CN100344982C - Test fixture in high frequency measuring chip of laser in structure of monocoplanar electrode - Google Patents

Abstract

The present invention relates to a test fixture in high frequency measuring chips of a laser in a structure of a mono-coplanar electrode, which is characterized in that the present invention comprises a plurality of flat plates for conductive bodies, wherein each flat plate for a conductive body is rectangular; the flat plates for conductive bodies are mutually stacked and welded to form a multi-step structure, and the drop height of the multi-step structure is different.

Description

High-frequency test fixture for measuring non-coplanar electrode laser chips

technical field

The invention belongs to the field of optoelectronic devices, and relates to a fixture for measuring a high-speed semiconductor laser chip of a non-coplanar electrode.

Background technique

As a device for generating optical signals, a high-speed light source is one of the most critical components in an optical fiber communication system. High-speed semiconductor lasers are the most important light sources in optical communication systems at present. The high-frequency performance of semiconductor lasers determines the transmission rate of optical communication systems to a certain extent, so it is very important to accurately measure the high-frequency characteristics of semiconductor lasers.

Most of the semiconductor laser chips have a cuboid structure, and the upper and lower surfaces are plated with metal electrodes, corresponding to the P pole and N pole of the laser diode. However, the current commercial high-frequency microwave probes are usually coplanar structures, and the two poles of the probe cannot directly contact the two poles of the chip at the same time. The usual method is to first press-weld the N pole of the chip on one electrode of a heat sink coated with a coplanar gold electrode, and then lead a gold wire from the P pole of the chip to the other electrode of the heat sink, so that the Coplanar electrodes on non-coplanar chips.

But this method has the following two deficiencies: First, because the chip response measured from the coplanar electrode of the heat sink will include the response of the parasitic elements introduced by the heat sink and the gold wire, and the influence of these parasitic elements is obvious, so the measurement is not accurate enough. To obtain the real response of the chip, it is necessary to do a series of calibrations on the measurement results to deduct the relevant influence, which makes the measurement more complicated; secondly, the process of bonding the chip and the gold wire increases the complexity of the measurement and the impact of the chip. The possibility of damage, and once the chip is bonded to the heat sink, it cannot be removed, which has caused great inconvenience to the actual work.

Contents of the invention

The purpose of the present invention is to provide a high-frequency test fixture for measuring non-coplanar electrode laser chips. With the aid of the fixture, the coplanar microwave probe can directly perform high-frequency measurement on non-coplanar electrode laser chips, avoiding the The original method adopts the deficiencies of heat sink and gold wire and pressure welding process.

The technical scheme that the present invention solves its technical problem is:

A high-frequency test fixture for measuring non-coplanar electrode laser chips according to the present invention is characterized in that it comprises:

A plurality of conductor plates, the conductor plates are rectangular, and the plurality of conductor plates are stacked and welded to form a multi-step structure;

The drop of the multi-step structure is not the same.

The material of the conductor plate is gold-plated glass ceramics.

The number of stages of the multi-step structure is 2 to 15.

Wherein said drop is from small to large or from large to small.

The step difference between two adjacent steps of the multi-step structure described therein is 5 μm.

Each step surface of the multi-step structure described herein is plated with a metal indium layer, and is manufactured with a corresponding step serial number.

The beneficial effect of this scheme is: through the conductor step structure, the N electrode of the semiconductor chip is turned to be substantially coplanar with its P electrode, thus avoiding the use of heat sinks and gold wires and their influence on measurement; multi-level steps with different drop The structure enables the fixture to adapt to the high-frequency characteristic measurement of laser chips of various thicknesses; the indium layer on the surface of the step structure enables the chip to maintain good contact with the test fixture without welding; the light-emitting surface of the chip can be as close as possible to the step structure of the fixture edge, which facilitates light coupling during testing.

Description of drawings

In order to further illustrate the technical content of the present invention, the following detailed description is as follows in conjunction with the embodiments and accompanying drawings, wherein:

Fig. 1 is the external view of the test fixture of this scheme;

Fig. 2 is the structural representation of this scheme test fixture;

Fig. 3 is a schematic diagram of the working process of the test fixture of this scheme.

1-10 in Figure 1 indicates the step number from low to high in the step structure of the test fixture; a and b in Figure 2 represent two gold-plated glass-ceramic plates that constitute the step structure respectively; 1 in Fig. 3 represents coplanar microwave Probe 2 represents the non-coplanar electrode semiconductor laser chip to be tested, which is placed on the fifth step of the test fixture.

Detailed ways

Please refer to shown in Fig. 1, a kind of high-frequency test fixture of measuring non-coplanar electrode laser chip of the present invention comprises:

A plurality of conductor plates 10, the conductor plates 10 are rectangular, and the plurality of conductor plates 10 are stacked and welded to form a multi-step structure 20; the material of the conductor plates 10 is gold-plated glass ceramics; the multi-step structure 20 is graded from 2 to 15;

The drop of the multi-step structure 20 is not the same; the multi-step structure 20 with different drop is from small to large or from large to small; the difference between two adjacent steps of the multi-step structure 20 is 5 μm ; Each step surface of the multi-step structure 20 is plated with a metal indium layer, and made with a corresponding step number.

Please refer to shown in Fig. 2, the manufacture sketch map of a kind of non-coplanar electrode semiconductor laser test fixture of the present invention, including:

Step 1. Make the conductor plate 10 with the glass-ceramic material, and plate the gold layer with a certain thickness on its surface. By controlling the grinding process of the glass-ceramic material and the gold-plating time, gold-plated glass-ceramic plates of different thicknesses are obtained;

Step 2. On the upper right corner of the upper surface of the finished gold-plated glass-ceramic conductor plate 10, make step serial numbers according to the order of thickness;

Step 3. Utilize welding technology to weld the fabricated two gold-plated glass-ceramic conductor plates 10 into a stepped structure in sequence. This constitutes a unit in the multi-step structure 20;

Step 4. Repeat the step structure described in structure 3 to form multiple steps, and plate a metal indium layer on the surface of each step.

Referring to Fig. 3, the working process of the present invention is:

1. According to the thickness data of the laser chip 2, determine which step it should be placed on for measurement. If the thickness of the laser chip is 108 μm, it should be placed on the fifth step;

2. Place the chip 2 on the side of the step as close to the edge as possible, so that the distance between the center of the P electrode and the step surface on the fifth step is smaller than the distance between the two needle tips of the coplanar microwave probe;

3. Use one pole of the coplanar high-frequency microwave probe 1 to press the P pole of the laser chip, and the other pole of the probe just presses the upper surface of the fifth step to measure the high-frequency characteristics of the laser. ; The obtained data is the accurate high-frequency characteristic data of the chip;

4. After completing the test of a chip, it can be removed. Repeat the process described in 1-3 to test other high-speed laser chips with different thicknesses.

The present invention stacks and welds glass-ceramic plates coated with a gold layer on the surface to form a multi-step structure, and converts the N electrode of the semiconductor laser chip to a position substantially coplanar with the P electrode through the drop of the steps, and places the chip on the On the stepped surface, the two poles of the coplanar microwave probe can contact the stepped surface and the P pole on the top of the chip respectively, so that the high-frequency characteristics of the chip can be directly measured; the thickness of each glass-ceramic plate is different, so the steps of each level have different For different heights, from the lowest step upward, the height of the step increases by 5 μm for each step up. In this way, when the drop of the lowest step is 80 μm and the total number of steps is 10, the drop of the highest step is 140 μm. This drop range can adapt to the thickness of most laser chips. Although the thickness of the chip may not be equal to the step difference, the difference between the two is at most 2.5 μm, and the general commercial coplanar microwave probe can bear this maximum error; each step surface is marked with a drop mark, which can be conveniently determined. It is most appropriate for a certain chip to be tested on which level of step; the surface of the step is coated with a certain thickness of metal indium layer, which can ensure good contact between the chip under test and the fixture, so that it can be measured without welding; The entire test fixture is a good conductor of heat and electricity, so it has little effect on high-frequency testing, and the measured high-frequency response is the accurate high-frequency performance of the chip.

Claims (6)

1, a kind of high-frequency test anchor clamps of measuring non-coplanar electrodes chip of laser is characterized in that, comprising:

A plurality of conductor plates, this conductor plate are rectangle, and these a plurality of conductor plates stack welding mutually and constitute many ledge structures;

The drop of these many ledge structures is all inequality.

2, the high-frequency test anchor clamps of the non-coplanar electrodes chip of laser of measurement as claimed in claim 1 is characterized in that, the material of wherein said conductor plate is gold-plated devitrified glass.

3, the high-frequency test anchor clamps of the non-coplanar electrodes chip of laser of measurement as claimed in claim 1 is characterized in that, the progression of wherein said many ledge structures is 2 to 15 grades.

4, the high-frequency test anchor clamps of the non-coplanar electrodes chip of laser of measurement as claimed in claim 1 is characterized in that, wherein said drop is ascending or descending.

5, the high-frequency test anchor clamps of the non-coplanar electrodes chip of laser of measurement as claimed in claim 4 is characterized in that, two adjacent step drops of wherein said many ledge structures differ 5 μ m.

6, the high-frequency test anchor clamps of the non-coplanar electrodes chip of laser of measurement as claimed in claim 4 is characterized in that, each step surface of wherein said many ledge structures is coated with the indium metal layer, and are manufactured with the respective step sequence number.

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