JPH0810496B2 - Optical head manufacturing method - Google Patents

Description

The present invention relates to a method for manufacturing an optical head, and more particularly to a method for manufacturing an optical head in which a photodetector, a laser semiconductor chip and a prism are integrally integrated on a semiconductor substrate. .

[Outline of Invention]

The optical head manufacturing method of the present invention comprises forming a plurality of photodetecting elements on a semiconductor substrate, and then disposing a rod-shaped chip bar composed of a plurality of laser semiconductor chips and a rod-shaped prism on the semiconductor substrate. Then, when these are cut at the same time to obtain an optical head composed of a photo-detecting element, a laser semiconductor chip and a prism, the positional accuracy of the mount parts does not vary.

[Conventional technology]

Various types of optical heads have been proposed as optical heads for detecting pit information such as CDs (compact disks). FIG. 2 is a perspective view of the optical head previously proposed by the present applicant in Japanese Patent Application No. 61-38575.

In FIG. 2, (1) shows an optical head as a whole, and a first photo-detecting element (3) such as a PIN diode is provided at, for example, the left half position of the main surface of a semiconductor substrate (2) made of rectangular silicon or the like. To form. The first photodetector element (3) is composed of, for example, two sets of photodetector elements (3a) and (3b) divided into three. Further, a second photodetector element (4) including a PIN diode for monitoring is formed on the right half position of the main surface of the semiconductor substrate (2). The laser semiconductor chip (5) is directly fixed to the semiconductor substrate (2) with solder or the like between the first and second photodetecting elements (3) and (4), and the prism (6) having a trapezoidal cross section is provided. It is fixed on the photodetector element (3) of No. 1. The surface (6a) of the prism (6) facing the light emitting point of the active layer of the laser semiconductor chip (5) is a semi-transmissive reflective surface, and of the surface (6b) in contact with the semiconductor substrate (2). The surface (6c) facing the surface (6b) and the surface (6c) other than the surfaces in contact with the photodetectors (3a) and (3b) are both reflective surfaces.

In the above configuration, the laser beam (7a) emitted from the active layer of the laser semiconductor chip (5) is reflected on the semi-transmissive reflection surface (6a) of the prism (6), and is not shown on the optical disk via an objective lens, though not shown. Is irradiated as an incident laser beam (7b), and the reflected light of the incident laser beam (7b) reflected by the disk is transmitted through the surface (6a) of the prism (6) to form a first first set of photodetectors ( 3a)
The transmitted light reflected here is reflected by the surface (6c) of the prism (6) and is incident on the first second set of photodetectors (3b) to detect data corresponding to pits on the disk. Incidentally, (7c) shows an emission laser beam for monitoring emitted from the active layer opposite to the laser semiconductor chip (5).

A conventional example of such a method of manufacturing the optical head (1) will be described with reference to FIG. The silicon wafer (10) formed in the disk shape in FIG. 3A is divided into a plurality of grid-shaped chips (11) in the process step of FIG. First and second shown in the figure
The photodetectors (3) and (4), that is, the PIN diode, are formed, and tin solder electrodes and bonding pads for fixing the laser semiconductor chip (5) are formed. Next, as shown in FIG. 3C, a plurality of laser semiconductor chips (5) processed into a predetermined shape are mounted on the tin solder electrode forming surface of the chip (11) of the silicon wafer (10). Further, as shown in FIG. 3D, the silicon wafer (10) is heated at 300 ° C. for about 5 seconds to form a plurality of laser semiconductor chips (5) on each chip (11) of the silicon wafer (10) which is a semiconductor substrate. ) ... directly fused to.
In the next step, a plurality of prisms (6) each having a predetermined size as shown in FIG. 3E are adhered on the first photodetector elements (3a) and (3b) formed for each chip. Next, the silicon wafer (10) is cut into one chip (11) in a grid pattern, and one chip (11) is cut as shown in FIG. 3F.
The integrated optical head (1) in which the first and second photodetector elements (3) and (4), the laser semiconductor (5) and the prism (6) are arranged on the semiconductor substrate (2) constituting the ) Is completed. Next, as shown in FIG. 3G, the optical head (1) is die-bonded to the printed circuit board (13) such as a flexible wire, and the external electrodes of the printed circuit board (13) are connected as shown in FIG. 3H.
A wire such as a gold wire is bonded between the bonding pads formed on the chip (11).

[Problems to be solved by the invention]

According to the above-described conventional method of manufacturing an optical head, a laser semiconductor chip (5) and a prism (6) that have been cut into a predetermined shape must be mounted on a plurality of chips (11) of a silicon wafer (10). . Therefore, not only a step of cutting the laser semiconductor (5) and the prism (6) is required, but also a smaller laser semiconductor chip (5) and a prism (6) are individually mounted on the small chip (11). Since the mounting must be done while positioning, the mounting position accuracy varies, and the positioning must be performed within the span within the dimension width of the chip (11) (extremely short), so the mounting accuracy cannot be increased. was there.

The present invention has been made in view of the above drawbacks, and an object of the present invention is to suppress variations in positional accuracy when mounting components on a semiconductor substrate during manufacturing of an optical head, and to provide an optical head that can be mounted with high accuracy. It is to provide a manufacturing method.

[Means for solving problems]

The method of manufacturing an optical head according to the present invention comprises a wafer (10) made of a semiconductor substrate (2), a plurality of photodetector elements (3),
(4) is formed in a grid pattern, and a plurality of rod-shaped semiconductor chips made of a plurality of laser semiconductor chips are arranged parallel to the arrangement direction of the photodetection elements (3), (4) formed in a grid pattern on the wafer (10). A chip bar (15) is arranged, a plurality of rod-shaped prisms (16) are arranged in parallel with the chip bar (15), a wafer (10) and a plurality of chip bars (15) arranged on the wafer (10). The rod-shaped prism (16) is simultaneously cut into a lattice shape to obtain an optical head including a photodetector, a laser semiconductor chip, and a prism.

[Action]

According to the present invention, a rod-shaped chip bar and a rod-shaped prism are mounted on a semiconductor substrate and these three parts are cut at the same time, so that there is no variation in mounting precision, and a method of manufacturing an optical head capable of reducing the number of steps is provided. Can be provided.

〔Example〕

Hereinafter, the method of manufacturing the optical head of the present invention will be described in detail with reference to the assembly process diagram of FIG. The parts corresponding to those of the conventional optical head assembling process shown in FIG. The optical head of the present invention provides an optical head manufacturing method for obtaining an optical head assembly similar to that shown in FIG.

In FIG. 1, the steps of FIGS. 1A and 1B are shown in FIGS.
The same as the above process, the photodetector elements (3) and (4) composed of the first and second PIN diodes are formed as shown in FIG. 2 for each of the plurality of chips (11) of the silicon wafer (10). Has been done. However, the laser semiconductor chip bar attachment electrode is formed in a chip bar shape. Now, when viewed on the silicon wafer (10), the photo-detecting elements (3) and (4) are formed along the longitudinal direction of the chip (11) which is patterned in a lattice shape, so that it is shown in FIG. 1C. In the laser semiconductor chip bar mounting step, a plurality of rod-shaped chip bars (15) are mounted on a silicon wafer (10) in parallel with the direction orthogonal to the longitudinal direction of the chips (11). Here, the chip bar (15) has a length substantially the same as the diameter of the silicon wafer (10), and a plurality of laser semiconductor chips (or lasers) are arranged at a position equal to the pitch of lattice-shaped chips to be patterned on the silicon wafer. Semiconductor active layer). For example, this chip bar may be a GaAs substrate or the like on which laser semiconductors are formed at the lattice pitch of the chips (11) and cut out into a bar shape from the wafer. The chip bar (15) is formed in a chip bar shape. Mounted on the tip bar electrode. In the next step shown in FIG. 1D, the silicon wafer (10) is heated at 300 ° C. for about 5 seconds, and the chip bar (15) is firmly fused to the silicon wafer (10). Further, as shown in FIG. 1E, a plurality of rod-shaped prisms (16) [the length of which is approximately equal to the diameter of the wafer] are arranged in parallel with the chip bar (15) and on the first photodetecting element (3). When three parts, which are mounted and mounted on a silicon wafer (10), consisting of a chip bar (15) and a rod-shaped prism (16), are simultaneously cut into a grid pattern, as shown in FIG.
First and second photodetector elements (3) and (4) are formed on a chip (11) composed of two semiconductor substrates (2), and a rather long laser semiconductor chip (15a) and prism (6)
A plurality of optical heads (1) mounted with can be simultaneously formed. The die-bonding and wire-bonding steps shown in FIGS. 1G and H are exactly the same as the steps in FIGS. According to such a manufacturing method, the step of cutting the two parts can be omitted, and not only the accuracy of mounting the parts is improved, but also because the dicing is performed after mounting and bonding the parts, it is possible to detect a defective adhesion or the like. .

〔The invention's effect〕

According to the method of manufacturing an optical head of the present invention, since there is no step for cutting the size of the laser semiconductor chip (5) in advance and a step for cutting the prism (6) to the same small size, the unit price of these parts Not only is it possible to reduce the cost, but it is also possible to mount a laser-semiconductor chip (5) or prism (6) that is cut into small pieces on a wafer chip (11), compared with a long bar-shaped bar (15) Since the prism (16) can be positioned in a span determined by the diameter of the silicon wafer, the position mounting accuracy is greatly improved. Further, there is an effect that the number of steps for mounting the laser semiconductor chip and the prism can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a manufacturing process diagram of an optical head of the present invention, FIG. 2 is a perspective view of a conventional optical head, and FIG. 3 is a manufacturing process diagram of a conventional optical head. (1) is an optical head, (2) is a semiconductor substrate, (3),
(4) is the first and second light detecting elements, (5) is a laser semiconductor chip, (6) is a prism, (10) is a silicon wafer, (15) is a chip bar, and (16) is a rod-shaped prism. .

Claims (1)

[Claims] 1. A step of forming a plurality of photodetection elements on a wafer in a grid pattern, and a plurality of laser semiconductor chips parallel to the row or column direction of the photodetection elements arranged in a grid pattern on the wafer. Arranging a plurality of rod-shaped chip bars, arranging a plurality of rod-shaped prisms on the semiconductor substrate in parallel with the chip bars, and the semiconductor substrate and the plurality of chip bars and prisms on the semiconductor substrate. At the same time to obtain an optical head composed of a photo-detecting element, a laser semiconductor chip, and a prism, and manufacturing the optical head.