JPS63127444A - Production of optical head - Google Patents

Abstract

PURPOSE:To reduce the man-hour for assembling and to improve the attachment precision by cutting out a substrate from a mount after setting plural chip bars and prisms in parallel on the semiconductor substrate. CONSTITUTION:Plural chip bars 15 are set in the direction orthogonal to the lengthwise direction of chips 11, which are arranged in a grating and where photodetectors are preliminarily formed, on a silicon wafer 10 and are melt-fixed by heating, and plural bar-shaped prisms 16 are set in parallel. Chips 11 are cut out from the wafer 10 to obtain optical heads 1 where photodetectors 4, semiconductor chips 15a, and prisms 6 are mounted on semiconductor substrates 2. The process where small semiconductor chips 15 and prisms are cut and individually are positioned is unnecessary, and the man-hour for assembling is reduced and the attachment precision is improved.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for manufacturing an optical head, and more particularly, a method for manufacturing an optical head in which a photodetecting element, a laser semiconductor chip, and a prism are integrated on a flat conductor substrate. Regarding.

[Essentials of invention]

The method for manufacturing an optical head of the present invention includes forming a plurality of photodetecting elements on a semiconductor substrate, and then arranging a rod-shaped chip bar made of a plurality of laser semiconductor chips and a rod-shaped prism on the semiconductor substrate. This is to prevent variations in the positional accuracy of the mount components when cutting these at the same time to obtain an optical head consisting of a photodetecting element, a laser semiconductor chip, and a prism.

[Conventional technology]

2. Description of the Related Art Various structures have been proposed as optical heads for detecting bit information on CDs (compact discs) and the like. Figure 2 is a patent application filed by the applicant in 1986-3857.
5 shows a perspective view of the optical head proposed in No. 5.

In FIG. 2, (1) shows the optical head as a whole, and a first photodetector element (3) such as a PTN diode is located on the left half of the main surface of a rectangular silicon or other semiconductor substrate (2). form. This first photodetecting element (3) is, for example, two sets of three divided photodetecting elements (3a) and (3b).
Consisting of Historically, a second photodetector element (4) consisting of a PIN diode or the like for monitoring is formed on the right half of the main surface of the semiconductor substrate (2). A laser semiconductor chip (5
) is directly fixed to the semiconductor substrate (2) with solder or the like, and a prism (6) with a trapezoidal cross section is connected to the first photodetecting element (3).
is fixed on top. The surface (6a) of this prism (6) facing the light emitting point of the active layer of the laser semiconductor chip (5)
) is a transflective surface, and the surface (6b) in contact with the semiconductor substrate (2) other than the surface in contact with the photodetecting elements (3a) and (3b) and the surface opposite to the surface (6b) (6c)
are both reflective surfaces.

In the above configuration, the laser beam (7a) emitted from the active layer of the laser semiconductor chip (5) passes through the prism (6).
), the incident laser beam (7
The reflected light of the incident laser beam (7b) irradiated as b) and reflected by the disk is reflected from the surface (6a) of the prism (6).
The transmitted light is incident on the first photodetecting element (3a) of the first set, and is reflected here.
c) and enters the first second set of photodetecting elements (3b), where data corresponding to the focus of the disc is detected. Note that (7C) shows an output laser beam for monitoring that is emitted from the active layer opposite to the laser semiconductor chip (5).

A conventional example of a method for manufacturing such an optical head (1) will be explained with reference to FIG. In the process step of FIG. 3B, the silicon wafer (10) formed into a disk shape in FIG. In addition to forming the first and second photodetecting elements (3) and (4) shown in the figure, that is, PIN diodes, tin solder electrodes and bonding butts for fixing the laser semiconductor chip (5) are formed. It is done. Next, as shown in FIG. 3C, a plurality of laser semiconductor chips (5) processed into predetermined shapes are mounted on the tin solder electrode forming surface of the chip (11) of the silicon wafer (10). Historically, as shown in the third diagram, a silicon wafer (10) is heated at 300 degrees Celsius for about 5 seconds to separate a plurality of laser semiconductor chips (5) into respective chips (11) of the silicon wafer (10), which is a semiconductor substrate. ) directly fused to... In the next step, a plurality of prisms (6) formed to a predetermined size as shown in FIG. 3E are bonded onto the first photodetecting elements (3a) and (3b) formed for each chip. Next, the silicon wafer (10) is divided into one chip (11).
) is cut into a lattice pattern to form a semiconductor substrate @(
2) An integrated optical head (1) on which first and second photodetecting elements (3), (4), a laser semiconductor (5), and a prism (6) are arranged is completed. Next, as shown in Figure 3G, the optical head (1) is bonded to a printed circuit board (13) such as a flexible wire, and as shown in Figure 3 H, the external electrodes of the printed circuit board (13) and the chip (11) are formed. A wire such as a gold wire was bonded between the bonding bats.

[Problem that the invention seeks to solve]

According to the method of manufacturing an optical head with the conventional configuration described above,
Laser semiconductor chips (5) and prisms (6) that have been cut into predetermined shapes must be mounted on a plurality of chips (11) of a silicon wafer (10). For this purpose, not only is a process of cutting the laser semiconductor (5) and prism (6) required, but also an even smaller laser semiconductor chip (5) and prism (6) are placed on top of the small chip (11).
Since each chip must be positioned one by one when mounting, variations in mounting position accuracy will be avoided, and positioning must be performed within the (extremely short) dimensional width of the chip (11), increasing accuracy when mounting. I found the drawback that I couldn't do it.

The present invention was made in view of the above-mentioned drawbacks, and its purpose is to suppress variations in positional accuracy when parts are attached to a semiconductor substrate during optical head manufacturing, and to provide an optical head that can be attached with high precision. To provide a manufacturing method.

[Means for solving problems]

The optical head manufacturing method of the present invention includes a wafer (10) made of a semiconductor substrate (2) and a plurality of photodetecting elements (3), (4).
), and a plurality of rod-shaped chip bars (15) made of a plurality of laser semiconductor chips are arranged parallel to the arrangement direction of the plurality of photodetecting elements formed on this wafer (10), and A plurality of bar-shaped prisms (16) are disposed on the semiconductor substrate, a plurality of chip bars disposed thereon, and the bar-shaped prisms are simultaneously cut to form a photodetecting element,
ii) an optical head consisting of a laser semiconductor chip and a prism.

[Effect]

According to the present invention, since 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, variations in mounting precision are eliminated and manufacturing of an optical head is possible with a reduction in the number of steps. I can provide a method.

〔Example〕

Hereinafter, the method for manufacturing the optical head of the present invention will be described in detail with reference to the assembly process diagram of FIG. Note that parts corresponding to those in the conventional optical head assembly process shown in FIG. 3 are given the same reference numerals and redundant explanation will be omitted. The optical head of the present invention proposes an optical head manufacturing method for obtaining an optical head assembly similar to that shown in FIG.

In FIG. 1, the steps A and B in FIG. 1 are 3L21A,
This is the same as step B, and the photodetecting elements (3) and (4) consisting of the first and second PIN diodes are arranged in each of the plurality of chips (11) of the silicon wafer (10) as shown in FIG. It is formed. However, the laser semiconductor chip bar attachment electrode is formed in the shape of a chip bar. Now, looking at the silicon wafer (10), the photodetecting elements (3) and (4) are formed along the direction perpendicular to the longitudinal direction of the chips (11) patterned in a grid pattern. Diagram C
In the laser semiconductor chip bar mounting process shown in FIG. 1, a plurality of rod-shaped chip bars (
15) Mount. Here, the chip bar (15) has a length that is approximately the same as the diameter of the silicon wafer (10),
A plurality of laser semiconductor chips (or laser semiconductor active JN) are provided at positions equal to the pitch of lattice-shaped chips patterned on a silicon wafer.

For example, this chip bar has chips (11
This chip bar (15) is mounted on a chip bar electrode formed in a chip bar shape. In the step shown in the first diagram, the silicon wafer (10) is heated at 300 degrees Celsius for about 5 seconds, and the chip bar (15) is heated on the silicon wafer (10).
0) is firmly fused. Furthermore, as shown in FIG. 1E, a plurality of bar-shaped prisms (16) [length approximately equal to the diameter of the wafer] are placed parallel to the chip bar (15) and above the first photodetector element (3). Mount and place on a silicon wafer (1
0) When the three parts consisting of the chip bar (15) and the bar-shaped prism (16) mounted on the top are simultaneously cut into a grid pattern, a chip (11) consisting of one semiconductor substrate (2) is obtained as shown in Fig. 1F. ) on the first and second photodetector elements (3)
, (4) are formed, and a plurality of optical heads (1) having slightly longer laser semiconductor chips (15a) and prisms (6) mounted thereon can be formed at the same time. Figure 1 G, ■(
The die bonding and wire bonding processes shown in Figure 3 G and H
The process is exactly the same. According to such a manufacturing method, the process of cutting the three parts can be omitted, which not only improves the accuracy of parts attachment, but also makes it possible to detect defects in adhesion before they occur because dicing is performed after mounting and adhering the parts.

〔Effect of the invention〕

According to the method of manufacturing an optical head of the present invention, there is no need for the step of cutting the laser semiconductor chip (5) to the size of the laser semiconductor chip (5) and the step of cutting the prism (6) to the same size.
Not only can the unit price of these parts be lower, but compared to mounting a laser semiconductor chip (5) or prism (6) cut into small pieces on a wafer chip (11), a long bar-shaped chip bar ( 15) and the rod-shaped prism (16) can be positioned over a span determined by the diameter of the silicon wafer, so the positioning accuracy is greatly improved. Furthermore, it has the effect of significantly reducing the number of steps required to mount the laser semiconductor chip and prism.

[Brief explanation of the drawing]

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) are first and second photodetecting 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] A step of forming a plurality of photodetecting elements on a semiconductor substrate, and a plurality of rod-shaped chip bars made of a plurality of laser semiconductor chips arranged on the semiconductor substrate in parallel with the arrangement direction of the plurality of photodetecting elements. a step of arranging a plurality of bar-shaped prisms on the semiconductor substrate in parallel with the chip bars; and a step of simultaneously cutting the semiconductor substrate and the plurality of chip bars and prisms thereon. A method for manufacturing an optical head, comprising: obtaining an optical head comprising a photodetecting element, a laser semiconductor chip, and a prism.