Semiconductor laser cleaning device and semiconductor laser cleaning method

Abstract

A holder (4) holds the semiconductor laser (1). A first nozzle (5) and a second nozzle (6) simultaneously blow airflows (8) containing dry ice particles (7) from different directions onto the same region of the end face (2). A housing (10) houses the holder (4), the first nozzle (5), and the second nozzle (6). Exhaust units (11, 12) exhaust the foreign matter (3) removed from the end face (2) from the housing (10).

Description

[Technical field]

[0001] The present disclosure relates to a semiconductor laser cleaning apparatus and a semiconductor laser cleaning method. [Background technology]

[0002] When a semiconductor wafer on which multiple semiconductor lasers are formed is divided into bars, foreign matter such as wafer scraps adhere to the end faces of the semiconductor lasers. Such foreign matter cannot be removed by cleaning with liquids such as water due to the influence of electrical attraction. For this reason, dry ice cleaning is used, in which an airflow containing dry ice particles is blown onto the end faces (see, for example, Patent Document 1). Since the sublimation energy generated when the dry ice particles evaporate is applied to the foreign matter, the foreign matter is more easily removed than by simply blowing an airflow. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2021 / 100626 Summary of the Invention [Problem to be solved by the invention]

[0004] However, conventional dry ice cleaning, in which an airflow containing dry ice particles is blown from one direction, sometimes fails to adequately remove foreign matter from the chip end surface.

[0005] The present disclosure has been made to solve the above-mentioned problems, and its object is to provide a semiconductor laser cleaning apparatus and a semiconductor laser cleaning method that can improve the cleaning power of dry ice cleaning. [Means for solving the problem]

[0006] A semiconductor laser cleaning device according to the present disclosure includes a holder for holding a semiconductor laser having an end face, a first nozzle and a second nozzle for simultaneously blowing airflows containing dry ice particles onto the same region of the end face from different directions, a housing for accommodating the holder, the first nozzle, and the second nozzle, and an exhaust unit for exhausting foreign matter removed from the end face from the housing. The first nozzle blows the airflow from a direction that is equal to or greater than 0 degrees and smaller than 90 degrees with respect to the end face, and the second nozzle blows the airflow from a direction perpendicular to the end face. It is characterized by: Effect of the Invention

[0007] In this disclosure, airflows containing dry ice particles are blown simultaneously from two different directions onto the same area of ​​the facet of the semiconductor laser, which allows the sublimation energy generated when the dry ice particles collide and vaporize to be applied to the foreign matter from two different directions simultaneously, improving the cleaning power of dry ice cleaning. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a semiconductor laser cleaning apparatus according to a first embodiment. [Diagram 2] 2 is a flowchart of a semiconductor laser cleaning method according to the first embodiment. [Diagram 3] FIG. 1 is a diagram for explaining two-flow dry ice cleaning. [Figure 4] FIG. 4 is a diagram showing a modified example of the semiconductor laser cleaning apparatus according to the first embodiment. [Diagram 5] FIG. 11 is a perspective view showing a part of a semiconductor laser cleaning apparatus according to a second embodiment. [Figure 6] FIG. 11 is a diagram showing a semiconductor laser cleaning apparatus according to a third embodiment. [Figure 7] FIG. 11 is a diagram showing a semiconductor laser cleaning apparatus according to a fourth embodiment. [Figure 8] 13 is a flowchart of a semiconductor laser cleaning method according to the fourth embodiment. [Figure 9] FIG. 13 is a diagram showing a semiconductor laser cleaning apparatus according to a fifth embodiment. [Figure 10]13 is a flowchart of a semiconductor laser cleaning method according to the fifth embodiment. [Figure 11] FIG. 13 is a diagram showing a semiconductor laser cleaning apparatus according to a sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A semiconductor laser cleaning apparatus and a semiconductor laser cleaning method according to an embodiment will be described with reference to the drawings. The same or corresponding components are designated by the same reference numerals, and repeated description may be omitted.

[0010] Embodiment 1 FIG. 1 is a diagram showing a semiconductor laser cleaning apparatus according to a first embodiment. The semiconductor laser 1 to be cleaned is a semiconductor wafer cleaved into bars. The semiconductor laser 1 has an end face 2 which is a cleaved surface. The end face 2 is an emission end face from which laser light is emitted or a rear end face on the opposite side. A foreign object 3 is attached to the end face 2. The foreign object 3 is wafer scraps or the like generated when the semiconductor wafer is cleaved, and is made of a semiconductor material.

[0011] A holder 4 holds the semiconductor laser 1. Liquid carbon dioxide is supplied into a first nozzle 5 and a second nozzle 6, and is transformed into dry ice particles 7. The first nozzle 5 and the second nozzle 6 simultaneously blow airflows 8 containing the dry ice particles 7 onto the same region of the end face 2 from different directions. This removes the foreign matter 3 from the end face 2.

[0012] Specifically, the first nozzle 5 blows the airflow 8 obliquely or parallel to the end face 2. That is, the first nozzle 5 blows the airflow 8 from a direction greater than or equal to 0 degrees and less than 90 degrees to the end face 2. The second nozzle 6 blows the airflow 8 from a direction perpendicular to the end face 2.

[0013] The housing 10 houses the holder 4, the first nozzle 5, and the second nozzle 6. An exhaust unit 11 is provided on the side of the housing 10, and an exhaust unit 12 is provided on the bottom surface of the housing 10. The exhaust units 11 and 12 exhaust the foreign matter 3 removed from the end face 2 from the housing 10 together with the air inside the housing 10. This allows the foreign matter 3 to be removed from the housing 10 so that it does not reattach to the semiconductor laser 1.

[0014] When dry ice cleaning is performed, the foreign matter 3 may become electrically charged. The charged foreign matter 3 is likely to reattach to the semiconductor laser 1 due to electrostatic force. Therefore, an ionizer 13 and an electrostatically charged sheet 14 are provided inside the housing 10. The ionizer 13 releases ions into the air inside the housing 10 to remove the charge from the foreign matter 3. The electrostatically charged sheet 14 is positively or negatively charged, and removes the charge from the foreign matter 3 that comes into contact with the electrostatically charged sheet 14. The foreign matter 3 from which the charge has been removed is discharged from the exhaust sections 11 and 12 without reattaching to the semiconductor laser 1.

[0015] Next, a semiconductor laser cleaning method using the semiconductor laser cleaning device according to the present embodiment will be described. FIG. 2 is a flow chart of the semiconductor laser cleaning method according to the first embodiment. First, ions are generated by the ionizer 13 (step S1). Two-flow dry ice cleaning is performed by simultaneously blowing airflow 8 containing dry ice particles 7 from two different directions onto the same region of the end face 2 of the semiconductor laser 1 using the first nozzle 5 and the second nozzle 6 (step S2). After performing cleaning for a predetermined time, the blowing of the airflow 8 is stopped (step S3). Finally, the ionizer 13 is stopped (step S4). In the two-flow dry ice cleaning, it is preferable that the difference in air volume between the first nozzle 5 and the second nozzle 6 is zero, and the timing of the start and end of blowing of the first nozzle 5 and the second nozzle 6 is the same.

[0016] FIG. 3 is a diagram for explaining two-flow dry ice cleaning. Airflow 8 containing dry ice particles 7 is blown simultaneously from two different directions onto the same area of ​​the end face 2 of the semiconductor laser 1. The size of the dry ice particles 7 is about 10 μm. The dry ice particles 7 collide with the foreign matter 3, vaporize, and expand by about 750 times. The sublimation energy at this time is applied to the foreign matter 3 from two different directions simultaneously. This improves the cleaning power of dry ice cleaning compared to the case where the airflow 8 containing the dry ice particles 7 is blown from one direction. As a result, it is possible to reduce appearance defects due to foreign matter adhesion during visual inspection of the end face 2 of the semiconductor laser 1. In addition, since the dry ice particles 7 have low hardness, they do not damage the end face 2 of the semiconductor laser 1.

[0017] Furthermore, the kinetic energy of the dry ice particles 7 when they collide with the foreign object 3 is proportional to the mass and the square of the velocity of the dry ice particles 7. However, if the collision angle deviates from 90 degrees, part of the kinetic energy slides sideways along the end surface 2. Therefore, since the angle at which the kinetic energy of the collision is maximized is vertical, it is preferable for the second nozzle 6 to blow the airflow 8 perpendicularly to the end surface 2.

[0018] 4 is a diagram showing a modification of the semiconductor laser cleaning apparatus according to the first embodiment. A first nozzle 5 and a second nozzle 6 simultaneously blow airflows 8 containing dry ice particles 7 onto the same region of the end face 2 from oblique directions on the left and right, respectively. In this case as well, sublimation energy is simultaneously applied to the foreign matter 3 from two different directions, thereby improving the cleaning power of dry ice cleaning.

[0019] Embodiment 2 5 is a perspective view showing a part of a semiconductor laser cleaning apparatus according to the second embodiment. The holder 4 holds a plurality of semiconductor lasers 1 in a stack with their end faces 2 facing the same direction. Two nozzle pairs including a first nozzle 5 and a second nozzle 6 are provided. One of the two nozzle pairs blows an airflow onto one end face of the plurality of semiconductor lasers 1. The other of the two nozzle pairs blows an airflow onto the other end face of the plurality of semiconductor lasers 1.

[0020] The width of the area onto which the airflow is blown is several tens of microns, which is the width of one bar of the semiconductor laser 1. Therefore, when cleaning multiple bars of the semiconductor laser 1 attached to the holder 4 using only one nozzle pair, it is necessary to move the nozzle pair by the number of bars. In contrast, since there are two nozzle pairs in this embodiment, two of the multiple bars of the semiconductor laser 1 held by the holder 4 can be cleaned simultaneously. As a result, the processing capacity of the semiconductor laser cleaning device can be improved. The other configurations and effects are the same as those of the first embodiment.

[0021] Third embodiment FIG. 6 is a diagram showing a semiconductor laser cleaning apparatus according to a third embodiment. A plurality of sets each including a holder 4, a first nozzle 5, and a second nozzle 6 are provided in one housing 10. This allows the semiconductor lasers 1 held by the plurality of holders 4 to be cleaned simultaneously. As a result, the processing capacity of the semiconductor laser cleaning apparatus can be improved. The other configurations and effects are the same as those of the first embodiment. Note that each set may be provided with two nozzle pairs as in the second embodiment.

[0022] Fourth embodiment FIG. 7 is a diagram showing a semiconductor laser cleaning device according to a fourth embodiment. In this embodiment, a laser irradiator 15 locally irradiates the end face 2 with high-energy laser light to heat it. A nozzle 16 sprays an airflow 8 containing dry ice particles 7 onto the heated portion of the end face 2 irradiated with the laser light. The laser irradiator 15 is, for example, a deep ultraviolet laser (wavelength 355 nm), and the irradiation time is optional. The size of the heated portion of the end face 2 is, for example, several tens of microns in diameter. The other configurations are the same as those of the first embodiment.

[0023] 8 is a flow chart of a semiconductor laser cleaning method according to the fourth embodiment. First, ions are generated by the ionizer 13 (step S11). Next, the laser irradiator 15 irradiates the end face 2 with laser light to heat it (step S12). The nozzle 16 blows an airflow 8 containing dry ice particles 7 onto the heated portion of the end face 2 irradiated with the laser light (step S13). After cleaning is performed for a predetermined time, the blowing of the airflow 8 and the irradiation of the laser light are stopped (step S14). Finally, the ionizer 13 is stopped (step S15).

[0024] As described above, in this embodiment, airflow 8 containing dry ice particles 7 is blown onto the heated portion of end face 2 irradiated with laser light. This increases the temperature difference ΔT between the dry ice particles 7 and end face 2, and therefore increases the sublimation energy of the dry ice particles 7. This improves the cleaning power of dry ice cleaning. Furthermore, while heating the entire chip to a high temperature affects device characteristics, the effect on device characteristics can be reduced by locally heating end face 2 with laser light.

[0025] Furthermore, if the laser light is ultraviolet light, it is difficult for the laser light to penetrate into the device, so that only the foreign matter 3 and the surface layer of the end face 2 can be heated. Therefore, the effect of removing foreign matter from the end face 2 can be improved without affecting the device characteristics. The irradiation of the laser light in this embodiment may be combined with the two-flow dry ice cleaning in embodiments 1-3.

[0026] Fifth embodiment 9 is a diagram showing a semiconductor laser cleaning apparatus according to a fifth embodiment. In this embodiment, a vibrator 17 ultrasonically vibrates a nozzle 16. For example, the vibrator 17 irradiates the nozzle 16 with parallel energy beams having different frequencies. This phase interference causes interference fringes on the surface of the nozzle 16, and the nozzle 16 is ultrasonically vibrated in response to the mechanical strain caused by this. The frequency of the ultrasonic vibration is 20 kHz or higher. The other configurations are the same as those of the first embodiment.

[0027] 10 is a flow chart of a semiconductor laser cleaning method according to the fifth embodiment. First, ions are generated by the ionizer 13 (step S21). Next, the vibrator 17 ultrasonically vibrates the nozzle 16 (step S22). The airflow 8 containing the dry ice particles 7 is blown from the ultrasonically vibrated nozzle 16 to the end face 2 (step S23). After cleaning is performed for a predetermined time, the vibration of the nozzle 16 and the blowing of the airflow 8 are stopped (step S24). Finally, the ionizer 13 is stopped (step S25).

[0028] As described above, in this embodiment, the nozzle 16 is ultrasonically vibrated. This causes the airflow 8 ejected from the nozzle 16 to vibrate. The vibration effect of the dry ice particles 7 vibrating together with the airflow 8 can improve the cleaning power of dry ice cleaning.

[0029] Moreover, the higher the vibration frequency, the shorter the wavelength becomes, making it more difficult for the vibration to propagate inside the object. In particular, if the vibration frequency is 1 MHz or more, the vibration is less likely to propagate inside the device, so that only the foreign matter 3 and the surface layer of the end face 2 can be vibrated. Therefore, it is preferable that the vibrator 17 vibrates the nozzle 16 at a frequency of 1 MHz or more. This makes it possible to enhance the effect of removing foreign matter from the end face 2 without affecting the device characteristics. Note that this embodiment may be combined with the laser light irradiation of embodiment 4 or the two-flow dry ice cleaning of embodiments 1-3.

[0030] Sixth embodiment 11 is a diagram showing a semiconductor laser cleaning apparatus according to a sixth embodiment. In this embodiment, a vibrator 17 ultrasonically vibrates the holder 4. The frequency of the ultrasonic vibration is 20 kHz or more. The other configurations are the same as those of the first embodiment. By ultrasonically vibrating the holder 4, the semiconductor laser 1 held by the holder 4 is also ultrasonically vibrated. The cleaning power of the dry ice cleaning can be improved by the collision of dry ice particles 7 with the end face 2 of the ultrasonically vibrated semiconductor laser 1.

[0031] In addition, since there is a risk that the semiconductor laser 1 held by the holder 4 may break apart if the holder 4 is vibrated, it is preferable to ultrasonically vibrate the nozzle 16 as in embodiment 5. In addition, this embodiment may be combined with the laser light irradiation of embodiment 4 or the two-flow dry ice cleaning of embodiments 1-3. [Explanation of symbols]

[0032] REFERENCE SIGNS LIST 1 Semiconductor laser, 2 End face, 4 Holder, 5 First nozzle, 6 Second nozzle, 7 Dry ice particles, 8 Air flow, 10 Housing, 11 Exhaust section, 13 Ionizer, 14 Electrostatic sheet, 15 Laser irradiator, 16 Nozzle, 17 Vibrator

Claims

1. A holder for holding a semiconductor laser having an end face, A first nozzle and a second nozzle that simultaneously blow airflow containing dry ice particles onto the same area of ​​the end face from different directions, The holder, the housing that houses the first nozzle and the second nozzle, The housing is equipped with an exhaust section for exhausting foreign matter removed from the end face, The first nozzle blows the airflow from a direction of 0 degrees or more and less than 90 degrees relative to the end face. The semiconductor laser cleaning apparatus is characterized in that the second nozzle blows the airflow from a direction perpendicular to the end face.

2. The holder holds a plurality of the semiconductor lasers, Two nozzle pairs are provided, each including the first nozzle and the second nozzle. One of the two nozzle pairs blows the airflow onto one of the end faces of the plurality of semiconductor lasers. The semiconductor laser cleaning apparatus according to claim 1, characterized in that the other of the two nozzle pairs blows the airflow onto one of the other end faces of the plurality of semiconductor lasers.

3. The semiconductor laser cleaning apparatus according to claim 1 or 2, characterized in that a plurality of sets including the holder, the first nozzle and the second nozzle are provided inside one housing.

4. A holder for holding a semiconductor laser having an end face, A nozzle that blows an airflow containing dry ice particles onto the end face, A vibrator that vibrates the nozzle or the holder ultrasonically, A housing that houses the holder and the nozzle, A semiconductor laser cleaning apparatus, characterized by comprising an exhaust unit for exhausting foreign matter removed from the end face from the housing.

5. The semiconductor laser cleaning apparatus according to claim 4, characterized in that the vibrator vibrates the nozzle at a frequency of 1 MHz or higher.

6. The semiconductor laser cleaning apparatus according to any one of claims 1, 2, 4, or 5, further comprising an ionizer that releases ions into the interior of the housing to remove the charge of the foreign matter.

7. The semiconductor laser cleaning apparatus according to any one of claims 1, 2, 4, or 5, further comprising a chargeable sheet provided inside the housing to remove the charge of the foreign matter.

8. A step of holding a semiconductor laser having an end face with a holder, The process includes the step of simultaneously blowing airflow containing dry ice particles onto the same area of ​​the end face from two different directions, One of the two aforementioned directions is a direction that is 0 degrees or more and less than 90 degrees with respect to the end face. A semiconductor laser cleaning method characterized in that the other of the two aforementioned directions is perpendicular to the end face.

9. A step of holding a semiconductor laser having an end face with a holder, The process includes the step of blowing an airflow containing dry ice particles from a nozzle onto the end face, A semiconductor laser cleaning method characterized by ultrasonically vibrating the nozzle or the holder.

10. The semiconductor laser cleaning method according to claim 9, characterized in that the nozzle is vibrated at a frequency of 1 MHz or higher.

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