JP4186581B2 - Manufacturing method of semiconductor laser device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a semiconductor laser device in which a semiconductor laser device is divided by cleavage from a semiconductor wafer.
[0002]
[Prior art]
In the conventional method of dividing a chip from a semiconductor wafer, a scratch is formed on the edge of the upper surface of the wafer along the cleaved surface of the crystal with a diamond scribing device, and then the lower surface of the wafer is attached to a holding tape and the upper surface of the wafer is removed. In this method, the wafer is pressed against an elastic support tape, and then the edge of the wafer corresponding to the scratch on the wafer is struck by a cutter blade, and the wafer is cleaved from the scratch (see, for example, Patent Document 1).
[0003]
[Patent Document 1]
JP-A-7-201783 (first page, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, the conventional compound semiconductor dividing method has a problem that the cleavage line is bent, the chip is broken, and the yield is lowered.
[0005]
The present invention has been made to solve such a problem, and an object of the present invention is to obtain a method of manufacturing a semiconductor laser device in which the cleavage of the cleavage line is prevented and the yield is improved.
[0006]
Method of manufacturing a semi-conductor laser element engaging Ru in the present invention, a semiconductor layer laminated on the semiconductor wafer, an electrode layer provided via an insulating film on the semiconductor layer, and cleavage in the crystal direction of the semiconductor wafer, a plurality of In the method of manufacturing a semiconductor laser device divided into semiconductor laser devices, an insulating film is provided on the semiconductor layer of the semiconductor laser device in the cleavage region in the cleavage for forming the light emitting surface of the semiconductor laser device, and the cleavage region is insulated. film, provided with a thinner region thickness of the insulating film other than the region forming the above insulating film is provided with the electrode layer on the insulating film of the semiconductor layer of the semiconductor laser device of the cleavage region, the semiconductor after scribe line on the edge of the wafer by stressing to the scribe line by cleavage of the above semiconductor wafer, electrode through the insulating film to the light-emitting surface end And the semiconductor layer is a method of dividing the semiconductor laser device extends.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
FIG. 1 is a flowchart showing a method of manufacturing a semiconductor laser device according to a first embodiment of the present invention in the order of steps. In particular, this is a method applied when manufacturing a semiconductor laser device that is bonded by wire bonding during mounting. FIG. 2 is a plan view schematically showing the semiconductor wafer in which the insulating film is etched in the step of removing at least a part of the insulating film in FIG.
That is, the present invention reduces the resistance to the progress of cleavage by providing a region in the insulating film in the region of the semiconductor wafer that becomes the cleavage portion that is thinner than the insulating film other than the above region. However, in the present embodiment, a method of obtaining the thin insulating film region by removing at least part of the insulating film to be the cleavage region of the insulating film uniformly formed on the entire surface of the semiconductor wafer. Will be described.
[0008]
That is, for example, an n-type layer, an active layer, and a p-type layer are successively grown on a GaAs wafer having a thickness of 600 μm and a size of φ3 inches to stack a semiconductor layer.
An insulating film 3 is provided on the semiconductor layer, and then at least a part of the insulating film is removed by dry etching or wet etching (step (d) in FIG. 1). In consideration of the direction, masking with a resist film by photolithography technique, cleaving the GaAs wafer and dividing it into semiconductor laser elements 2 (step (h) in FIG. 1) is performed on the region to be a cleavage portion. Then, the insulating film removal processing region 1 shown in FIG. 2 is formed.
As the type of the insulating film 3, since SiO ₂ or SiON has a problem in terms of moisture resistance, it is preferable to form a film having a good uniformity and a dense film quality such as SiN with a thermal CVD apparatus.
As a method for removing SiN, there are dry etching using SF ₆ or wet etching using BHF.
Next, a metal is vapor-deposited on the insulating film 3, further gold-plated to provide an electrode layer, polished to a thickness of 100 μm with a polishing machine to form an electrode on the back surface, and then the semiconductor wafer is crystallized with GaAs. Cleaving in the direction and dividing into a plurality of semiconductor laser elements 2.
[0009]
Hereinafter, the cleavage process will be specifically described.
Prepare a disco ring with an adhesive sheet in advance, and fix the surface of the semiconductor wafer opposite to the surface on which the semiconductor layer is crystal-grown to the adhesive surface, and set it on the suction table of a scriber device equipped with a diamond cutter. To do.
Next, with respect to the two rows of patterned semiconductor laser elements , the rotational deviation is corrected so that the moving direction of the diamond cutter is parallel, and the entire length of the wafer extends in the GaAs crystal direction so as to be about 20 mm square. A scribe line is placed in the insulating film removal processing region 1.
After inserting the scribe line, remove it from the table, attach a protective sheet to the surface where the scribe line is inserted, fully support one side of the scribe line, fold it to apply force from the scribe line side, and cleave it. .
By this operation, the wafer is divided into about 20 mm square semiconductor wafers shown in FIG.
[0010]
FIG. 3 shows the semiconductor wafer divided into about 20 mm square as described above, which is related to the method of manufacturing the semiconductor laser device of the present embodiment, to the semiconductor laser device 2 by the primary cleavage line 5 and the secondary cleavage line 51. It is a top view of the semiconductor wafer which shows typically a cleaved state in the process of dividing .
[0011]
In other words, each of the wafers divided into about 20 mm square is pasted on the adhesive sheet, and at the edge of the semiconductor wafer, a scribe line of 0.5 mm to 1 mm is put at the center position of the insulating film removal processing region 1 between the semiconductor laser elements , A primary cleavage line 5 is formed toward the wafer edge direction. Similarly, a secondary cleavage line 51 is formed.
Next, a protective sheet is affixed to the surface on which the scribe line is inserted, and stress is concentrated on the scribe line by applying a force from the opposite surface of the scribe line by three-point bending or the like, thereby promoting cleavage.
In this embodiment, since a part of the SiN film of the insulating film 3 having a dense film quality is removed in particular, the resistance to the progress of cleavage is reduced and the cleavage of cleavage can be suppressed. .
As a result, the effect of improving the cleave amount with respect to the wafer length of 20 mm from ± 20 μm when the insulating film was not removed to ± 3 μm was obtained.
As described above, the semiconductor laser element 2 shown as a region sandwiched between the primary cleavage line 5 and the secondary cleavage line 51 in the figure is manufactured. In the manufacturing process of the semiconductor laser element of the present embodiment, It was possible to prevent the cleavage line from being bent and the semiconductor laser element from being damaged, and the yield was improved.
[0012]
In the case of a semiconductor laser element, as shown in the drawing, it is necessary to leave a part of the insulating layer under the electrode layer 12 without removing it. This is because the primary cleavage surface 5 is a surface from which the laser beam is emitted, and thus the electrode 12 on the light emission surface needs to be insulated from the semiconductor layer.
Furthermore, since the surface from which the laser emits light needs to be a mirror surface, by making a region 1 that has been thinned by removing a part of the insulating film as described above, not only can cleavage be prevented, When viewed microscopically, it is possible to prevent the cleavage surface from being displaced, and to prevent a step (streaks) from being generated on the cleavage surface.
In the present embodiment, no insulation removal treatment region is provided on the secondary cleavage line 51. However, since the secondary cleavage line 51 corresponds to the side surface of the semiconductor laser element 2, the cleavage line is used. There is little influence on the characteristics of the bend, and the cleavage distance is short and the bend is rare.
[0013]
FIG. 4 is a characteristic diagram showing a change in the variation of the remaining insulating film thickness after the insulating film removal treatment process and the bending amount of cleavage in the cleavage process in the present embodiment.
As can be seen from the figure, when the remaining thickness of the insulating film is 600 mm or less, variation in the amount of deviation from the scribe line is suppressed.
If the thickness of the insulating film other than the removal treatment region is 1000 mm, there is no problem in insulation.
[0014]
Embodiment 2. FIG.
FIG. 5 is a flowchart showing the semiconductor laser device manufacturing method according to the second embodiment of the present invention in the order of steps, and is particularly a method applied when manufacturing a semiconductor laser device to be soldered during mounting.
In the present embodiment, as the mounting method of a semiconductor laser device, when the die-bonding directly electrode of the semiconductor laser element by soldering or the like, in order to prevent short-circuiting of the non-insulated portion due to spread too much solder wettability, in FIG. 5, Prior to the insulating film forming step {(d) step}, at least in step (f), proton implantation {(c) step} is performed in the semiconductor layer under the region where the insulating film is to be removed to increase the electrical resistance. Otherwise, the semiconductor laser device is manufactured in the same manner as in the first embodiment.
[0015]
FIG. 6 is a semiconductor wafer schematically showing a cleavage state in the step of dividing the semiconductor wafer into which protons are implanted as described above into about 20 mm square as in the first embodiment and dividing it into semiconductor laser elements. 7 and 8 are cross-sectional views taken along the lines AA and BB in FIG. 6, and the dotted line in the drawing indicates the primary cleavage position .
That is, in the semiconductor wafer, the proton injection region 4 is formed in the region corresponding to the insulating film removal processing region 1 of the semiconductor layer composed of the n-type layer 10, the active layer 9, and the p-type layer 8 on the GaAs wafer 11. On top of this, an electrode layer 12 and a back electrode 13 are provided via an insulating film 3.
[0016]
Incidentally, the proton implantation, Rukoto applied to earthenware pots by partially overlap with the insulating film 3 is desirable. That is, when the proton implantation region 4 is diffused from the end face of the insulating film 3 at least by the diffusion thickness of the proton implantation region 4 below the insulating film 3, the electric resistance value becomes the same as that of the central portion of the proton implantation region 4 and the solder Even when the water spreads too much, leakage can be prevented.
As described above, also in this embodiment, since the insulating film in the region to be the cleavage portion is removed, the resistance is reduced with respect to the progress of cleavage as in Embodiment 1, and the cleavage is not caused. Bending can be suppressed and yield is improved.
As in the first embodiment , the cross-sectional view of the semiconductor laser element obtained by the primary cleavage and the secondary cleavage corresponds to the portion sandwiched between the dotted lines in FIG. 7, but as shown in FIG. This is a shape having a portion where the insulating film is thin (all removed in the figure).
[0017]
Embodiment 3 FIG.
In the method of manufacturing a semiconductor laser device according to the third embodiment of the present invention, as in the second embodiment, in the step of removing at least a part of the insulating film, the entire insulating film in the region to be the cleavage portion is removed. As shown in FIG. 9, in addition to providing a region where the removal process is performed and a region where all the insulating film is left without performing the removal process, as shown in FIG. A semiconductor laser device is manufactured in the same manner as in the second embodiment. It is to be noted that, as in the second embodiment, protons are injected into at least the semiconductor layer in the region corresponding to the region subjected to the removal treatment.
FIG. 9 is a plan view schematically showing a semiconductor wafer in which the insulating film is etched as described above in the present embodiment.
[0018]
FIG. 10 shows a semiconductor laser device obtained by dividing a semiconductor wafer partially subject to the removal process of the insulating film in the region to be cleaved as described above into about 20 mm square as in the first embodiment. FIG. 11 and FIG. 12 are cross-sectional views taken along lines AA and BB in FIG. 10, and are dotted lines in the drawing, schematically showing a cleavage state of the semiconductor wafer in a divided state. Indicates the primary cleavage position .
Also in this embodiment, since the insulating film in the region to be a cleavage portion is partially removed, the resistance to the progress of cleavage is reduced, and the cleavage line is prevented from bending as in the first embodiment. Improvement effect was obtained.
[0019]
Incidentally, Te embodiment odor, since the leakage current affects the properties, since the primary cleavage plane 5 is a laser light-emitting surface, an insulating film under the electrode layer, in this embodiment, the insulating film is removed a realm that does not perform the processing.
[0020]
Embodiment 4 FIG.
In the semiconductor laser device manufacturing method of the present embodiment, the resistance to the progress of cleavage is provided by providing a region of the semiconductor wafer where the film thickness is thinner than the insulating film other than the above region in the insulating film in the region to be the cleavage portion. Therefore, a semiconductor laser device is manufactured in the same manner as in the first embodiment except that the insulating film is formed in advance as described above in place of the insulating film removing process in the first embodiment.
That is, in the method of manufacturing the semiconductor laser device in the first embodiment, in the insulating film forming step, first, the region to be the thin insulating film is masked with a resist film, and then an insulating film having an appropriate thickness is formed. Then, the insulating film according to this embodiment is formed by removing the resist film and adding an insulating film over the entire surface.
Next, without performing the process of partially removing the insulating film in the first embodiment, an electrode layer is formed and cleaved in the same manner as in the first embodiment to manufacture a semiconductor laser device .
In the method of manufacturing the semiconductor laser device according to the present embodiment, as in the first embodiment, the cleavage line can be prevented from being bent and the semiconductor laser device can be prevented from being damaged, and the yield has been improved.
[0021]
【The invention's effect】
Method of applying a more Engineering of the present invention, a semiconductor layer laminated on the semiconductor wafer, an electrode layer provided via an insulating film on the semiconductor layer, and cleavage in the crystal direction of the semiconductor wafer, the plurality of semiconductor laser elements In the method for manufacturing a semiconductor laser device to be divided, an insulating film is provided on the semiconductor layer of the semiconductor laser device in the cleavage region in the cleavage for forming the light emitting surface of the semiconductor laser device, and the insulating film in the cleavage region is provided with the insulating film in the cleavage region. A region thinner than the thickness of the insulating film other than the region is provided to form the insulating film, the electrode layer is provided on the insulating film of the semiconductor layer of the semiconductor laser element in the cleavage region, and the end of the semiconductor wafer is formed. by cleavage of the above semiconductor wafer by applying a stress to the scribe line after scribe line, and to the light-emitting surface end portion through the insulating film electrode and the semiconductor layer is extended In the method of dividing the semiconductor laser device, is prevented bending cleavage line, there is an effect that the yield is improved.
[Brief description of the drawings]
FIG. 1 is a flowchart showing a method of manufacturing a semiconductor laser device according to a first embodiment of the present invention in order of steps.
FIG. 2 is a plan view schematically showing a semiconductor wafer in which an insulating film is etched in FIG.
FIG. 3 is a plan view of the semiconductor wafer schematically showing a cleavage state in the step of dividing the semiconductor wafer into semiconductor laser elements according to the first embodiment of the present invention.
FIG. 4 is a characteristic diagram showing a change in the variation of the remaining insulating film thickness after the insulating film removal treatment process and the amount of bending of the cleavage in the cleavage process according to the first embodiment of the present invention; .
FIG. 5 is a flowchart showing a semiconductor laser device manufacturing method according to a second embodiment of the present invention in the order of steps.
FIG. 6 is a plan view of a semiconductor wafer schematically showing a cleavage state in a step of dividing the semiconductor wafer into semiconductor laser elements according to the second embodiment of the present invention.
7 is a cross-sectional view taken along line AA in FIG.
8 is a cross-sectional view taken along line BB in FIG.
FIG. 9 is a plan view schematically showing a semiconductor wafer in a state where an insulating film is etched in a third embodiment of the present invention.
FIG. 10 is a plan view of a semiconductor wafer schematically showing a cleavage state in a step of dividing the semiconductor wafer into semiconductor laser elements according to the third embodiment of the present invention.
11 is a cross-sectional view taken along line AA in FIG.
12 is a cross-sectional view taken along line BB in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Insulating film removal process area | region, 2 semiconductor laser element , 3 insulating film, 4 proton implantation area | region, 5 cleavage line, 8 p-type layer, 9 active layer, 10 n-type layer, 11 semiconductor wafer, 12 electrode.

Claims (1)

In a method for manufacturing a semiconductor laser device, a semiconductor layer is laminated on a semiconductor wafer, an electrode layer is provided on the semiconductor layer through an insulating film, and the semiconductor layer is cleaved in the crystal direction of the semiconductor wafer to be divided into a plurality of semiconductor laser devices An insulating film is provided on the semiconductor layer of the semiconductor laser element in the cleavage region in the cleavage for forming the light emitting surface of the semiconductor laser element, and the insulating film in the cleavage region is thinner than the thickness of the insulating film other than the region The insulating film is formed by providing a region, the electrode layer is provided on the insulating film of the semiconductor layer of the semiconductor laser element in the cleavage region, and a scribe line is inserted into an end of the semiconductor wafer, and then the scribe line is formed. stress cleaved the semiconductor wafer by applying a minute semiconductor laser device and to the light-emitting surface end portion through the insulating film electrode and the semiconductor layer is extended The method of manufacturing a semiconductor laser device which is characterized in that.

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