Low-temperature source device capable of accurately controlling temperature and using method

Abstract

The low-temperature source device comprises a PN type semiconductor module, the hot end face of the PN type semiconductor module is connected with a water cooling circulation base, the cold end face of the PN type semiconductor module is provided with a heat conduction wire and a temperature-sensitive sensor, the heat conduction wire is connected with a heat conduction module, the PN type semiconductor module is connected with a power supply filtering module, and the power supply filtering module is connected with a temperature-sensitive sensor. The power supply filtering module and the temperature-sensitive sensor are both connected with the PID control module, the water-cooling circulation base is connected with the water-cooling machine, and the water-cooling machine and the PID control module are both connected with the control system. The low-temperature source device is small in size, easy to operate, low in cost and capable of achieving low-temperature control in the sample machining process of the ion beam equipment and effectively avoiding thermal damage to the sample.

Description

Technical Field

[0001] The present invention relates to the technical field of ion beam equipment, and in particular to a low-temperature source device with precise temperature control and a use method thereof. Background Art

[0002] The surface morphology and composition of materials are often characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). However, the surface of materials is usually exposed to the atmosphere and is easily oxidized and contaminated to form a film-like structure. Before SEM or TEM testing, its intrinsic surface needs to be presented, so sample surface treatment is required. Traditional mechanical grinding methods are used to prepare sample cross-sections, and the cross-sections inevitably have mechanical damage, scratches, and contamination caused by abrasives embedded in the sample. In a vacuum environment, ion beam equipment uses a positively charged ion beam to continuously bombard the target area of ​​the sample to prepare the sample surface. During the processing, the sample is in a state of continuous swinging or rotation, and a smooth cross-section without mechanical damage and surface contamination can be prepared, making the surface closer to the actual structure of the sample, which helps to improve the resolution and clarity of SEM / TEM images.

[0003] However, ion beam processing of samples is a slow processing method that often takes several hours or even overnight. It is also processed in a vacuum environment, which can potentially cause the local temperature of the sample processing area to rise, or even be too high, especially for temperature-sensitive materials, which can cause local thermal damage. In order to avoid thermal damage, ion beam equipment suppliers on the market equip ion beam equipment with liquid nitrogen refrigeration devices to provide a cold source, and transfer the low temperature of the cold source to the sample stage to keep the sample in a low temperature state. For example, the ion beam milling equipment of Fischione Instruments' Model 1061SEM Mill is based on liquid nitrogen refrigeration to achieve low temperature control.

[0004] The low temperature control method based on liquid nitrogen refrigeration requires the installation of a Dewar tank. The general Dewar tank has a volume of about 3 liters and can provide low temperature for about 4 hours. Then it needs to be filled with liquid nitrogen in time, or equipped with an automatic liquid nitrogen filling subsystem, which increases the cost and site space. Another point is that the temperature of liquid nitrogen is around -196 degrees Celsius, which will cause the temperature of the sample area to be too low or not the expected temperature. Therefore, this low temperature control method often requires the installation of a heating module near the sample stage, making the temperature control of the ion beam equipment more complicated. Summary of the invention

[0005] The present invention provides a low-temperature source device with precise temperature control and a method for using the low-temperature source device. The low-temperature source device is small in size, simple to operate, and low in cost. It can achieve low-temperature control during sample processing by an ion beam device and effectively avoid thermal damage to the sample.

[0006] The technical solution of the present invention is implemented as follows: a low-temperature source device with precise temperature control includes a PN-type semiconductor module, the hot end face of the PN-type semiconductor module is connected to a water-cooled circulation base, the cold end face is provided with a heat-conducting wire and a temperature-sensitive sensor, the heat-conducting wire is connected to the heat conduction module, the PN-type semiconductor module is connected to a power filter module, the power filter module and the temperature-sensitive sensor are both connected to a PID control module, the water-cooled circulation base is connected to a water cooler, and the water cooler and the PID control module are both connected to a control system.

[0007] Furthermore, the PN type semiconductor module includes a sealed box, in which a multi-layer array of PN type semiconductor chips is arranged. The top of the sealed box is a cold end face, and the bottom end is a hot end face. Both the cold end face and the hot end face are heat-conducting end faces, and the surrounding side walls of the sealed box are heat-insulating walls.

[0008] Furthermore, the heat conduction module includes two heat-conducting brushes arranged opposite to each other, the two heat-conducting brushes are connected by a spring, a heat-conducting block is arranged at the tail between the two heat-conducting brushes, a sample table clamping groove is arranged at the head, and the heat-conducting wire is connected to the heat-conducting block.

[0009] Furthermore, the heat conductive wire is a flexible heat conductive wire, such as copper stranded wire, etc. The heat conductive wire includes several columns, one end of each column of heat conductive wire is connected to the PN type semiconductor module through a screw, and the other end is connected to the heat conductive block through a screw.

[0010] Furthermore, positioning grooves are provided on both sides of the heat conducting block, the positioning grooves match the tail of the heat conducting brush, and the inner side of the tail of the heat conducting brush is embedded in the positioning grooves. By setting the positioning grooves, the contact area is increased, the heat conducting efficiency is improved, and the position of the heat conducting brush is limited.

[0011] Furthermore, the water cooling circulation base comprises a box body, a water inlet and a water outlet are arranged on the box body, and a spoiler baffle is arranged in the box body between the water inlet and the water outlet. By setting the spoiler baffle, the circulation path of water is increased and the heat conduction efficiency is increased.

[0012] Furthermore, the head of the thermal brush is made of graphite, and the tail is made of copper.

[0013] Furthermore, the sealed box and between the sealed box and the water-cooling circulation base are filled with thermally conductive silicone.

[0014] Furthermore, the heat conductive wires include two rows, and the temperature sensitive sensor is located at the center of the cold end surface and between the two rows of heat conductive wires.

[0015] A method for using a low-temperature source device with precise temperature control comprises the following steps:

[0016] (1) The water cooler is started by the control system, and the cold water enters the water cooling circulation base through the water cooler and reduces the temperature of the hot end surface of the PN-type semiconductor module. Then, the cold water returns to the water cooler for cooling and continues to enter the water cooling circulation base;

[0017] (2) starting the PID control module through the control system, controlling the target output current of the power filter module through the PID control module, and the power filter module outputs current to the PN-type semiconductor module to control the temperature of the cold end surface of the PN-type semiconductor module to form a cold source;

[0018] (3) The sample stage is connected to the heat conduction module. The cold source absorbs the heat at the sample stage through the heat conducting wire and the heat conduction module, so that the sample area maintains the required temperature.

[0019] Beneficial effects of the present invention:

[0020] The present invention is based on the Peltier effect and adopts an array PN-type semiconductor to construct a cold source. The target temperature of the cold source can be controlled by controlling the input current of the PN-type semiconductor module. The control method is simple and direct, and the occupied volume is small. The cold source can be directly placed in the vacuum chamber of the ion beam tool for use. The cold source is close to the sample stage, the low temperature conduction is fast, and the temperature control efficiency is high.

[0021] The temperature control of the cold source constructed by the PN-type semiconductor module adopts PID control, which is a mature and efficient method and can quickly achieve the control of the target temperature.

[0022] The cold source and the heat conduction module are connected by a flexible heat-conducting wire, which is convenient for disassembly, cleaning and maintenance.

[0023] The low temperature source device of the present invention is suitable for providing a cold source and a precise temperature-changing platform for related applications in a vacuum environment chamber, for example, it can provide temperature change or target temperature control for sample observation in a scanning electron microscope chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 It is a structural schematic diagram of a low temperature source device;

[0026] Figure 2 It is a top view of the heat conducting wire and the PN type semiconductor module;

[0027] Figure 3 It is a structural schematic diagram of the heat conduction module;

[0028] Figure 4 for Figure 3 A top view of

[0029] Figure 5 This is a split diagram of the heat conduction module;

[0030] Figure 6 Schematic diagram of the internal structure of the water-cooling circulation base.

[0031] PN type semiconductor module 1, power filter module 2, PID control module 3, control system 4, temperature sensitive sensor 5, thermal wire 6, heat conduction module 7, sample table 8, water cooling circulation base 9, sealed box 10, thermal brush 11, spring 12, thermal block 13, box body 14, water inlet 15, water outlet 16, first partition 17, second partition 18. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] like Figure 1 As shown, a low-temperature source device with precise temperature control includes a PN-type semiconductor module 1, which is connected to a power filter module 2, which is connected to a PID control module 3, which is connected to a control system 4. The control system 4 can adopt a PLC controller, such as model S7-1200, etc. The control system 4 controls the target temperature, start-up and shutdown states of the PID control module 3. The target temperature is set by the control system 4, and this temperature will be used as the target temperature of the PID control module 3.

[0034] The cold end surface of the PN type semiconductor module 1 is provided with a temperature sensor 5, which is connected to the PID control module 3. The PID control module 3 monitors the temperature of the cold end surface of the array PN type semiconductor module 1 in real time through the temperature sensor 5. The built-in microcontroller of the PID control module 3 calculates the current control signal to be output through the PID control algorithm according to the set target temperature and the current temperature difference to adjust the temperature. The microcontroller is used to control the current size and direction of the multi-layer array PN type semiconductor module 1 to ensure that the top plate temperature of the array PN type semiconductor module 1 is maintained at the target temperature to form a cold source.

[0035] like Figure 1 and 2As shown, the cold end face of the PN type semiconductor module 1 is connected to the heat conduction module 7 through the heat conducting wire 6, and the heat conduction module 7 is connected to the sample stage 8. The cold source can absorb the heat of the sample and the sample stage 8 through the heat conducting wire 6 and the heat conducting module 7, so that the sample area is kept at a low temperature or a required temperature. The PID control module 3 dynamically adjusts the control parameters according to the temperature feedback monitored in real time to keep the cold source at the set target temperature. The heat conducting wire 6 is made of thick copper stranded wire, so that a soft connection is formed between the array PN type semiconductor module 1 and the heat conducting module 7, which is convenient for later maintenance.

[0036] The hot end face of the PN-type semiconductor module 1 is connected to the water-cooling circulation base 9, which is connected to the water-cooling machine, which is connected to the control system 4, and the control system 4 controls the output water flow temperature, flow rate, start and shut down status of the water-cooling machine. After the water-cooling machine is started, cold water flows from the water-cooling machine into the water-cooling circulation base 9, absorbs the heat generated by the PN-type semiconductor module 1, leaves the water-cooling circulation base 9 after the temperature rises, and finally flows back to the water tank of the water-cooling machine. The cooled cold water flows into the water-cooling circulation base 9 again, taking away the heat generated by the PN-type semiconductor module 1. This process will continue to ensure that the temperature of the hot end face of the PN-type semiconductor module 1 is stable, thereby ensuring that the temperature of the processed parts remains within a preset or safe temperature range.

[0037] The method for using the low temperature source device comprises the following steps:

[0038] (1) The water cooler is started by the control system 4, and the cold water enters the water cooling circulation base 9 through the water cooler, and reduces the temperature of the hot end surface of the PN type semiconductor module 1, and then returns to the water cooler for cooling, and then continues to enter the water cooling circulation base 9;

[0039] (2) starting the PID control module 3 through the control system 4, controlling the target output current of the power filter module 2 through the PID control module 3, and the power filter module 2 outputs current to the PN-type semiconductor module 1 to control the temperature of the cold end surface of the PN-type semiconductor module 1, thereby forming a cold source;

[0040] (3) The sample stage 8 is connected to the heat conduction module 7. The cold source absorbs the heat at the sample stage 8 through the heat conducting wire 6 and the heat conduction module 7, so that the sample area maintains the required temperature.

[0041] When the low temperature source device is in use, the whole device can be directly placed in the sample compartment of the ion beam device, and the heat conduction module 7 and the water cooling circulation base 9 are fixed. The interface of the sample compartment is reserved with connection devices for water pipes and power lines.

[0042] When the low temperature source device is in use, the water cooling circulation base can also be installed outside the sample chamber, and the other parts are placed inside the sample chamber.

[0043] like Figure 1As shown, the PN-type semiconductor module 1 includes a sealed box 10, in which a multi-layer array of PN-type semiconductor chips is arranged. The number of array PN-type semiconductor chips, the number of layers and the temperature of the water-cooled circulation base 9 determine the minimum value of its temperature control, and the number of layers can be adjusted according to the target temperature of the cold source.

[0044] The surrounding side walls of the sealed box 10 are heat-insulating walls, and non-heat-conducting materials are used. The top and bottom ends of the sealed box 10 are both heat-conducting end surfaces, and a copper plate with high thermal conductivity can be used. The sealed box 10 is filled with heat-conducting silica gel, so that the copper plate and the array PN type semiconductor chip and the adjacent array PN type semiconductor chips are tightly fitted to achieve good thermal conductivity requirements.

[0045] like Figure 2-5 As shown, the top of the sealed box 10 is a cold end face, a fixing hole of the heat conducting wire 6 is reserved on the cold end face, and several rows of heat conducting wires 6, such as two rows of heat conducting wires 6, are arranged on the cold end face, and the temperature sensitive sensor 5 is located at the center of the cold end face and between the two rows of heat conducting wires 6, and one end of each row of heat conducting wires 6 is connected to the PN type semiconductor module 1 by a screw (the screw is connected to the fixing hole of the heat conducting wire 6), and the other end is connected to the heat conduction module 7. The bottom end of the sealed box 10 is a hot end face, and the hot end face and the water cooling circulation base 9 are filled with heat conducting silica gel to fit tightly.

[0046] The heat conduction module 7 includes two heat conduction brushes 11 arranged at intervals facing each other. The two heat conduction brushes 11 are connected by a spring 12 to ensure that the heat conduction brushes 11 are tightly fitted to the sample stage 8 to form a tight hug state. A heat conduction block 13 is arranged at the tail between the two heat conduction brushes 11. The heat conduction wire 6 is connected to the heat conduction block 13 by screws. Positioning grooves are arranged on both sides of the heat conduction block 13. The positioning grooves match the tail of the heat conduction brush 11. The inner side of the tail of the heat conduction brush 11 is embedded in the positioning groove, so that the heat conduction block 13 and the tail of the heat conduction brush 11 can be tightly fitted, increasing the contact area, improving the heat conduction efficiency, and limiting the position of the heat conduction brush 11.

[0047] The tail of the thermal brush 11 is made of copper and the head is made of graphite. The head between the two thermal brushes 11 is provided with a sample stage 8 clamping groove. The thermal brush 11 transfers the heat of the sample stage 8 to the thermal block 13, keeping the sample stage 8 at a low temperature or target temperature, thereby achieving low temperature control of the test sample processing area.

[0048] like Figure 6As shown, the water-cooling circulation base 9 includes a box body 14, on which a water inlet 15 and a water outlet 16 are provided, and a spoiler baffle is provided in the box body 14 between the water inlet 15 and the water outlet 16, and the spoiler baffle includes a first baffle 17 and a second baffle 18 which are alternately arranged, and the head of the first baffle 17 is spaced apart from the box body 14, and the tail is connected to the box body 14, and the head of the second baffle 18 is connected to the box body 14, and the tail is spaced apart from the box body 14, so as to extend the circulation path of the cold water, thereby improving the heat exchange efficiency.

[0049] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low temperature source device with precise temperature control, characterized in that: It includes a PN type semiconductor module, the hot end face of the PN type semiconductor module is connected to the water cooling circulation base, the cold end face is provided with a heat conductive wire and a temperature sensitive sensor, the heat conductive wire is connected to the heat conduction module, the PN type semiconductor module is connected to the power filter module, the power filter module and the temperature sensitive sensor are both connected to the PID control module, the water cooling circulation base is connected to the water cooler, and the water cooler and the PID control module are both connected to the control system.

2. A low temperature source device with precise temperature control according to claim 1, characterized in that: The PN type semiconductor module includes a sealed box, in which a multi-layer array of PN type semiconductor chips is arranged. The top of the sealed box is a cold end face, and the bottom is a hot end face. Both the cold end face and the hot end face are heat-conducting end faces, and the surrounding side walls of the sealed box are heat-insulating walls.

3. A low temperature source device with precise temperature control according to claim 1 or 2, characterized in that: The heat conduction module includes two heat conduction brushes arranged opposite to each other, the two heat conduction brushes are connected by a spring, a heat conduction block is arranged at the tail between the two heat conduction brushes, a sample table clamping groove is arranged at the head, and the heat conduction wire is connected to the heat conduction block.

4. The low temperature source device with precise temperature control according to claim 1, characterized in that: The heat conducting wire is a flexible heat conducting wire, and the heat conducting wire includes several rows. One end of each row of heat conducting wire is connected to the PN type semiconductor module through a screw, and the other end is connected to the heat conducting block through a screw.

5. The low temperature source device with precise temperature control according to claim 3, characterized in that: Positioning grooves are provided on both sides of the heat conductive block, the positioning grooves match the tail of the heat conductive brush, and the inner side of the tail of the heat conductive brush is embedded in the positioning grooves.

6. The low temperature source device with precise temperature control according to claim 1, characterized in that: The water cooling circulation base comprises a box body, on which a water inlet and a water outlet are arranged, and a spoiler baffle is arranged in the box body between the water inlet and the water outlet.

7. The low-temperature source device with precise temperature control according to claim 3, characterized in that: The head of the thermal brush is made of graphite and the tail is made of copper.

8. The low-temperature source device with precise temperature control according to claim 2, characterized in that: The sealed box and the space between the sealed box and the water cooling circulation base are filled with thermally conductive silicone.

9. A low temperature source device with precise temperature control according to claim 1 or 4, characterized in that: The heat conducting wires include two rows, and the temperature sensitive sensor is located at the center of the cold end surface and between the two rows of heat conducting wires.

10. A method for using the low-temperature source device for precise temperature control according to any one of claims 1 to 9, comprising the following steps: (1) The water cooler is started by the control system, and the cold water enters the water cooling circulation base through the water cooler and reduces the temperature of the hot end surface of the PN-type semiconductor module. Then, the cold water returns to the water cooler for cooling and continues to enter the water cooling circulation base; (2) starting the PID control module through the control system, controlling the target output current of the power filter module through the PID control module, and the power filter module outputs current to the PN-type semiconductor module to control the temperature of the cold end surface of the PN-type semiconductor module to form a cold source; (3) The sample stage is connected to the heat conduction module. The cold source absorbs the heat at the sample stage through the heat conducting wire and the heat conduction module, so that the sample area maintains the required temperature.

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