Method For Monitoring A Laser Soldering Process, And Laser Soldering System Using A Spectroscope Device

Abstract

A laser soldering system and a method for monitoring a laser soldering process by means of a monitoring device of the laser soldering system, wherein a solder ball is dispensed onto a solderable surface of a substrate by means of a solder ball feeding device of the laser soldering system, wherein the solder ball is at least partially melted by means of a laser device of the laser soldering system, wherein, during the laser soldering process, a light signal is formed which is detected by means of an optical detection unit of the monitoring device, wherein the light signal is dispersed into a spectrum of the light signal by means of a spectroscope device of the monitoring device, wherein the spectrum is analyzed by means of a processing device of the monitoring device, and it is identified on the basis of a composition of the spectrum whether or not a burning of the substrate has occurred during the laser soldering process.

Claims

1. A method for monitoring a laser soldering process by means of a monitoring device of a laser soldering system, wherein a solder ball is dispensed onto a solderable surface of a substrate by means of a solder ball feeding device of the laser soldering system, wherein the solder ball is at least partially melted by means of a laser device of the laser soldering system, wherein, during the laser soldering process, a light signal is formed which is detected by means of an optical detection unit of the monitoring device, wherein the light signal is dispersed into a spectrum of the light signal by means of a spectroscope device of the monitoring device, wherein the spectrum is analyzed by means of a processing device of the monitoring device, and it is identified on the basis of a composition of the spectrum whether or not a burning of the substrate has occurred during the laser soldering process.

2. The method according to claim 1, wherein the spectrum comprises at least one substrate-independent normal portion and, in the case of a burning of the substrate occurring during the laser soldering process, furthermore comprises a substrate-dependent burning portion, wherein a differentiation is made between the substrate-independent normal portion and the substrate-dependent burning portion by means of the processing device.

3. The method according to claim 2, wherein it is identified by means of the processing device on the basis of a presence of the substrate-dependent burning portion in the spectrum whether or not a burning of the substrate has occurred during the laser soldering process.

4. The method according to claim 2, wherein on the basis of a composition of the substrate-dependent burning portion, a material or a material composition of the substrate is determined by means of the processing device.

5. The method according to claim 4, wherein the determination is carried out by means of a comparison of characteristic parameters of the substrate-dependent burning portion with characteristic parameters which are stored in a database of the processing device and which spectroscopically describe a plurality of different materials or material compositions of substrates.

6. The method according to claim 1, wherein it is output by means of the processing device whether or not a burning of the substrate has occurred during the laser soldering process.

7. The method according to claim 1, wherein an operation of the laser soldering system is stopped in the case of a burning of the substrate occurring during the laser soldering process.

8. The method according to claim 1, wherein the light signal is formed due to the melting of the solder ball and, in the case of a burning occurring during the laser soldering process, additionally due to the burning.

9. A laser soldering system, comprising a solder ball feeding device for dispensing a solder ball onto a solderable surface of a substrate and a laser device for at least partially melting the solder ball, wherein the laser soldering system comprises a monitoring device for monitoring a laser soldering process, wherein the monitoring device has an optical detection unit for detecting a light signal which is formed during the laser soldering process and a spectroscope device for dispersing the light signal into a spectrum of the light signal, wherein the monitoring device has a processing device by means of which the spectrum is capable of being analyzed, and it is possible to identify on the basis of a composition of the spectrum whether or not a burning of the substrate has occurred during the laser soldering process.

10. The laser soldering system according to claim 9, wherein the optical detection unit comprises at least one convergent lens.

11. The laser soldering system according to claim 9, wherein the laser soldering system comprises a glass fiber assembly by means of which the light signal is transmittable from the optical detection unit to the spectroscope device.

12. The laser soldering system according to claim 9, wherein the processing device comprises a database in which a plurality of characteristic parameters which spectroscopically describe different materials or material compositions of substrates is capable of being stored.

Description

[0028] Below, preferred embodiments of the disclosure are explained in more detail with reference to the accompanying drawings.

[0029] In the figures:

[0030] FIG. 1 shows a schematic illustration of a laser soldering system;

[0031] FIG. 2 shows a diagrammatic illustration of a spectrum for two different laser soldering processes.

[0032] FIG. 1 shows a schematic illustration of a soldering system 10 which comprises a solder ball feeding device 11 for dispensing a solder ball 21 onto a solderable surface 20 of a substrate 19 and a laser device (not shown in the case at hand) for at least partially melting the solder ball 21. In this case, a laser beam 12 can be formed by means of the laser device, said laser beam, on the one hand, causing the partial melting of the solder ball 21 by impacting on the solder ball 21 and, on the other hand, as shown in FIG. 1, also causing a burning 22 of the substrate 19 by directly impinging on the substrate 19. Due to the melting of the solder ball 21 and due to the burning 22 a light signal 23 is formed.

[0033] Furthermore, the laser soldering system 10 comprises a monitoring device 13 having an optical detection unit 14 for detecting the light signal 23. Furthermore, the optical detection unit 14 comprises a convergent lens 17. The light signal 23 is then transmitted from the optical detection unit 14 to a spectroscope device 15 of the monitoring device 13 via a glass fiber assembly 18 of the laser soldering system 10, the light signal 23 being dispersed into a spectrum of the light signal 23 (not shown in the case at hand) by means of said spectroscope device 15. Moreover, the monitoring device 13 has a processing device 16 by means of which the spectrum can be analyzed, and it is possible to identify on the basis of a composition of the spectrum whether or not a burning 22 of the substrate 19 has occurred during the laser soldering process. An operation of the laser soldering system 10 is stopped in the case of a burning 22 of the substrate 19 occurring during the laser soldering process, in particular in order to prevent further burning 22.

[0034] FIG. 2 shows a spectrum 24 and a spectrum 25 for two different laser soldering processes. In this case, a wavelength in nanometers is illustrated on the axis of abscissas 26 and an intensity in any unit is illustrated on the axis of ordinates 27. The spectrum 24 and 25 comprises a substrate-independent normal portion 28 and 29, respectively, wherein the normal portion 28 essentially coincides with the normal portion 29. Furthermore, the spectrum 24 and 25 comprises a substrate-dependent burning portion 30 and 31, respectively. In the case at hand, it is in particular visible that intensity peaks 32 of the burning portion 30, in particular with respect to a position relative to the axis of abscissas 26, are clearly different from intensity peaks 33 of the burning portion 31. Thus, the burning portions 30 and 31 and the spectrums 24 and 25 come from different substrate types and/or substrates having different materials or material compositions. The position and the height of the intensity peaks 32 and 33 represent a kind of spectral fingerprint on the basis of which a material or a material composition of a substrate can be determined.