled according to the detected temperature, the rate of temperature rise differs according to the heat capacity of the soldering portion. , the peripheral edge of the soldering point may become excessively hot. If the soldered portion reaches an abnormally high temperature, there is a risk that circuit board wiring that is connected to the soldered portion will be melted to cause disconnection, or that electronic components will be destroyed due to heat. In addition, nowadays there is a demand for the use of Pb-free solder. The thermal effect on the

Furthermore, in electronic components, especially ICs, there is a possibility that semiconductor chips may be destroyed by thermal shock due to a sudden temperature rise. problems such as a decrease in

In view of the above, the present invention provides a laser soldering apparatus capable of detecting the temperature of a portion having low heat resistance in the vicinity of the soldering portion and performing temperature control using this detected temperature as one parameter. It is in.

The present invention comprises at least a laser beam irradiation device that irradiates a predetermined soldering portion with a laser beam, a temperature detection device that detects the temperature of the soldering portion, and an imaging device that captures an image of the periphery of the soldering portion. In the laser soldering apparatus configured, a proximity temperature detection device for detecting the temperature of the electronic component in the vicinity of the soldering, and a temperature detected by the proximity temperature detection device so as not to exceed a temperature specified for the electronic component and a control device for controlling the laser beam irradiation device.

The laser light irradiation device is composed of a laser generator for generating laser light of a predetermined wavelength and a laser light guide mechanism for guiding the laser light of the predetermined wavelength generated by the laser generator to a soldering position. preferably

Further, the laser light irradiation device includes a laser generator that generates a laser beam of a predetermined wavelength, spectroscopic means that disperses the laser beam of a predetermined wavelength generated by the laser generator, and It is desirable that the laser light guide mechanism irradiate two soldering positions positioned at a predetermined interval with a laser light guide mechanism.

Furthermore, it is desirable that the spectroscopic means disperse the light so that the temperatures of at least two soldering points detected by the temperature detecting means are well balanced. Further, it is preferable that the spectroscopic means is a prism having a ridgeline on the incident side of the laser beam, and the ridgeline is movable to the left and right with respect to the incident side of the laser beam.

It should be noted that the electronic component is an electronic component that is affected by heat due to heat conduction from a soldered portion, such as an IC, a resistor, a capacitor, etc. mounted on a substrate, and more preferably the substrate wiring itself. . In the case of an electronic component that has soldering points at regular intervals on both sides, it is efficient to split the laser beam by a spectroscopic means and solder it all at once. It is necessary to observe the temperature rise of the electronic components so as not to suffer.

In addition, electronic components, especially ICs, may be damaged by thermal shock due to a sudden temperature rise, and in aluminum electrolytic capacitors, etc., the thermal effect will reduce the capacitance and shorten the estimated life. In order to avoid problems such as these, a heat-resistant temperature is set for each electronic component to be soldered, and the output of the laser generator is controlled so that the temperature of the electronic component detected by the temperature detection device does not exceed the heat-resistant temperature. It is something to do.

Further, the control device according to the present invention can control the output of the laser beam based on the temperature of the electronic component, and can also control the output of the laser beam based on the temperature of the soldered portion. desirable. Especially in the case of soldering with twin lasers that split laser light, it is necessary to adjust the intensity of each of the twin lasers, such as when the heat capacity of each soldering point is different. It is possible.

According to the present invention, the temperature of the electronic component that is affected by the heat from the soldered portion is displayed, and the output of the laser generator is controlled based on this temperature. It is possible to prevent breakage of electronic parts.

FIG. 1 is a schematic configuration diagram of a laser soldering apparatus according to Embodiment 1 of the present invention. FIG. 2 is an explanatory diagram showing an imaging area, a laser area, and a sensor area in the vicinity of a soldering location of the laser soldering apparatus according to the first embodiment. FIG. 3 is a schematic configuration diagram of a laser soldering apparatus according to Embodiment 2 of the present invention. FIG. 4(a) is an explanatory diagram showing an imaging area, a laser area, and a sensor area in the vicinity of a soldering position of a laser soldering apparatus according to Example 2, and FIG. 4(b) is a side view thereof. FIG. 5(a) is an explanatory diagram showing the spectrum by the prism when the laser beam on the left side is intensified, and FIG. 5(b) is an explanatory diagram showing the imaging area, the laser area, and the sensor area by the spectrum. . FIG. 6(a) is an explanatory diagram showing the spectrum by the prism when the laser beam on the right side is intensified, and FIG. 6(b) is an explanatory diagram showing the imaging area, the laser area and the sensor area by the spectrum. . FIG. 7 is a schematic configuration diagram of a laser soldering apparatus according to Embodiment 3 of the present invention. FIG. 8 is a flow chart showing an example of control of the laser soldering apparatus of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.

A laser soldering apparatus 1 according to an embodiment of the present invention includes a laser generator 10 that generates a laser beam of a predetermined wavelength, a temperature detector 20 that receives infrared rays to detect the temperature, and a predetermined temperature near the soldering location. , a laser light guide mechanism 40 for guiding a laser beam of a predetermined wavelength generated by the laser generator 10 to a laser area (soldering location) 70, a laser area (solder An image guide mechanism 50 guides an image from an image pickup device 30 to an image pickup device 30, and infrared rays emitted from a desired position (temperature detection area) 76 in the vicinity of the laser area (soldering location) 70 are detected by the temperature detection device. 20 is equipped with an infrared guide mechanism 60.

The laser axis of the laser generator 10 uses a general wavelength band of 800 to 1100 nm, and semiconductor lasers and fiber lasers are typical examples. As for the input method of the laser axis, fiber transmission with good handling is convenient and can be installed in a place away from the light source. Laser light emitted from the fiber is optically converted into parallel light by a collimating lens 11 .

The laser light guide mechanism 40 includes a total reflection mirror 41 arranged at an angle of 45° for total reflection of the laser beam converted into parallel light by the collimating lens 11 in the horizontal direction of 90°, and the total reflection mirror 41 , and a first dichroic filter 42 for reflecting the laser beam totally reflected by the total reflection mirror 41 toward the soldering part, and a condenser lens (collimate lens) 43. Configured.

The photographing device 30 receives and images the visible light band from the laser area (soldering location) 70, and the visible light from the laser area (soldering location) 70 passes through the image guide mechanism 50. is input to the photographing device 30. The image guide mechanism 50 is composed of a condenser lens 43, a second dichroic filter 42, a second dichroic filter 51, a total reflection mirror 52, and a condenser lens 53. Visible light passes through the condenser lens 43 and While being transmitted through the first dichroic filter 42, it is totally reflected in the second dichroic filter 51 arranged at an angle of 45° facing the first dichroic filter 42 in the vertical direction, and further reflected in the second dichroic filter 42 in the horizontal direction. The light is totally reflected by a total reflection mirror 52 arranged at an angle of 45° facing the dichroic filter 51 and is input to the photographing device 30 . 54 is a position adjusting mechanism.

The temperature detection device 20 detects the temperature of the soldering portion 71 of the electronic component 71 , and detects the temperature from the electronic component 71 in the vicinity of the laser area (soldering portion) 70 via the infrared guide mechanism 60 . 2 to 2.5 .mu.m band infrared rays emitted from the electronic parts 71 are detected by the infrared guide mechanism 60. The light passes through the condensing lens 43 , first dichroic filter 42 and second dichroic filter 51 , is condensed by the condensing lens 61 , and reaches the temperature detection device 20 . 62 is a position adjusting device. The first dichroic filter 42 totally reflects only laser light, and the second dichroic filter 51 totally reflects only visible light.

FIG. 2 shows a photographing range 75 photographed by the photographing device 30, a temperature detection area 76 of the temperature detection device 20 focused on the electronic component 71, a soldering portion 73 temporarily joined on the substrate wiring 74, and the electronic component. 7 shows a laser area (soldering location) 70 irradiated with a laser beam for soldering a terminal 72 of 71. FIG.

With the above configuration, the temperature detection area 6 is adjusted to the laser area by adjusting the incident angle to the first dichroic filter 42 by the position adjustment mechanism (tilt mechanism) 62 based on the image photographed by the photographing device 30. The focus can be moved to 70 or a temperature detection area 76 in the vicinity of the laser beam.

The temperature of the electronic component 71 is detected by the temperature detection device 30, and the output of the laser generator 10 is controlled so that the detected temperature does not exceed, for example, the heat resistance temperature of the electronic component 71 or the set temperature. It is possible to prevent problems such as breakage of the electronic component 71 due to soldering heat.

A twin laser soldering apparatus 1A according to Embodiment 2 of the present invention includes, for example, a laser generator 10, a collimator lens 11, a total reflection mirror 41, a first dichroic filter 42 and a condenser lens 43, as shown in FIG. and a laser light guide mechanism 40 having a spectral prism 80, and a laser light irradiation device 12 for irradiating laser light onto two soldering positions positioned at a predetermined interval. The twin-laser soldering apparatus 1A further includes a temperature detection device 20 for detecting the temperature of the soldering location, and an imaging device 30 for capturing an image of the periphery of the soldering location.

Furthermore, the twin laser soldering apparatus 1A of the present invention includes a proximity temperature detection device 21 that detects the temperature of the electronic component 71 near the soldering area, and the temperature detected by the proximity temperature detection device 21 is detected by the electronic component 71. and a control device for controlling the laser light generator 10 so that the temperature does not exceed a prescribed temperature.

Further, the laser beam irradiation device 12 includes a spectral prism 80 as a spectral means for spectrally splitting the laser beam of a predetermined wavelength generated by the laser generator 10 . The spectral prism 80 has a ridgeline 81 for splitting the laser beam on the side facing the laser generator 10, and separates the laser beam output from the laser generator 10 into left and right along the ridgeline 81. It is.

The twin beams split by the spectroscopy prism 80 pass through the laser light guide mechanism 40, for example, as shown in FIGS. and the soldering locations 73a and 73b of the electronic component 71 are irradiated. The laser beams are shown as laser areas 70a and 70b, respectively.

Usually, when the heat capacities of the two soldering points 73a and 73B are the same, the splitting prism 80 is arranged so that the left and right twin beam outputs are uniform. Further, when the heat capacity of the left soldering portion 73a is large, the temperature rise of the soldering portion 73a is slower than that of the right soldering portion 73b. to make the spectral ratio of the laser beam to the left larger than that of the laser beam to the right, as shown in FIG. Since the laser beam at the soldered portion 73a can be strengthened, the left and right soldered states can be made uniform.

6A and 6B show that, contrary to the case shown in FIG. 5, when the heat capacity of the soldering portion 73b on the right side is large, the temperature rise of the soldering portion 73b is greater than that of the soldering portion 73a on the left side. Therefore, by moving the light-splitting prism to the right side and increasing the spectral ratio of the laser beam to the right side as compared to the laser beam to the left side, the laser beam to the left soldering portion 73a is suppressed, and the right side laser beam is suppressed. This indicates that the soldering state on the left and right sides can be made uniform because the laser beam at the soldering point 73b can be strengthened.

A twin-beam soldering apparatus 1B according to a third embodiment of the present invention is arranged on the downstream side of the collimating lens 11 so as to split the laser beam converted into parallel light by the collimating lens 11 in the laser beam irradiation device 12. , and a spectral prism 80'.

In the third embodiment, as in the case of the second embodiment, the same reference numerals are given to the same parts or the parts having the same effects as in the first embodiment, and the description thereof will be omitted. Therefore, the twin-beam soldering apparatus 1B according to the third embodiment also has the same effects as the twin-beam soldering apparatus 1A according to the second embodiment.

The control of the twin-beam soldering apparatuses 1A and 1B according to the second and third embodiments described above is shown, for example, by a flow chart as shown in FIG.

In the control starting from step 100, for example, the temperature Ta of the left soldering point 73a is detected at step 110, the temperature Tb of the right soldering point 73b is detected at step 120, and the electronic component 71 temperature Tc is detected.

In step 140, the temperatures Ta and Tb of the left and right soldering points 73a and 73b are compared. By increasing the spectral ratio of the laser beam, for example, as shown in FIGS. It is intended to balance left and right.

If the temperature Ta is not high in step 140, the process proceeds to step 150 to determine whether the temperature Ta is lower than the temperature Tb. If the temperature Ta is lower than the temperature Tb in step 150, the process proceeds to step 170 to move the spectroscopy prism 80 (80') to the left to increase the spectral ratio of the left laser beam. As shown in 5(a) and 5(b), the laser beam directed to the right soldering portion 73b is reduced and the laser beam directed to the left soldered portion 73a is increased to balance the left and right sides.

When the left and right laser beams are balanced by the above control, the temperature Ta and the temperature Tb are equal in the judgments of steps 140 and 150. It is determined whether the temperature Tc is greater than a predetermined value α. The predetermined value α is desirably set based on the limit temperature, allowable temperature, etc. of the electronic component 71 .

If it is determined in step 180 that the temperature Tc of the electronic component 71 is higher than the predetermined value α, the process proceeds to step 190 to reduce the output of the laser generator 10 to prevent the electronic component 71 from being affected by the temperature. When the temperature Tc of the electronic component 71 is equal to or lower than the predetermined value α, the process proceeds to step 200. When the soldering of the soldering points 73a and 73b of the electronic component 71 is completed, the control is completed in step 200, If soldering has not been completed, the process returns to step 110 to continue temperature control.

As described above, according to the present invention, the temperature of the electronic component 71 is detected in the laser soldering apparatus 1 of the first embodiment and the twin-beam laser soldering apparatuses 1A and 1B of the second and third embodiments, can be adjusted, it is possible to suppress or prevent the thermal influence of the electronic component 71 caused by soldering. As a result, it is possible to prevent the electronic parts, which have been soldered with much effort, from actually becoming defective due to the influence of heat, and to extend the life of the electronic parts.

Reference Signs List 1 laser soldering device 1A, 1B twin laser soldering device 10 laser generator 11 collimator lens 20 temperature detector 21 near temperature detector 30 imaging device 40 laser beam guide mechanism 41 total reflection mirror 42 first dichroic filter 43 condensing light Lens 50 Image guide mechanism 51 Second dichroic filter 52 Total reflection mirror 53 Condenser lens 54 Position adjustment mechanism 60 Infrared guide mechanism 61 Condenser lens 62 Position adjustment mechanism 70, 70a, 70b Laser area 71 Electronic parts 72, 72a , 72b terminals 73, 73a, 73b soldering points 74, 74a, 74b substrate wiring 75 image area 76 temperature detection area 80 spectral prism

Claims (5)

A laser comprising at least a laser beam irradiation device for irradiating a predetermined soldering portion with a laser beam, a temperature detecting device for detecting the temperature of the soldering portion, and a photographing device for capturing an image of the periphery of the soldering portion. In a soldering device,
A vicinity temperature detection device for detecting the temperature of the electronic component in the vicinity of the soldering; A laser soldering apparatus comprising: a controller for controlling the laser soldering apparatus; The laser beam irradiation device is composed of a laser generator that generates a laser beam of a predetermined wavelength and a laser beam guide mechanism that guides the laser beam of the predetermined wavelength generated by the laser generator to a soldering position. 2. The laser soldering device according to claim 1, characterized by: The laser beam irradiation device includes a laser generator that generates a laser beam of a predetermined wavelength, spectroscopic means that disperses the laser beam of a predetermined wavelength generated by the laser generator, and laser beams that are separated by the spectroscopic means. 2. The laser soldering apparatus according to claim 1, further comprising a laser light guide mechanism for irradiating two soldering positions positioned at a predetermined interval. 4. The laser soldering apparatus according to claim 3, wherein said spectroscopic means disperses light so that the temperatures of at least two soldering points detected by said temperature detecting means are well balanced. 5. The laser soldering apparatus according to claim 4, wherein said spectroscopic means is a prism having a ridgeline on the laser beam incidence side, and said ridgeline is movable left and right with respect to said laser beam incidence side. .

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