Semiconductor laser inspection equipment

Abstract

A semiconductor laser element (2) is placed on a first heating and cooling device (1). A probe holder (4) is mounted on a second heating and cooling device (3). A measuring probe (8) is fixed to the end of the probe holder (4). A micro-motion stage (9) moves the second heating and cooling device (3) and the probe holder (4) so ​​that the end of the measuring probe (8) abuts against the semiconductor laser element (2). An inspection device (10) inputs an inspection signal to the semiconductor laser element (2) via the measuring probe (8).

Description

Technical Field

[0001] The present disclosure relates to a semiconductor laser inspection device and a semiconductor laser inspection method for detecting characteristics of a semiconductor laser element by bringing a probe into contact with the semiconductor laser element. Background Art

[0002] The cut semiconductor laser element is placed on a fixture equipped with a heating and cooling device, and the probe is brought into contact with it to perform a characteristic inspection. If the probe at room temperature is brought into contact with the heated or cooled semiconductor laser, the characteristics of the semiconductor laser element will change due to the temperature difference, resulting in measurement deviation. In view of this, a technology is proposed in which a probe is heated with a heating device to make it the same temperature as the wafer when inspecting a semiconductor wafer. In this way, it is possible to prevent heat from being taken away from the semiconductor wafer and suppress measurement deviation. In addition, it is possible to suppress the deformation of the probe when the probe contacts and stabilize the contact.

[0003] However, in the past, since the heating device was installed separately from the probe, the probe had to be heated again by the heating device after the inspection was performed. In view of this, an inspection device in which a heating device is installed on the probe has been proposed (for example, refer to Patent Document 1).

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 10-90345

[0005] If you want to cool the probe, you need to install a Peltier element on the probe. The size of a general Peltier element is 10mm×10mm or more. The size of the probe used in semiconductor inspection is generally 1mm in diameter and about 20 to 30mm in length. Therefore, there is no space to install a general Peltier element near the probe. In the case of a Peltier element smaller than this, it is difficult to lead out the coated wiring that allows current to flow to the Peltier element. Assuming that the probe is provided with a Peltier element, since the supporting components that support them generate heat, a cooling mechanism such as water cooling is also required. However, since only a hole with a diameter of about a few mm is opened in the supporting component, only a small amount of cooling water can pass through, so it cannot be fully cooled. Therefore, the probe cannot be cooled, and it is impossible to prevent the characteristics of the semiconductor laser element from changing when the probe is abutted. Summary of the invention

[0006] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide a semiconductor laser inspection device and a semiconductor laser inspection method that can prevent the characteristics of a semiconductor laser element from changing when a probe abuts against the semiconductor laser element.

[0007] The semiconductor laser inspection device involved in the present disclosure is characterized in that it comprises: a first heating and cooling device, which carries a semiconductor laser element; a second heating and cooling device; a probe holder, which is installed on the above-mentioned second heating and cooling device; a measuring probe, which is fixed to the end of the above-mentioned probe holder; a micro-motion stage, which moves the above-mentioned second heating and cooling device and the above-mentioned probe holder so that the end of the above-mentioned measuring probe abuts against the above-mentioned semiconductor laser element; and an inspection device, which inputs an inspection signal to the above-mentioned semiconductor laser element via the above-mentioned measuring probe.

[0008] In the present disclosure, a semiconductor laser element is placed on a first heating and cooling device, and a probe holder is installed on a second heating and cooling device. The first heating and cooling device and the second heating and cooling device can control the temperature not only at a high temperature side but also at a low temperature side, so that the temperature of the semiconductor laser element and the measuring probe can be close. Thus, the characteristics of the semiconductor laser element can be prevented from changing when the measuring probe is in contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a block diagram showing the semiconductor laser inspection device according to the first embodiment.

[0010] Figure 2 This is a block diagram showing a semiconductor laser inspection device according to the second embodiment.

[0011] Figure 3 Is magnification Figure 2 A side view of area A surrounded by a dotted line.

[0012] Figure 4 This is a block diagram showing a modified example of the semiconductor laser inspection device according to the second embodiment.

[0013] Figure 5 This is a block diagram showing a semiconductor laser inspection device according to a third embodiment.

[0014] Figure 6 Is magnification Figure 5 A side view of area A surrounded by a dotted line.

[0015] Figure 7 This is a block diagram showing a semiconductor laser inspection device according to a fourth embodiment.

[0016] Figure 8 This is a block diagram showing a semiconductor laser inspection device according to a fifth embodiment.

[0017] Fig. 9 This is a graph showing the time variation of the wavelength of the light emitted from the semiconductor laser element relative to the set temperature of the measuring probe.

[0018] Fig.10This is a block diagram for illustrating the semiconductor laser inspection method involved in embodiment 6.

[0019] Fig.11 This is a block diagram for illustrating the semiconductor laser inspection method involved in embodiment 7. DETAILED DESCRIPTION

[0020] A semiconductor laser inspection device and a semiconductor laser inspection method according to the embodiments will be described with reference to the drawings. The same reference numerals are given to the same or corresponding components, and duplicate descriptions may be omitted.

[0021] Implementation Method 1

[0022] Figure 1 1 is a block diagram showing a semiconductor laser inspection device according to Embodiment 1. A heating and cooling device 1 is a stage for mounting a semiconductor laser element 2. A probe holder 4 is mounted on a heating and cooling device 3. The heating and cooling devices 1 and 3 have Peltier elements and the like that can control the temperature not only on the high temperature side but also on the low temperature side.

[0023] The temperature sensor 5 is built into the heating and cooling device 1 to measure the temperature of the heating and cooling device 1. The temperature sensor 6 is built into the heating and cooling device 3 to measure the temperature of the heating and cooling device 3. In the present embodiment, the control unit 7 sets the temperatures of the heating and cooling devices 1 and 3 to the same value based on the measurement results of the temperature sensors 5 and 6.

[0024] The measuring probe 8 is fixed to the distal end of the probe holder 4. The fine motion stage 9 moves the heater cooler 3 and the probe holder 4 in the vertical direction and the horizontal direction to bring the distal end of the measuring probe 8 into contact with the semiconductor laser element 2 mounted on the heater cooler 1.

[0025] The inspection device 10 includes a signal generator 11, an LD driving power supply 12, and a bias tee 13. The modulated signal output from the signal generator 11 and the constant voltage output from the LD driving power supply 12 are coupled in the bias tee 13 to form an inspection signal. The inspection device 10 inputs the inspection signal to the semiconductor laser element 2 via the measuring probe 8. The semiconductor laser element 2 is driven by the inspection signal to perform a characteristic inspection of the semiconductor laser element 2.

[0026] In addition, when measuring at a temperature lower than room temperature (25°C), condensation may occur on the measuring probe 8 or the semiconductor laser element 2, which may cause a change in characteristic values ​​or a short circuit during measurement. Therefore, it is necessary to surround the entire device with a box made of acrylic acid or other materials and fill it with dry air or N2 to prevent condensation.

[0027] In this embodiment, the semiconductor laser element 2 is placed on the heating and cooling device 1, and the probe holder 4 is mounted on the heating and cooling device 3. Since the heating and cooling device 1 and the heating and cooling device 3 can control the temperature not only at the high temperature side but also at the low temperature side, the temperature of the semiconductor laser element 2 can be close to that of the measuring probe 8. Thus, the characteristics of the semiconductor laser element 2 can be prevented from changing when the semiconductor laser element 2 contacts the measuring probe 8.

[0028] In addition, the control unit 7 sets the temperature of the heating and cooling device 1 and the heating and cooling device 3 to the same value. By making the measurement probe 8 contact the semiconductor laser element 2 in this state to perform measurement, it is possible to prevent heat from flowing into or out of the semiconductor laser element 2 when the measurement probe 8 contacts. As a result, it is possible to prevent the characteristics of the semiconductor laser element 2 from changing and causing measurement deviation.

[0029] In addition, in the conventional inspection apparatus, it is necessary to move the measuring probe to the heating and cooling device to heat and cool the end of the probe each time a measurement is performed. In contrast, in the present embodiment, since the heating and cooling device 3 can heat and cool the measuring probe 8 via the probe holder 4, it is not necessary to move the measuring probe 8 for heating and cooling.

[0030] In addition, the conventional inspection device in which the measuring probe and the heater are integrated cannot control the temperature to the low temperature side. Moreover, the space for installing the cooling mechanism such as the Peltier element and water cooling cannot be ensured near the probe. In contrast, in this embodiment, the probe holder 4 is installed on the heating and cooling device 3. Thus, the heating and cooling device 3 can cool the measuring probe 8 via the probe holder 4.

[0031] In addition, since the measuring probe 8 passes a high frequency of several tens of GHz, impedance matching is required. Therefore, there is no freedom in the design of the probe of the measuring probe 8, and it is very difficult to extend the measuring probe 8 from the heating and cooling device 3 to the semiconductor laser element 2, and it is necessary to pass through the probe holder 4. Therefore, the temperature difference between the heating and cooling device 3 and the end of the measuring probe 8 can be reduced as much as possible to reduce the temperature difference between the semiconductor laser element 2. Therefore, as a material for the probe holder 4, copper, aluminum, etc. with a thermal conductivity higher than 200 [W / m·K] is preferably used.

[0032] Implementation Method 2

[0033] Figure 21 is a block diagram showing a semiconductor laser inspection device according to Embodiment 2. Instead of the heating and cooling device 1 of Embodiment 1, a semiconductor laser element 2 is placed on a thin metal plate 15 provided on a heat insulating material 14 for measurement. One end of a spring 16 is connected to the upper surface of the metal plate 15, and the other end of the spring 16 is connected to the lower surface of the probe holder 4. The spring 16 thermally couples the metal plate 15 and the probe holder 4. The other structures are the same as those of Embodiment 1.

[0034] Figure 3 Is magnification Figure 2 FIG. 1 is a side view of an area A surrounded by a dotted line. A spring support 17 is fixed to the upper surface of the metal plate 15 by means of screws or the like. The spring fixing member 18 is in contact with the lower surface of the probe holder 4. A spring fixing pin 19 is mounted on the spring fixing member 18. The spring 16 is mounted on the spring fixing pin 19. The spring 16 is firmly fixed to the spring fixing pin 19, and it is preferred that the outer shape of the spring fixing pin 19 is as close to the inner diameter of the spring 16 as possible in order to facilitate heat transfer. In a state where the spring 16 is mounted on the spring fixing member 18, the end of the spring 16 is inserted into the spring support 17. In this state, the probe holder 4 is placed on the spring fixing member 18.

[0035] Heat from the probe holder 4 needs to be transferred to the metal plate 15. Therefore, the spring 16, spring support 17, spring fixing pin 19 and spring fixing member 18 are preferably made of metal with a thermal conductivity higher than 200 [W / m·K], and preferably made of the same material to have the same linear expansion coefficient.

[0036] Since the spring fixing member 18 is not fixed to the probe holder 4, the measuring probe 8 can be moved not only in the height direction but also in the horizontal direction when the spring fixing member 18 is in contact with the probe holder 4. Considering the mobility, the contact part between the lower surface of the probe holder 4 and the spring fixing member 18 can be mirror-polished and lubricated. Considering the thermal conductivity, thermal conductive grease can also be applied to the contact part. In order to prevent the spring 16 from flying out laterally, it is preferred to deepen the depth of the spring support 17 so that a part of the spring fixing pin 19 is always in the state of entering the spring support 17.

[0037] In this embodiment, the probe holder 4 is mounted on the heater-cooler 3, and the spring 16 thermally couples the metal plate 15 to the probe holder 4. Therefore, by transferring heat from one heater-cooler 3 to the measuring probe 8 and the metal plate 15, the temperature of the semiconductor laser element 2 and the measuring probe 8 can be made close. Thus, the characteristics of the semiconductor laser element 2 can be prevented from changing when the measuring probe 8 is in contact.

[0038] Figure 4This is a block diagram showing a modified example of the semiconductor laser inspection device involved in Embodiment 2. Instead of the heat insulating material 14 of Embodiment 2, support pillars 20 are installed at the four corners of the lower surface of the metal plate 15. The lower surface of the metal plate 15 is hollow. The material of the support pillars 20 is preferably a material that is not easy to transfer heat, such as resin or ceramic. In this case, the above-mentioned effect can also be obtained.

[0039] Implementation 3

[0040] Figure 5 1 is a block diagram showing a semiconductor laser inspection device according to Embodiment 3. Instead of the heater cooler 3 of Embodiment 1, a probe holder 4 is installed on the heat insulating material 21. The micro-motion stage 9 moves the heat insulating material 21 and the probe holder 4 in the vertical direction and the horizontal direction. One end of the spring 16 is connected to the upper surface of the heater cooler 1, and the other end of the spring 16 is connected to the lower surface of the probe holder 4. The spring 16 thermally couples the heater cooler 1 and the probe holder 4. The other structures are the same as those of Embodiment 1.

[0041] Figure 6 Is magnification Figure 5 A side view of the area A surrounded by a dotted line. A spring fixing component 18 is fixed to the upper surface of the heating and cooling device 1 by means of screws or the like. A spring fixing pin 19 is mounted on the spring fixing component 18. The spring 16 is mounted on the spring fixing pin 19. The spring 16 is firmly fixed to the spring fixing pin 19, and it is preferred that the outer shape of the spring fixing pin 19 is as close to the inner diameter of the spring 16 as possible in order to facilitate heat transfer. The spring support 17 is in contact with the lower surface of the probe holder 4. In a state where the spring 16 is mounted on the spring fixing component 18, the end of the spring 16 is inserted into the spring support 17. In this state, the probe holder 4 is placed on the spring support 17.

[0042] It is necessary to transfer the heat from the heating and cooling device 1 to the measuring probe 8. Therefore, the spring 16, the spring support 17, the spring fixing pin 19, and the spring fixing member 18 are preferably made of metal with a thermal conductivity higher than 200 [W / m·K], and preferably made of the same material in order to have the same linear expansion coefficient. The probe holder 4 is made of metal with a thermal conductivity higher than 200 [W / m·K], and preferably has a smaller size than the second embodiment to reduce the heat capacity, so that heat can be easily transferred to the measuring probe 8.

[0043] Since the spring support 17 and the probe holder 4 are not fixed, the measuring probe 8 can be moved not only in the height direction but also in the horizontal direction when the spring support 17 is in contact with the probe holder 4. Considering the mobility, the contact part between the lower surface of the probe holder 4 and the spring support 17 can be mirror-polished and lubricated. Considering the thermal conductivity, thermal conductive grease can also be applied to the contact part. In order to prevent the spring 16 from flying out laterally, it is preferred to deepen the depth of the spring support 17 so that a part of the spring fixing pin 19 is always in the state of entering the spring support 17.

[0044] In this embodiment, the spring 16 thermally couples the heater-cooler 1 on which the semiconductor laser element 2 is mounted and the probe holder 4. Therefore, by transferring heat from the heater-cooler 1 to the measuring probe 8 via the spring 16 and the probe holder 4, the temperature of the semiconductor laser element 2 and the measuring probe 8 can be made close. Thus, it is possible to prevent the characteristics of the semiconductor laser element 2 from changing when the semiconductor laser element 2 abuts against the measuring probe 8.

[0045] Implementation 4

[0046] Figure 7 1 is a block diagram showing a semiconductor laser inspection device according to Embodiment 4. A temperature sensor 22 is attached to a hole provided in the probe holder 4 or the measuring probe 8. The temperature sensor 22 measures the temperature of the measuring probe 8.

[0047] Before starting the inspection of the semiconductor laser element 2, the temperature of the heating and cooling device 3 is pre-adjusted as follows. The control unit 7 sets the heating and cooling device 1 and the heating and cooling device 3 to the temperature T°C for product inspection and stabilizes them. In this state, the temperature sensor 6 measures the temperature of the heating and cooling device 3, and the temperature sensor 22 measures the temperature of the probe holder 4. The value obtained by subtracting the measured temperature of the temperature sensor 22 from the measured temperature of the temperature sensor 6 is set to α. The control unit 7 sets the temperature of the heating and cooling device 1 to T, and resets the temperature of the heating and cooling device 3 to T+α.

[0048] Thus, since the temperature of the measuring probe 8 becomes T°C, it can be consistent with the set temperature of the heating and cooling device 1 that sets the temperature of the semiconductor laser element 2. Therefore, the temperatures of the semiconductor laser element 2 and the measuring probe 8 can be made closer than in the first embodiment. The other structures and effects are the same as those in the first embodiment. In addition, since the temperature measured by the temperature sensor 22 is not used in the measurement, the temperature sensor 22 can be removed after the adjustment of the set temperature of the heating and cooling device 3 is completed.

[0049] Implementation method 5

[0050] Figure 81 is a block diagram showing a semiconductor laser inspection device according to Embodiment 5. A wavelength meter 23 for measuring the wavelength of light emitted from the semiconductor laser element 2 is added to the structure of Embodiment 1. Before starting inspection of the semiconductor laser element 2, the temperature of the heating cooler 3 is adjusted in advance as follows.

[0051] The temperature of the heating cooler 3 was changed from T-10°C to T+10°C in 1°C increments relative to the set temperature T of the heating cooler 1. At each temperature, the temporal variation in the wavelength of the light emitted from the semiconductor laser element 2 when in contact with the measuring probe 8 was measured. Fig. 9 This is a graph measuring the time variation of the wavelength of the emitted light of the semiconductor laser element relative to the set temperature of the measuring probe. The horizontal axis is the set temperature of the measuring probe 8. The vertical axis is the absolute value of the time variation of the wavelength of the emitted light of the semiconductor laser element 2 when the measuring probe 8 is abutted. The time variation of the wavelength draws a parabola with a minimum point.

[0052] Next, if the temperature at which the time variation of the wavelength becomes minimum is set to T', the temperature of the heating and cooling device 3 is changed from T'-1°C to T'+1°C in units of 0.1°C to obtain the time variation of the wavelength. The temperature T' at which the time variation of the wavelength becomes minimum is solved through this measurement. The control unit 7 sets the heating and cooling device 3 to the solved temperature T'.

[0053] When the heating and cooling device 3 is set to the temperature T", the time variation of the wavelength becomes extremely small, which means that the temperature of the semiconductor laser element 2 is consistent with that of the measuring probe 8. By performing the above adjustment, the temperature of the semiconductor laser element 2 and the measuring probe 8 can be close. As a result, the characteristics of the semiconductor laser element 2 can be prevented from changing when it abuts against the measuring probe 8.

[0054] Implementation 6

[0055] Fig.10 This is a block diagram for explaining the semiconductor laser inspection method according to Embodiment 6. A wavelength meter 23 for measuring the wavelength of the emitted light of the laser element placed on the metal plate 15 is added to the structure of Embodiment 2. Before starting the inspection of the semiconductor laser element 2, the temperature of the heating cooler 3 is pre-adjusted as follows.

[0056] A temperature setting laser element 24 whose relationship between wavelength and temperature is known in advance is placed on the metal plate 15. While changing the temperature of the heating and cooling device 3, the wavelength of the output light of the temperature setting laser element 24 is measured by a wavelength meter 23, and the temperature of the heating and cooling device 3 is fixed when the wavelength corresponds to the desired temperature.

[0057] After removing the temperature setting laser element 24 from the metal plate 15, the semiconductor laser element 2 is placed on the metal plate 15 while the temperature of the heating and cooling device 3 is fixed. Then, as in the second embodiment, the tip of the measuring probe 8 is brought into contact with the semiconductor laser element 2 to inspect the semiconductor laser element 2. Thus, it is possible to accurately match the temperature conditions for inspecting the semiconductor laser element 2. Other structures and effects are the same as those in the second embodiment.

[0058] Implementation 7

[0059] Fig.11 This is a block diagram for explaining the semiconductor laser inspection method according to Embodiment 7. A wavelength meter 23 for measuring the wavelength of the emitted light of the laser element mounted on the heating and cooling device 1 is added to the structure of Embodiment 3. Before starting the inspection of the semiconductor laser element 2, the temperature of the heating and cooling device 1 is pre-adjusted as follows.

[0060] A temperature setting laser element 24 whose relationship between wavelength and temperature is known in advance is placed on the heating and cooling device 1. While changing the temperature of the heating and cooling device 1, the wavelength of the output light of the temperature setting laser element 24 is measured by a wavelength meter 23, and the temperature of the heating and cooling device 1 is fixed when the wavelength corresponds to the desired temperature.

[0061] After the temperature setting laser element 24 is removed from the heating and cooling device 1, the semiconductor laser element 2 is placed on the heating and cooling device 1 while the temperature of the heating and cooling device 1 is fixed. Then, as in the third embodiment, the tip of the measuring probe 8 is brought into contact with the semiconductor laser element 2 to inspect the semiconductor laser element 2. Thus, the temperature condition for inspecting the semiconductor laser element 2 can be matched with high accuracy. Other structures and effects are the same as those in the third embodiment.

[0062] Description of Reference Numerals

[0063] 1...first heating and cooling device; 2...semiconductor laser element; 3...second heating and cooling device; 4...probe holder; 5, 6, 22...temperature sensor; 7...control unit; 8...measurement probe; 9...micro-motion table; 10...inspection device; 15...metal plate; 16...spring; 20...pillar; 23...wavemeter; 24...laser element for temperature setting.

Claims

1. A semiconductor laser inspection device, characterized in that: have: A first heating and cooling device is provided with a semiconductor laser element; a second heating and cooling device; A probe bracket is installed on the second heating and cooling device; A measuring probe is fixed to the end of the probe bracket; A micro-movement stage for moving the second heating and cooling device and the probe holder so that the distal end of the measuring probe abuts against the semiconductor laser element; an inspection device that inputs an inspection signal to the semiconductor laser element via the measuring probe; A wavelength meter for measuring the wavelength of the light emitted by the semiconductor laser element; as well as The control unit solves the temperature at which the time variation of the wavelength of the output light of the semiconductor laser element becomes extremely small when the measuring probe is abutted against the measuring probe when the temperature of the second heating and cooler is changed relative to the set temperature of the first heating and cooler, and sets the second heating and cooler to the solved temperature.

2. The semiconductor laser inspection device according to claim 1, characterized in that: The thermal conductivity of the probe holder is higher than 200 W / m·K.

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