JPS61174690A - Setting method of die-bonding position of luminant semiconductor chip for semiconductor laser - Google Patents

Abstract

PURPOSE:To set a die-bonding position accurately, by applying a laser light to the front end face of a luminant semiconductor chip, by disposing one end of an optical fiber on the side of the rear end face of said chip, and by moving the semiconductor chip to a position at which an output detected by an optical detector is maximum. CONSTITUTION:A laser light is applied to the front end face of a luminant semiconductor chip 4 from a position setting semiconductor laser 12, and the semiconductor chip 4 on the top of a block 3 is adsorbed by a vacuum chuck capillary 11 and moved in the vertical and horizontal directions with respect to an axial line C. When a luminant portion in an active layer on the semiconductor chip 4 coincides with the axial line C passing through a fixed point 0 for reference of a stem 2, the laser light is transmitted to one end 15a of an optical fiber 15 through the luminant portion of the active layer, and the maximum output is detected by an optical output detector 16 located at the other end 15b of the fiber. By this method, the luminant semiconductor chip 4 is moved to a position at which the maximum output is detected by the optical output detector 16, and thus a die-bonding position can be set at a position at which the line of the optical axis of laser light transmitted from the semiconductor chip4 is aligned with the axial line C passing through the fixed point 0 as reference point of the stem 2.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a semiconductor laser with an external monitor photodiode that uses a light-emitting semiconductor chip to generate laser light, in which the light-emitting semiconductor chip is used as a block. The present invention relates to a method for setting a die bonding position when die bonding is performed.

[Conventional technology]

In general, an external monitor photodiode that uses a light-emitting semiconductor chip to generate laser light is a type semiconductor laser, and as shown in FIGS. When a light-emitting semiconductor chip 4 is die-bonded via a submount 5 to the upper surface of a block 3 protruding from a stem 2 equipped with a vibro for attachment to an electrical device, a laser beam from the light-emitting semiconductor chip is transmitted to the stem 2. It is necessary to set the position accurately so that the transmission is along the axis (C) passing through the reference fixed point (0) at 2.

In other words, if the optical axis of the laser light emitted by $1 from the light-emitting semiconductor chip is deviated from the axis (C) passing through the reference fixed point (0) in the stem 2, the semiconductor laser attached to the electrical equipment must be replaced. When replacing the semiconductor laser, the emission position of the laser beam may shift.
Each time it is replaced, it is necessary to adjust the position so that the laser beam emission position returns to its original position.

The outside of the block 3 with the light-emitting semiconductor chip 4 in the semiconductor laser l is covered with a cap 8 with a glass window 7 as shown by the two-dot chain line, and the P end is visible from the other side of the stem 2. KAζ Child 1a4 is prominent.

Therefore, conventionally, when die-bonding the light-emitting semiconductor chip 4 onto the upper surface of the block 3, the optical axis of the laser beam emitted from the light-emitting semiconductor chip 4 passes through the reference fixed point (0) on the stem 2 (C ) The following method was adopted to set the die bonding position of the light-emitting semiconductor chip 4 with respect to the block 3.

That is, as shown in FIG. 5, while the stem 2 with the block 3 is fixed to the holding jig 9, the block 3 is
An operator magnifies and visually observes the front end surface of the semiconductor chip 4 placed on the upper surface using a microscope 10, and determines that the external contour of the front end surface of the semiconductor chip 4 falls within a predetermined reference line. vacuum chuck capillary 11
The die bonding position is set by moving at the , and the die bonding is performed at the set position.

[Problem that the invention seeks to solve]

However, the light-emitting semiconductor chip 4 used in a semiconductor laser is formed into a multilayer crystal body having an active layer 4a in the middle, as shown in FIG. Laser light is emitted from the light emitting portion 4a' at the location of the stripe 4b in the layer 4a along the optical axis line extending in the longitudinal direction of the stripe 4b as shown by arrows (A) and (A'), The positional deviation of the stripe 4b with respect to the center of the width dimension (S) in the semiconductor chip 4, that is, the cleavage position accuracy, and the light emitting portion 4 from the bottom surface of the semiconductor chip 4.
The accuracy of the height dimension (H) up to 2' is based on the semiconductor chip 4.
There is considerable variation in manufacturing, and
There is also variation in the attachment position of the block 3 to the stem 2.

Therefore, the die bonding position of the semiconductor chip 4 with respect to the block 3 is determined by an operator magnifying the front end surface of the semiconductor chip 4 with the microscope 10 and visually observing the front end surface of the semiconductor chip 4 as in the conventional method, and checking the external contour of the front end surface of the semiconductor chip 4 according to a predetermined standard. Even if the block 3 is set to fall within the line, there is no space between the optical axis of the laser beam emitted from the semiconductor chip 4 and the axis (C) passing through the reference fixed point (0) in the stem 2.
The deviation inevitably occurs due to variations in the positional accuracy of the semiconductor chip 4 relative to the stem 2 and the cleavage position accuracy and height dimension (H) accuracy during the manufacturing of the semiconductor chip 4.
According to past results, the deviation of the optical axis from the axis (C) varies by about 50 microns for each product, and it is extremely difficult to reduce the variation among products to less than this, and it is difficult to It was necessary to adjust the mounting position each time the attached semiconductor laser was replaced.

The present invention provides a method for determining the die bonding position of the external monitor photodiode to the block of the light-emitting semiconductor chip in the semiconductor laser, the accuracy of the attachment of the block to the stem, and the cleavage position accuracy and height dimension during the manufacture of the semiconductor chip. (H) It provides a method that allows accurate setting regardless of variations in accuracy.

[Means for solving problems]

Therefore, in the present invention, the external monitor photodiode is not absorbed into the active layer of the light-emitting semiconductor chip with respect to the front end surface of the light-emitting semiconductor chip placed on the top surface of the block protruding from the stem of the semiconductor laser. A laser beam of a certain wavelength is irradiated along an axis passing through a reference fixed point of the stem of the semiconductor laser, while the other end is irradiated on the rear end surface of the light-emitting semiconductor chip at a position of an axis passing through the reference fixed point of the stem. One end of an optical fiber is arranged so as to be exposed to a photodetector, and the light-emitting semiconductor chip is moved to a position where the output detected by the photodetector is maximized.

[Action/effect of the invention]

In this way, when the light-emitting portion of the active layer of the light-emitting semiconductor chip does not coincide with the axis passing through the reference fixed point of the stem of the semiconductor laser, the laser light irradiated onto the front end surface of the semiconductor chip Because it is blocked by the optical fiber, it cannot reach one end of the optical fiber.
Although no light output is detected by the photodetector at the other end of the optical fiber, as the semiconductor chip moves, the light-emitting portion of the active layer of the light-emitting semiconductor chip coincides with the axis passing through the reference fixed point of the stem of the semiconductor laser. Then, the laser beam irradiated onto the front end surface of the semiconductor chip passes through the light emitting part of the active layer of the luminescent semiconductor chip and reaches one end of the optical fiber, and the output is detected by the photodetector at the other end of the optical fiber. At this time, the die bonding position of the light emitting semiconductor chip with respect to the block must be accurately set to a position where the optical axis of the laser light emitted from the light emitting semiconductor chip coincides with the axis passing through the reference fixed point of the stem. This is possible.

In this way, the present invention utilizes the fact that the laser light irradiated onto the front end face of the light-emitting semiconductor chip passes through the light-emitting portion of the active layer of the light-emitting semiconductor chip and reaches the optical fiber, thereby determining the die bonding position of the semiconductor chip. In setting the die bonding position, there are variations in the open position accuracy and height dimension (H) accuracy when manufacturing semiconductor chips as in the conventional method, and the mounting accuracy of the block on the stem is Since there is no variation in the die bonding position of the semiconductor chip, the variation in the die bonding position of the semiconductor chip is limited to a range of several microns, and the compatibility of the product is ensured. You can improve to the point where it is no longer necessary, and
Since the die bonding position of the semiconductor chip can be set instantaneously by maximizing the forward I force from the optical fiber, it has the effect of shortening the time required for setting.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings (FIG. 1).

In FIG. 1, reference numeral 2 denotes a metal stem equipped with a vibro for attaching the external monitor photodiode type semiconductor laser 1 to electrical equipment, and the stem 2 is attached to a holding jig 9. , and a metal block 3 for die-bonding the light-emitting semiconductor chip 4 protrudes from its front surface, and the light-emitting semiconductor chip 4 is mounted on the upper surface of the block 3 via a silicon submount 5. ing.

12 is for the front end surface of the light-emitting semiconductor chip 4,
A positioning semiconductor laser is shown for irradiating a laser beam with a wavelength that is not absorbed by the active layer of the light-emitting semiconductor chip 4 through a converging lens 13, and the positioning semiconductor laser 12 is the same as the positioning semiconductor laser. The optical axis of the laser beam emitted from the frame 12 is located on the axis (C) passing through the reference fixed point (0) in the frame 2. Note that 14 is an APC for applying current to the PN terminal in the position setting semiconductor laser 12.
This is a power supply circuit.

Further, 15 indicates an optical fiber, one end 15a of which is
The rear end surface of the light-emitting semiconductor chip 4 is arranged to be located on the axis (C) passing through the reference fixed point (0) in the stem 2, and the other end 15b is a light output device equipped with a photodiode or a photomultiplier. Detector 16
looking into the sky.

The laser beam irradiated from the position setting semiconductor laser 12 onto the front end surface of the light emitting semiconductor chip 4 causes the light emitting portion of the active layer of the light emitting semiconductor chip 4 on the upper surface of the block 3 to be located at the reference fixed point (0) of the stem 2. ), the optical fiber tS does not reach one end 15a at the rear end surface of the light-emitting semiconductor chip 4 because it is blocked by the semiconductor chip 4, and the optical fiber tS at the other end 15b of the optical fiber 15 Although the output detected by the optical output detector 16 is zero or a small value, the semiconductor chip 4 on the upper surface of the block 3 is attracted by the vacuum chuck capillary 11 and is moved vertically and horizontally with respect to the axis (C). When the light-emitting portion of the active layer of the light-emitting semiconductor chip 4 coincides with the axis (C) passing through the reference fixed point (0) of the stem 2, the laser beam irradiated onto the front end surface of the semiconductor chip 4 becomes light-emitting. The light passes through the light emitting portion of the active layer of the semiconductor chip 4 and reaches one end 15a of the optical fiber 15, and the highest output is detected by the light output detector 16 at the other end 15b of the optical fiber 15.

Therefore, by moving the light emitting semiconductor chip 4 until the maximum output is detected by the light output detector 16, the die bonding position of the light emitting semiconductor chip 4 can be changed to Since the optical axis line can be accurately set at a position matching the axis line (C) passing through the reference fixed point (0) of the stem 2, the light-emitting semiconductor chip 4 can be die-bonded to the block 3 in this state. It is.

In the above embodiment, the light-emitting semiconductor chip 4 is irradiated with laser light by the position setting semiconductor laser 12, but other laser light emitting means may be used instead of the position setting semiconductor laser 12. Needless to say, it's a good thing.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, FIG. 2 is an enlarged longitudinal sectional front view of a type semiconductor laser with an external monitor photodiode, and FIG. 3 is an mm-m perspective view of FIG. FIG. 4 is an enlarged perspective view of a light-emitting semiconductor chip, and FIG. 5 is a diagram showing a conventional method. 1... External monitor photodiode is type semiconductor laser, 2... Stem, 3... Block, 4...
...Light-emitting semiconductor chip, 9...Holding jig, 12
... Semiconductor laser for position setting, 15 ... Optical fiber, 16 ... Optical output detector.

Claims (1)

[Claims] (1) A laser with a wavelength that is not absorbed by the active layer of the light-emitting semiconductor chip is applied to the front end surface of the light-emitting semiconductor chip placed on the top surface of the block protruding from the stem of the externally attached semiconductor laser with a photodiode for monitoring. Light is irradiated along the axis passing through the reference fixed point of the stem in the semiconductor laser, while a photodetector is attached to the rear end surface of the light emitting semiconductor chip at the position of the axis passing through the reference fixed point of the stem. for a semiconductor laser, characterized in that one end of an optical fiber is arranged so as to look into the light, and the light-emitting semiconductor chip is moved to a position where the output detected by the photodetector is maximized. A method for setting the die bonding position of a light-emitting semiconductor chip.