JP2008028139A - Method for manufacturing semiconductor chip, surface-emitting semiconductor laser, surface-emitting semiconductor laser array, optical scanning apparatus and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing semiconductor chips by which the number of chips obtained from one substrate is larger than ever before. <P>SOLUTION: A semiconductor laminate is composed of an off substrate (inclined substrate) which has a major surface (1 0 0) inclined by 15° in the direction of its crystal orientation [0 1 1] and several devices formed on it. It is cut along cutting lines which extend in the directions forming angles of 45° and 135° with the direction of cleavage, and is divided into several chips each of which has 9 devices. That is to say, the semiconductor laminate on which several devices are formed is cut in such a way that its cut surface may not include cleavage planes of the substrate. Accordingly, the size of chips is reduced and the number of chips obtained from one substrate can be increased in comparison with conventional methods. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a semiconductor chip, a surface emitting semiconductor laser, a surface emitting semiconductor laser array, an optical scanning device, and an image forming apparatus, and more particularly, a method for manufacturing a semiconductor chip using an inclined substrate, and the manufacturing The present invention relates to a surface emitting semiconductor laser and a surface emitting semiconductor laser array manufactured by the method, an optical scanning device using light from the surface emitting semiconductor laser or the surface emitting semiconductor laser array, and an image forming apparatus.

  A surface emitting semiconductor laser (VCSEL) has many advantages such as lower manufacturing costs and easier integration by arraying than an edge emitting semiconductor laser. Therefore, it is expected to be used in many fields such as optical communication, optical interconnection, and optical recording.

  In general, an n-type semiconductor multilayer mirror, a lower spacer layer, a multiple quantum well active layer, an upper spacer layer, a p-type semiconductor multilayer film on an n-type GaAs substrate (usually a 3 inch substrate or a 2 inch substrate) A semiconductor stacked body is manufactured by sequentially stacking reflecting mirrors and the like, and then etched in a direction perpendicular to the substrate to form a plurality of mesas. After selective oxidation, the side walls and the periphery of each mesa are covered with an insulator and then flattened with polyimide, and the upper electrode provided in the contact area on the upper surface of the mesa and the electrode pad are connected via wiring on the polyimide. Thus, a plurality of VCSEL chips are obtained. Thereafter, each chip is separated and packaged. In this manner, a large number of VCSELs for communication or writing can be obtained at a time. In this VCSEL, laser light is emitted from a light emitting surface opened on the upper surface of the mesa. Note that a VCSEL array is a chip in which a plurality of laser oscillation units each having a mesa structure are integrated.

  The separation of the VCSEL chip is mainly performed by a dicing method or a scribe method. The dicing method is a method of cutting along a dicing line by rotating a rotating blade mixed with diamond powder at a high speed. The scribing method is a method in which a scribe line (straight scratches, separation grooves) is formed on a substrate surface with a diamond cutter, and a break blade is pressed from the back side of the substrate and cleaved.

  In the separation by these methods, chipping may occur around the dicing line and the scribe line.

  Patent Document 1 discloses a manufacturing method in which a separation semiconductor layer having a predetermined pattern is formed in a boundary region of a chip and separation is performed using the separation semiconductor layer in order to perform wafer separation reliably and easily. ing. Patent Document 2 discloses a semiconductor device having means for stopping chipping in order to reduce damage to a functional part due to chipping during dicing.

  By the way, in VCSEL, in order to control polarization, a so-called off-substrate (tilted substrate) may be used. The off-substrate is, for example, a substrate in which the (1 0 0) main surface is inclined about 2 ° to 15 ° in the direction of the (0 1 1) plane.

JP 2002-299761 A JP-A-7-263380

  However, in the manufacturing method disclosed in Patent Document 1 and the semiconductor device disclosed in Patent Document 2, since the distance between adjacent chips and the distance between adjacent functional elements are wide, the chip can be removed from one substrate. There was an inconvenience that the number was small.

  As a result of repeating various experiments and the like, the inventors have found that the size of chipping differs depending on the cutting direction. As an example, FIG. 18A shows the relationship between the chipping size and the cutting direction when the surface of the substrate whose (1 0 0) plane is off (tilted) by 15 ° is diced. Here, as shown in FIG. 18B, the direction parallel to the orientation flat (0-1 1) plane is 0 °, and the angle is changed by 10 ° clockwise to 180 °. In addition, it has been found that there is a similar tendency in chip separation by the scribing method.

  The present invention has been made on the basis of the novel knowledge obtained by the inventors as described above, and a first object thereof is a semiconductor chip capable of increasing the number of chips taken from one substrate as compared with the prior art. It is in providing the manufacturing method of.

  A second object of the present invention is to provide a low-cost surface emitting semiconductor laser and a surface emitting semiconductor laser array.

  A third object of the present invention is to provide an optical scanning device that can accurately scan the surface to be scanned without increasing the cost.

  A fourth object of the present invention is to provide an image forming apparatus capable of forming a high-quality image without increasing the cost.

  According to a first aspect of the present invention, there is provided a step of laminating a plurality of semiconductor layers on a substrate whose principal surface is inclined to form a semiconductor laminate; and etching the semiconductor laminate to provide a plurality of element portions. Cutting the semiconductor stacked body on which the plurality of element portions are formed so that a cut surface does not include a cleavage plane of the substrate, each of which is at least one element of the plurality of element portions And a step of dividing the chip into a plurality of chips each having a portion.

  According to this, when each of the plurality of element portions is divided into a plurality of chips each having at least one element portion, the semiconductor laminate in which the plurality of element portions are formed has a cut surface that is a cleavage plane of the substrate. Since it is cut so as not to include it, the size of chipping can be made smaller than before. Therefore, the interval between adjacent chips can be made narrower than before, and as a result, the number of chips taken from one substrate can be made larger than before.

  According to a second aspect of the present invention, there is provided a surface emitting semiconductor laser manufactured by the semiconductor chip manufacturing method of the present invention.

  According to this, since it is manufactured by the semiconductor chip manufacturing method of the present invention, it is possible to reduce the cost.

  According to a third aspect of the present invention, there is provided a surface emitting semiconductor laser array manufactured by the semiconductor chip manufacturing method of the present invention.

  According to this, since it is manufactured by the semiconductor chip manufacturing method of the present invention, it is possible to reduce the cost.

  According to a fourth aspect of the present invention, there is provided an optical scanning device for scanning a surface to be scanned with a light beam, the light source unit having the surface emitting semiconductor laser of the present invention; and the light beam from the light source unit. A first optical scanning device comprising: deflection means for deflecting; and a scanning optical system for condensing the deflected light beam on a surface to be scanned.

  According to this, since the light source unit includes the surface-emitting type semiconductor laser of the present invention, it is possible to accurately scan the surface to be scanned without increasing the cost.

  From a fifth aspect, the present invention is an optical scanning device that scans a surface to be scanned with a plurality of light beams, the light source unit having the surface-emitting type semiconductor laser array of the present invention; A second optical scanning device comprising: deflection means for deflecting a plurality of light beams; and a scanning optical system for condensing the deflected light beams on a surface to be scanned.

  According to this, since the light source unit includes the surface-emitting type semiconductor laser array of the present invention, it is possible to accurately scan the surface to be scanned without increasing the cost.

  According to a sixth aspect of the present invention, there is provided at least one image carrier that scans a light beam including image information with respect to the at least one image carrier. An image forming apparatus comprising: an apparatus; and a transfer unit that transfers an image formed on the at least one image carrier to a transfer object.

  According to this, since at least one first optical scanning device of the present invention is provided, it is possible to form a high-quality image without increasing the cost.

  According to a seventh aspect of the present invention, at least one image carrier that scans a plurality of light beams including image information with respect to the at least one image carrier. An image forming apparatus comprising: an optical scanning device; and transfer means for transferring an image formed on the at least one image carrier to a transfer object.

  According to this, since at least one second optical scanning device according to the present invention is provided, it is possible to form a high-quality image without increasing the cost.

<< Semiconductor chip manufacturing method >>
Hereinafter, as an embodiment of a method for manufacturing a semiconductor chip of the present invention, a method for manufacturing a surface emitting semiconductor laser array of a 780 nm band will be described with reference to FIGS.

(1) A lower reflector 2, a lower spacer layer 3, an active layer 4, an upper spacer layer 5 and selective oxidation are formed on the n-GaAs substrate 1 by crystal growth using metal organic chemical vapor deposition (MOCVD). Semiconductor layers such as the layer 6 and the upper reflecting mirror 7 are sequentially stacked (see FIG. 1A). Hereinafter, a structure in which these semiconductor layers are stacked is also referred to as a “semiconductor stacked body”.

  As shown in FIG. 2A and FIG. 2B as an example, the n-GaAs substrate 1 has a (1 0 0) plane as the main surface, and the main surface has a crystal orientation [0 1 1]. This is an off-substrate (inclined substrate) inclined by 15 ° in the direction of. Here, the cleavage direction is the direction of crystal orientation [0 1 1] and the direction of crystal orientation [0 -1 -1].

The lower reflecting mirror 2 has 40.5 pairs of a low refractive index layer made of n-Al _0.9 Ga _0.1 As and a high refractive index layer made of n-Al _0.3 Ga _0.7 As. is doing. The optical thickness of each refractive index layer is λ / 4 where λ is the oscillation wavelength. In addition, a composition gradient layer (not shown) in which the composition is gradually changed from one composition to the other composition is provided between the low refractive index layer and the high refractive index layer in order to reduce electrical resistance. It has been.

The lower spacer layer 3 is a layer made of Al _0.6 Ga _0.4 As.

The active layer 4 has a quantum well layer made of Al _0.12 Ga _0.88 As and a barrier layer made of Al _0.3 Ga _0.7 As.

The upper spacer layer 5 is a layer made of Al _0.6 Ga _0.4 As.

  A resonance region is formed by the lower spacer layer 3, the active layer 4, and the upper spacer layer 5. The optical thickness of this resonance region is λ.

The upper reflecting mirror 7 has 24 pairs of a low refractive index layer made of p-Al _0.9 Ga _0.1 As and a high refractive index layer made of p-Al _0.3 Ga _0.7 As. Yes. In addition, a composition gradient layer (not shown) in which the composition is gradually changed from one composition to the other composition is provided between the low refractive index layer and the high refractive index layer in order to reduce electrical resistance. It has been.

  The selective oxidation layer 6 is a layer made of AlAs. Strictly speaking, the selective oxidation layer 6 is provided in the upper reflecting mirror 6 at a position away from the resonance region by an optical thickness λ / 4.

Here, trimethylaluminum (TMA), trimethylgallium (TMG), and trimethylindium (TMI) are used as the Group III material, and arsine (AsH ₃ ) gas is used as the Group V material. Further, carbon tetrabromide (CBr ₄ ) is used as a p-type dopant material, and hydrogen selenide (H ₂ Se) is used as an n-type dopant material.

(2) A photomask 8 is provided on the surface of the semiconductor stacked body (see FIG. 1B). As shown in FIG. 3 as an example, the photomask 8 is set so that cutting lines when dividing into a plurality of chips are straight lines extending in directions of 45 ° and 135 ° with respect to the cleavage direction. ing. Thereby, the semiconductor stacked body can be cut so that the cut surface does not include the cleavage plane of the substrate 1. Here, as an example, one chip has nine (3 × 3) element portions.

(3) A mesa shape is formed by dry etching using the photomask 8 as an etching mask (see FIG. 1C). An enlarged view of part of FIG. 1C is shown in FIG.

(4) The photomask 8 is removed (see FIG. 4A).

(5) The selectively oxidized layer 6 whose side surface is exposed by etching is heat-treated in water vapor to oxidize the surrounding area to an Al _x O _y insulating layer 10, and the element driving current path is not oxidized at the center. A current confinement structure limited to the AlAs region 9 is formed (see FIG. 4B). An enlarged view of part of FIG. 4B is shown in FIG.

(6) An insulating film 11 made of SiO ₂ is formed (see FIG. 4C).

(7) Open a window on the P-side electrode contact on the top of the mesa corresponding to the element portion (see FIG. 5A). Here, after applying the resist mask, the opening at the top of the mesa was exposed to remove the resist at that portion, and then the insulating film 11 was etched and opened with BHF. An enlarged view of part of FIG. 5A is shown in FIG.

(8) Flatten with polyimide 15 (see FIG. 5B). An enlarged view of part of FIG. 5B is shown in FIG.

(9) The p-side electrode 12 is formed by a lift-off method. Specifically, portions other than the electrode are masked in advance with a photoresist, and after the electrode material is deposited, ultrasonic cleaning is performed in a solution in which the photoresist such as acetone is dissolved. As the electrode material on the p side, a multilayer film made of Cr / AuZn / Au or a multilayer film made of AuZn / Ti / Au is used. The p-side electrode 12 has a window 13 in the center of the mesa, and laser light is emitted from this portion (see FIG. 5C). An enlarged view of part of FIG. 5C is shown in FIG.

(10) After the back side of the substrate 1 is polished to a substrate thickness of about 100 μm, the n-side electrode 14 is formed (see FIG. 6A). The n-side electrode 14 is a multilayer film made of AuGe / Ni / Au to obtain an ohmic contact. An enlarged view of part of FIG. 6A is shown in FIG.

(11) Each dicing line having a width W (see FIG. 6B) is cut with a dicing saw. Here, each dicing line has an angle of 45 ° and 135 ° with respect to the cleavage direction.

  As shown in FIG. 18A, when the cutting direction has angles of 45 ° and 135 ° with respect to the cleavage direction, the size of chipping falls within 5 μm. Therefore, in this embodiment, the width W of the dicing line is 20 μm (the width of the dicing blade) +10 μm (chipping of 5 μm on one side) = 30 μm. The dicing line width when the conventional cutting direction is parallel to the cleavage direction is 20 μm (width of dicing blade) +50 μm (25 μm chipping on one side) = 70 μm, and dicing when the cutting direction is orthogonal to the cleavage direction. The line width is 20 μm (dicing blade width) +10 μm (5 μm chipping on one side) = 30 μm.

That is, in this embodiment, one width of the dicing line can be made 40 μm narrower than the conventional one. When the size of one chip is about 800 μm × 800 μm, the chip area per one including the dicing line is 0.689 mm ² (= 830 μm × 830 μm) in this embodiment, It can be seen that it is about 5% smaller than the chip area of 0.722 mm ² (= 870 μm × 830 μm) when cutting in the conventional cleavage direction. In other words, a 5% increase in chips can be obtained from one substrate during mass production. In addition to the dicing method, the scribing method has this effect. Since the scribing method does not use a blade, the scribe line may be 10 μm (5 μm chipping on one side).

  As shown in FIG. 9, the polarization of the surface-emitting type semiconductor laser array 100 manufactured in this way is controlled. That is, the polarization direction of the light emitted from each element can be made uniform.

  By the way, when the main surface is a (1 0 0) plane and the main surface is not inclined, the emitted light is linearly polarized light, but the polarization direction is not stable. This is based on the symmetry of the crystal structure and the device structure itself. The optical gain of the active layer has anisotropy, and the optical gain increases as the crystal orientation changes from the (1 0 0) plane to the (0 1 1) plane. In the (1 0 0) plane orientation, there is no gain between orthogonal polarizations in the active layer itself. In this embodiment, since the off-substrate with the crystal orientation inclined from the (1 0 0) plane to the (0 1 1) plane is used, the polarization directions can be easily aligned.

  As described above, according to the manufacturing method of the present embodiment, the main surface is (1 0 0), and the main surface is inclined by 15 ° in the direction of the crystal orientation [0 1 1] (inclined substrate). ) Is cut along cutting lines extending in directions of 45 ° and 135 ° with respect to the cleavage direction, each of which has nine element portions. Divided into multiple chips. That is, the semiconductor stacked body in which a plurality of element portions are formed is cut so that the cut surface does not include the cleavage plane of the substrate 1. Therefore, the size of chipping is reduced, and the number of chips that can be taken from one substrate can be increased more than in the past. As a result, a surface emitting semiconductor laser array having excellent positional accuracy of each element portion can be realized at low cost.

  Further, according to the manufacturing method according to the present embodiment, since the substrate 1 is an off-substrate, the polarization directions of the laser beams emitted from the respective element portions can be aligned.

  The arrangement of the plurality of element units in one chip is not limited to the above embodiment, and may be an arrangement as shown in FIG. 10, for example. Free arrangement according to the application is possible.

  In the above-described embodiment, the case where the cutting line when dividing into a plurality of chips is a straight line extending in the direction of 45 ° and 135 ° with respect to the cleavage direction has been described, but the present invention is not limited to this. For example, as shown in FIG. 11, the cutting line when dividing into a plurality of chips may be a straight line extending in the direction of 30 ° and 90 ° with respect to the cleavage direction. Examples of the surface emitting semiconductor laser array at this time are shown in FIGS. In short, it may be cut so that the cut surface does not include the cleavage surface of the substrate 1. As shown in FIG. 18A, the cutting direction is preferably inclined by 20 ° or more with respect to the cleavage direction.

  Moreover, although the said embodiment demonstrated the case where the number of the element parts contained in one chip | tip was nine, it is not limited to this. For example, the number of element units included in one chip may be one. In this case, a surface emitting semiconductor laser having one light emitting part can be manufactured. Similarly, a surface emitting semiconductor laser array having 16 (4 × 4) element units included in one chip, a surface emitting semiconductor laser array having 40 (4 × 10) elements, and the like are similarly formed. Can be manufactured.

Further, in the above embodiment, the active layer 4 has been described with a barrier layer made of _Al 0.12 _{Ga 0.88} quantum well layer made of As and _Al 0.3 _{Ga 0.7} As, thereto Without limitation, for example, a three-layer GaInPAs quantum well layer having a compressive strain composition and a band gap wavelength of 780 nm, and a Ga _0.6 having a four-layer tensile strain lattice-matched with the GaInPAs quantum well layer An active layer having an In _0.4 P barrier layer may be used. At this time, (Al _0.7 Ga _0.3 ) _0.5 In _0.5 P having a wide band gap may be used as a cladding layer for confining electrons (a spacer layer in the above embodiment). Compared with the case where the clad layer is formed of AlGaAs, the band gap difference between the clad layer and the quantum well layer can be made extremely large.

  Further, in the above-described embodiment, as the n-GaAs substrate 1, a case has been described in which a main surface is (1 0 0) and an off substrate in which the main surface is inclined in the direction of the crystal orientation [0 1 1] is used. However, the present invention is not limited to this. For example, an off-substrate in which the main surface is (-1 0 0) and the main surface is tilted in the direction of crystal orientation [0 1 -1] or crystal orientation [0 -1 -1] may be used. .

  Moreover, although the said embodiment demonstrated the case where the inclination angle of the main surface in the n-GaAs substrate 1 was 15 degrees, it is not limited to this.

  Moreover, although the said embodiment demonstrated the case where the surface emitting semiconductor laser array 100 was a surface emitting semiconductor laser array of a 780 nm band, it is not limited to this.

  In the above embodiment, the MOCVD method is used as the crystal growth method. However, the present invention is not limited to this, and other crystal growth methods such as a molecular beam crystal growth method (MBE method) are used. You can also.

  In the case of manufacturing a semiconductor other than the surface emitting semiconductor laser, one substrate is obtained by cutting so that the cut surface does not include the cleavage plane of the substrate (for example, a III-V group compound semiconductor substrate). It is possible to increase the number of chips that can be taken from the conventional method.

<Image forming apparatus>
Next, an embodiment of the image forming apparatus of the present invention will be described with reference to FIG. FIG. 14 shows a schematic configuration of a laser printer 500 as an image forming apparatus according to an embodiment of the present invention.

  The laser printer 500 includes an optical scanning device 900, a photosensitive drum 901, a charging charger 902, a developing roller 903, a toner cartridge 904, a cleaning blade 905, a paper feeding tray 906, a paper feeding roller 907, a registration roller pair 908, and a transfer charger 911. , A static elimination unit 914, a fixing roller 909, a paper discharge roller 912, a paper discharge tray 910, and the like.

  The charging charger 902, the developing roller 903, the transfer charger 911, the charge removal unit 914, and the cleaning blade 905 are each disposed near the surface of the photosensitive drum 901. Then, with respect to the rotation direction of the photosensitive drum 901, the charging charger 902, the developing roller 903, the transfer charger 911, the static elimination unit 914, and the cleaning blade 905 are arranged in this order.

  A photosensitive layer is formed on the surface of the photosensitive drum 901. Here, the photosensitive drum 901 rotates clockwise (in the direction of the arrow) within the plane in FIG.

  The charging charger 902 uniformly charges the surface of the photosensitive drum 901.

  The optical scanning device 900 irradiates the surface of the photosensitive drum 901 charged by the charging charger 902 with light modulated based on image information from a host device (for example, a personal computer). As a result, a latent image corresponding to the image information is formed on the surface of the photosensitive drum 901 on the surface of the photosensitive drum 901. The latent image formed here moves in the direction of the developing roller 903 as the photosensitive drum 901 rotates. The configuration of the optical scanning device 900 will be described later.

  The toner cartridge 904 stores toner, and the toner is supplied to the developing roller 903.

  The developing roller 903 causes the toner supplied from the toner cartridge 904 to adhere to the latent image formed on the surface of the photosensitive drum 901 to visualize the image information. Here, the latent image to which the toner is attached moves in the direction of the transfer charger 911 as the photosensitive drum 901 rotates.

  Recording paper 913 is stored in the paper feed tray 906. A paper feed roller 907 is disposed in the vicinity of the paper feed tray 906, and the paper feed roller 907 takes out the recording paper 913 one by one from the paper feed tray 906 and conveys it to the registration roller pair 908. The registration roller pair 908 is disposed in the vicinity of the transfer roller 911, temporarily holds the recording paper 913 taken out by the paper feed roller 907, and the recording paper 913 is synchronized with the rotation of the photosensitive drum 901. It is sent out toward the gap between 901 and the transfer charger 911.

  A voltage having a polarity opposite to that of the toner is applied to the transfer charger 911 in order to electrically attract the toner on the surface of the photosensitive drum 901 to the recording paper 913. With this voltage, the latent image on the surface of the photosensitive drum 901 is transferred to the recording paper 913. The recording sheet 913 transferred here is sent to the fixing roller 909.

  In the fixing roller 909, heat and pressure are applied to the recording paper 913, whereby the toner is fixed on the recording paper 913. The recording paper 913 fixed here is sent to the paper discharge tray 910 via the paper discharge roller 912 and sequentially stacked on the paper discharge tray 910.

  The neutralization unit 914 neutralizes the surface of the photosensitive drum 901.

  The cleaning blade 905 removes toner remaining on the surface of the photosensitive drum 901 (residual toner). The removed residual toner is used again. The surface of the photosensitive drum 901 from which the residual toner has been removed returns to the position of the charging charger 902 again.

<Optical scanning device>
Next, the configuration and operation of the optical scanning device 900 will be described with reference to FIGS. 15 and 16.

  The optical scanning device 900 includes a light source unit 121, a coupling lens 122, an aperture 123, an anamorphic lens 124, a polygon mirror 125, a deflector side scanning lens 126, an image plane side scanning lens 127, a processing device 140, and the like. ing.

  As shown in FIG. 16, the light source unit 121 is a surface emitting semiconductor laser having 16 (= 4 × 4) element parts manufactured in the same manner as the manufacturing method of the surface emitting semiconductor laser array described above. The array 200 is provided and 16 light beams can be emitted simultaneously.

  The coupling lens 122 turns the plurality of light beams emitted from the light source unit 121 into weak divergent light.

  The aperture 123 defines beam diameters of a plurality of light beams from the coupling lens 122.

  The anamorphic lens 124 converts a plurality of light beams through the aperture 123 into parallel light in the main scanning direction and a light beam that is focused near the polygon mirror 125 in the sub-scanning direction.

  The plurality of light beams from the anamorphic lens 124 are respectively deflected by the polygon mirror 125, and then imaged by the deflector side scanning lens 126 and the image plane side scanning lens 127, and the secondary light beam on the surface of the photosensitive drum 901. Light spots are collected at positions separated from each other by a predetermined distance in the scanning direction.

  The polygon mirror 125 is rotated at a constant speed by a polygon motor (not shown), and with the rotation, the plurality of light beams are deflected at an equal angular velocity, and each light on the photosensitive drum 901 is transmitted. The spot moves at a constant speed in the main scanning direction.

  The processing device 140 generates image data based on image information from a host device (for example, a personal computer), and outputs a drive signal for the surface emitting laser array 200 corresponding to the image data to the light source unit 121.

  In the surface-emitting type semiconductor laser array 200, as shown in FIG. 16, the positional relationship of each element unit in the sub-scanning direction is equally spaced when a perpendicular is drawn from the center of each element unit in the direction corresponding to the sub-scanning direction. Therefore, it can be considered that the light source is arranged on the photosensitive drum 901 at equal intervals in the sub-scanning direction by adjusting the lighting timing. For example, when the size of each element portion is φ20 μm, the pitch in the direction corresponding to the main scanning direction is 40 μm, and the pitch in the direction corresponding to the sub-scanning direction is 40 μm, the interval C = 10 μm, and assuming that the magnification of the scanning optical system is 1, 2400 dpi (dot / inch) can be realized. Of course, if the number of element portions in the direction corresponding to the main scanning direction is increased, or the pitch in the direction corresponding to the sub-scanning direction is decreased to further reduce the interval C, the density can be further increased, and higher quality can be achieved. Printing is possible. Note that the writing interval in the main scanning direction can be easily controlled by the lighting timing of the light source.

  Therefore, according to the optical scanning device 900 according to the present embodiment, since the light source unit 121 includes the low-cost surface-emitting type semiconductor laser array 200, the upper surface of the photosensitive drum 901 is increased without increasing the cost. You can scan with density.

  In addition, the laser printer 500 according to the present embodiment includes the optical scanning device 900, and as a result, a high-definition image can be formed at high speed without increasing the cost.

  In the above embodiment, the case of the laser printer 500 as the image forming apparatus has been described. However, the present invention is not limited to this. In short, an image forming apparatus provided with the optical scanning device 900 can form a high-definition image at a high speed without increasing the cost.

  Even in an image forming apparatus that forms a color image, a high-definition image can be formed at a high speed by using an optical scanning device corresponding to the color image.

  In the above embodiment, the case where the surface-emitting type semiconductor laser array 200 has 16 (= 4 × 4) element portions has been described, but the present invention is not limited to this. For example, instead of the surface emitting semiconductor laser array 200, as shown in FIG. 17, 40 (= 4 × 10) element portions manufactured in the same manner as the manufacturing method of the surface emitting semiconductor laser array described above. A surface-emitting type semiconductor laser array 300 having the above may be used. In this case, 40 light beams can be emitted simultaneously, and the photosensitive drum 901 can be scanned at a higher density. By the way, the external dimension of the surface-emitting type semiconductor laser array 300 is 800 μm × 800 μm, and as described above, the number of chips that can be taken from one substrate is about 5% larger than the conventional one, so that the cost can be reduced. it can.

  In the above embodiment, when a plurality of light beams are not required, the light source unit 121 is replaced with the surface emitting semiconductor laser array 200. The surface emitting type having one element portion in one chip. You may have a semiconductor laser. Even in this case, the optical scanning device 900 can scan the photosensitive drum 901 with high accuracy without increasing the cost. The laser printer 500 can form a high-quality image without increasing the cost.

  As described above, according to the semiconductor chip manufacturing method of the present invention, it is suitable for increasing the number of chips that can be taken from one substrate as compared with the prior art. Further, the surface emitting semiconductor laser and the surface emitting semiconductor laser array of the present invention are suitable for cost reduction. Moreover, the optical scanning device of the present invention is suitable for accurately scanning the surface to be scanned without increasing the cost. The image forming apparatus of the present invention is suitable for forming a high-quality image without incurring an increase in cost.

FIGS. 1A to 1C are views (No. 1) for describing a method for manufacturing a surface-emitting type semiconductor laser array according to an embodiment of the present invention. FIG. 2A and FIG. 2B are diagrams for explaining an off substrate (an inclined substrate), respectively. It is a figure for demonstrating a cutting part. FIGS. 4A to 4C are views (No. 2) for describing the method for manufacturing the surface-emitting type semiconductor laser array according to the embodiment of the present invention. FIGS. 5A to 5C are views (No. 3) for describing the method for manufacturing the surface emitting semiconductor laser array according to the embodiment of the invention. FIGS. 6A and 6B are views (No. 4) for describing the method of manufacturing the surface emitting semiconductor laser array according to the embodiment of the invention. 7A is an enlarged view of a part of FIG. 1C, FIG. 7B is an enlarged view of a part of FIG. 4B, and FIG. FIG. 6 is an enlarged view of a part of FIG. 8A is an enlarged view of part of FIG. 5B, FIG. 8B is an enlarged view of part of FIG. 5C, and FIG. FIG. 7 is an enlarged view of a part of FIG. It is a figure for demonstrating the surface emitting semiconductor laser array manufactured by the manufacturing method of the surface emitting semiconductor laser array which concerns on one Embodiment of this invention. It is a figure for demonstrating the modification of the surface emitting semiconductor laser array manufactured by the manufacturing method of the surface emitting semiconductor laser array which concerns on one Embodiment of this invention. It is a figure for demonstrating the modification of a cutting part. It is a figure for demonstrating the surface emitting semiconductor laser array manufactured when it has a cutting part of FIG. It is a figure for demonstrating the modification of the surface emitting semiconductor laser array manufactured when it has a cutting part of FIG. It is a figure for demonstrating schematic structure of the laser printer which concerns on one Embodiment of this invention. It is the schematic which shows the optical scanning device in FIG. It is a figure for demonstrating the surface emitting semiconductor laser array contained in the light source unit in FIG. FIG. 16 is a diagram for explaining a modification of the surface emitting semiconductor laser array included in the light source unit in FIG. 15. 18 (A) and 18 (B) show the relationship between the chipping size and the cutting direction when the surface of the substrate whose main surface of (1 0 0) plane is off (tilted) by 15 ° is diced. It is a figure for demonstrating.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 100 ... Surface emitting semiconductor laser array, 121 ... Light source unit, 125 ... Polygon mirror (deflection means), 126 ... Deflector side scanning lens (a part of scanning optical system), 127 ... Image surface side scanning lens (Part of scanning optical system), 200 ... surface emitting semiconductor laser array, 300 ... surface emitting semiconductor laser array, 500 ... laser printer, 900 ... optical scanning device, 901 ... photosensitive drum (image carrier), 903 ... Developing roller (part of transfer means), 911 ... Transfer charger (part of transfer means), 913 ... Recording paper (transfer object).

Claims (12)

A step of laminating a plurality of semiconductor layers on a substrate whose main surface is inclined to form a semiconductor laminate;
Etching the semiconductor laminate to form a plurality of element portions;
The plurality of chips each having the plurality of element portions formed by cutting the semiconductor stacked body so that a cut surface does not include a cleavage plane of the substrate, each having at least one element portion of the plurality of element portions. A method of manufacturing a semiconductor chip comprising: The substrate has a (1 0 0) plane as a main surface, and the main surface is inclined in the direction of crystal orientation [0 1 1],
In the dividing step, the semiconductor stacked body is cut along a direction different from both the crystal orientation [0 1 1] direction and the crystal orientation [0 -1 -1] direction of the substrate. A method for manufacturing a semiconductor chip according to claim 1.   In the dividing step, cutting is performed along a direction that forms an angle of at least 20 ° with respect to both the crystal orientation [0 1 1] direction and the crystal orientation [0 -1 -1] direction. A method for manufacturing a semiconductor chip according to claim 2.   The method of manufacturing a semiconductor chip according to claim 1, wherein the substrate is a III-V group compound semiconductor substrate.   5. The method of manufacturing a semiconductor chip according to claim 1, wherein, in the dividing step, the semiconductor chip is divided into a plurality of chips each having one element portion.   5. The method of manufacturing a semiconductor chip according to claim 1, wherein in the dividing step, the semiconductor chip is divided into a plurality of chips each having at least two element portions.   A surface-emitting type semiconductor laser manufactured by the method for manufacturing a semiconductor chip according to claim 5.   A surface-emitting type semiconductor laser array manufactured by the method for manufacturing a semiconductor chip according to claim 6. An optical scanning device that scans a surface to be scanned with a light beam,
A light source unit comprising the surface-emitting type semiconductor laser according to claim 7;
Deflecting means for deflecting a light beam from the light source unit;
A scanning optical system for condensing the deflected light beam on a surface to be scanned. An optical scanning device that scans a surface to be scanned with a plurality of light beams,
A light source unit comprising the surface-emitting type semiconductor laser array according to claim 8;
Deflecting means for deflecting a plurality of light beams from the light source unit;
A scanning optical system that condenses the deflected light beams on a surface to be scanned. At least one image carrier;
10. The optical scanning device according to claim 9, wherein the at least one image carrier scans a light beam containing image information.
An image forming apparatus comprising: transfer means for transferring an image formed on the at least one image carrier to a transfer object. At least one image carrier;
The optical scanning device according to claim 10, wherein the at least one image carrier scans a plurality of light beams including image information;
An image forming apparatus comprising: transfer means for transferring an image formed on the at least one image carrier to a transfer object.