JP2012145283A - Heating device - Google Patents

Abstract

[PROBLEMS] To heat and measure an object even when the object is stage-operated without using a hermetic structure to measure the object with high accuracy while heating the object uniformly and uniformly. A heating device is provided.
A plate-type heater having an opening provided for measurement is arranged on the upper surface of an object, and a contact-type or non-contact-type heating unit is disposed on the lower surface of the object. A heating case 9 composed of a support 11 that supports the object 6 is mounted on a stage, and a heating apparatus that enables heating and measurement of the object 6 while performing the stage operation is configured.
[Selection] Figure 1

Description

  The present invention relates to a heating apparatus capable of observing an object and measuring a surface shape and the like during heating when the object is heated for reflow soldering or the like.

  There are many products or substances in industrial products that require high temperature heating in the production stage. For example, in an electronic circuit board used in precision equipment, high-temperature reflow heating is performed to melt a connection material such as a solder material for electrical connection when a semiconductor element or the like is surface-mounted.

  As a method of high-temperature reflow heating, a method in which hot air is circulated inside the heating device in a sealed state to heat it to a uniform atmospheric temperature, a method of heating using radiant heat such as an infrared heater, or both hot air and an infrared heater are used. Some are used together.

    Problems such as deformation of objects that occur during high-temperature reflow heating affect product quality and yield, so it is very important to understand the various characteristics of objects during high-temperature heating. is there.

  When an object is optically measured during high-temperature heating to grasp changes in the dimensions and shapes of each part, the conventional heating device, as shown in Patent Document 1, has a sealed structure to uniformly heat the object. In addition, it is necessary to provide an observation window using a transparent body such as glass in a part of the heating device. In that case, the optical measuring instrument is separated from the observation window so as not to be affected by heat, such as a double casing or double window with a heat insulating material sandwiched so that the external surface of the observation window or apparatus casing does not become high temperature. It is common to install.

JP 2009-123796

  However, when trying to optically measure an object with high accuracy, it is necessary to use a magnifying optical system such as a microscope, and such an optical system is generally placed very close to an observation target. Since it is necessary, it is impossible to install the measuring instrument away from the observation window as described above. Alternatively, a so-called double window provided with an air layer for the purpose of heat insulation so as not to bring the window to a high temperature cannot be installed because the distance from the observation object is consequently increased.

  As a countermeasure against such difficulties, there is a heat insulating device that does not use a sealed structure that requires an observation window, protects the optical measuring instrument with a thin transparent heat insulating structure, and can be installed close to the observation target It has been proposed in Japanese Patent Application No. 2009-209283 by the same inventors as the present invention.

  However, since it is not a sealed structure, heating with hot air is difficult, and heating using radiant heat has a temperature difference between the directly heated surface and the opposite surface, and there is a limit to heating uniformity.

  The problem to be solved by the present invention is the realization of a heating device that can uniformly heat an object without unevenness, and enables optical measurement simultaneously with the heating, without making the heating device a sealed structure.

  In order to solve the above problems, a support for fixing a heating object, a back surface heater for heating the back side of the observation surface of the heating object in contact or non-contact, the heating object and the support At least one axis moving stage for mounting and operating the backside heater, and a uniform temperature region spreading in a plane, and an opening for observing the heating object in a part of the uniform temperature region And a surface heater that heats the heating object in a non-contact manner from the observation surface front side by bringing the heating object close to the heating object.

  By operating the moving stage, the front and back surfaces of the heating object can be uniformly heated simultaneously while observing or measuring the entire heating object through the opening.

  At least one thermometer is installed for the heating object, and the temperature of the heating object is controlled by feedback control.

  A parallel flat transparent body having a thickness that does not affect the measurement of the optical measuring instrument is disposed in the observation opening.

  By comprising as mentioned above, it becomes possible to heat both surfaces of a target object evenly at a uniform temperature without using a heating mechanism as a sealed structure. In addition, a heating apparatus capable of performing high-precision measurement while bringing the optical measuring instrument close to the object simultaneously with heating can be realized.

It is the front view which showed the Example of this invention. It is the side view which showed the heating case part of the Example. It is sectional drawing which showed the plate heater part of the Example. It is the graph which showed the temperature profile of the target object by infrared heater heating. It is the graph which showed the temperature profile of the target object by infrared heater heating + plate heater heating.

  In the following, embodiments that are considered to be the best for concrete implementation of the present invention will be described.

  First, an example of an embodiment embodying the present invention will be described with reference to FIGS.

  The basic configuration includes an observation unit and a heating unit, and the observation unit insulates the optical system unit 2 of the optical measuring instrument 1 for observing the observation surface of the object 6 and the optical system unit 2. Insulator 3. Further, in this embodiment, the optical system unit 2 represents an objective lens, and the optical measuring instrument 1 has a role of observing and measuring the light entering the optical system unit 2 by forming an image on the camera.

  When the optical system unit 2 approaches and observes the object 6, the heat insulator 3 of the observation unit insulates that heat from the object 6 or heat from the plate heater 5 is transferred to the optical system unit 2. It has a function to do. The heat insulator 3 is required to be sufficiently thin in the optical path portion of the optical system unit 2 than the working distance, and to have a transparent heat insulating structure that does not deteriorate the optical performance of the optical system unit 2.

  The heating unit includes a plate heater 5 that heats the object 6 from the observation surface side, a heat insulating material 4 that is attached to the plate heater 5, and a heating case 9. The heat insulating material 4 and the plate heater 5 are provided with a partial opening 10 in order to secure the optical path and insertion of the optical system unit 2 equipped with the heat insulator 3.

  The heating case 9 includes an infrared heater 7 that heats the object 6 from the back side of the observation surface, a heater insulating material 8 that is disposed under the heater, and a support portion 11 that supports the object 6. The heating case 9 is mounted on the XY stage 101 and can move in the XY direction. Further, a cooling fan 201 is provided on the side surface so that the object 6 can be forcibly cooled after heating.

  A plurality of infrared heaters 7 are arranged in the heating case 9 in accordance with the size of the object 6 as shown in FIG. In addition, in order to prevent heat from the infrared heater 7 from being transmitted to the XY stage 101 through the heating case 9, a heater heat insulating material 8 made of a low thermal conductivity material is disposed on the lower surface of the infrared heater 7. If the material of the support part 11 that supports the object 6 is expanded by heating, it becomes an error factor when the object 6 is measured. good. Here, although the infrared heater 7 is used to heat the object 6 from the back side of the observation surface, the present invention is not limited to this. The case where the object 6 is directly placed and heated like a hot plate type heater is also within the scope of the present invention. However, in this case, the object 6 also moves simultaneously due to the expansion and contraction of the heating unit, so it is necessary to suppress the expansion and contraction amount of the heating unit to such an extent that the observation and measurement are not affected.

  When heating is performed with the infrared heater 7 designed for heat distribution, the back side of the observation surface of the object 6 can be heated at a uniform temperature. Further, since the heating case 9 is not in contact with the plate heater 5, the XY operation can be performed together with the heating case 9, and an arbitrary position of the object 6 can be moved directly below the opening 10. That is, it is possible to observe an arbitrary portion of the object 6 while maintaining the positional relationship between the infrared heater 7 and the object 6.

  However, only by heating the infrared heater 7 from the back side of the observation surface, in addition to the time required for thermal equilibrium from the back side of the observation surface to the front side inside the target object 6, heat transfer from the front side of the target object 6 to the atmosphere leads to the target object. Thus, there is a temperature difference between the back side and the front side.

  Therefore, a mechanism is employed in which heating is performed by the plate heater 5 from the front side of the observation surface simultaneously with the infrared heater 7 from the back side of the observation surface. By arranging the distance between the object 6 and the plate heater 5 at a very close position of about 1 to 2 mm, the heating can be efficiently performed, and the plate heater 5 serves as a lid and is in a state close to a sealed structure. . Further, in order to cause the heating case 9 to perform the XY operation, the plate heater 5 needs an area that covers the operating range of the heating case. The object 6 is also heated from the front side of the observation surface by the plate heater 5 to stabilize the ambient temperature on the surface side and to prevent the release of heat into the atmosphere. The graph of the result verified in the present embodiment shown in FIG. 4.5 shows that the temperature difference between the back surface and the front surface side of the object 6 is greatly improved by the plate heater 5.

The plate heater 5 needs to be sufficiently thinner than the working distance of the optical system unit 2 at least in the region where the optical system unit 2 is inserted. In the present embodiment, as shown in FIG. 3, the plate heater unit is configured by sandwiching the heater 302 with a heat insulator 301 for heater and a copper plate 303. Only the thickness of the copper plate 303 is related to the working distance by arranging the heater 302 at a position where it does not interfere so that the optical system unit 2 can be inserted.

  In the case of the structure as described above, temperature unevenness occurs between the portion that is in contact with the heater 302 and the portion that is not in contact with the copper. However, as in this embodiment, copper having very good thermal conductivity among metals. By using the material, the temperature unevenness becomes minute. Furthermore, if the thickness of the copper plate 303 is reduced, the time to reach the thermal equilibrium state is shortened, and the working distance of the optical unit 2 can be easily ensured. Here, if there is a heater that is very thin and has a high power density, the same effect as described above can be obtained even if it is disposed over the entire heating area including directly under the optical system section 2, but this is also within the scope of the present invention. is there.

Furthermore, in the above case, a method of heating by applying hot air to the surface of the observation surface of the object 6 can be considered. However, when optical measurement is performed, if there is a gas fluctuation, the refractive index of the space changes and measurement noise is added to the measurement accuracy. May have an effect. Therefore, it is desirable that the optical path is in a laminar flow state. It is difficult to create a laminar airflow in a state where the object 6 is XY-operated instead of a sealed structure as in this embodiment.
Moreover, there is a possibility that hot air hits the object 6 directly and the object 6 is shaken to affect the measurement. If the object 6 can be fixed by a strong fixing method, the shaking is reduced. However, if the object 6 is heated while applying a strong external force to the object 6, thermal stress is generated during the heating, and thermal deformation becomes a problem.
Also in the verification experiment in the present embodiment, it is confirmed that the state of deformation during heating changes depending on the method of fixing the object 6.

  In the opening 10 of the plate heater 5, it is conceivable that the ambient temperature is lower than that immediately below the plate heater 5. Even in the verification of this example, a slight temperature decrease was observed with time. However, this is a level that does not cause a problem when measuring at high speed.

  In the case of the present embodiment, since the atmospheric temperature on the front side and the back side of the observation surface of the object 6 is more stable for the above reasons, the temperature control of the infrared heater 7 is controlled to the back surface temperature of the observation surface of the object 6. It is good to do for it. When temperature control is performed on the front side, the amount of operation increases in order to suppress disturbance, and a temperature difference between the two sides is easily made. In addition, the plate heater and the infrared heater usually have a higher heating rate than the infrared heater, so that the object 6 is greatly affected by the output of the infrared heater 7. In this case, if the front side is controlled to the target temperature, the back side temperature may be instantaneously higher than the target temperature (front side temperature) and may exceed the allowable temperature of the object 6.

  On the other hand, the structure which arrange | positions a parallel plane transparent body in the opening part 10 of the plate heater 5 can be considered. By disposing the parallel plane transparent body, the parallel plane transparent body is heated to become a high temperature body, and a decrease in the ambient temperature around the opening 10 is reduced. At this time, if the parallel plane transparent body has a thickness, the imaging performance of the optical system unit 2 is deteriorated due to its own thickness or deformation due to thermal expansion. If a material with little thermal expansion, such as synthetic quartz glass, is used, the influence on the measurement can be reduced. These cases are also within the scope of the present invention.

  The size required for the opening 10 of the plate heater 5 is determined by the distance between the numerical aperture of the optical unit 2 and the opening 10 of the plate heater 5, but as described above, the ambient temperature decreases in the opening 10. Because it happens, it is better to be as small as possible. Further, when a thin parallel plane transparent body is disposed in the opening 10 as described above, a thin and large parallel plane transparent body is not preferable because it is very difficult to handle and difficult to manufacture. In addition, deflection may occur due to its own weight, and as a result, optical performance may be affected.

According to the present invention, it is possible to heat the front and back surfaces of an object with a uniform temperature distribution without heating in an enclosed space. At the same time, precise shape observation and measurement of the object being heated are possible.
This is considered to be in great demand in the field of studying the effects of high temperature stress on objects.

DESCRIPTION OF SYMBOLS 1 Optical measuring device 2 Optical part 3 Heat insulator 4 Heat insulating material 5 Plate heater 6 Object 7 Infrared heater 8 Heat insulating material 9 Heating case 10 Opening part 11 Support part 101 XY stage 201 Cooling fan 301 Heat insulating material 302 Heating 303 Copper plate

Claims (3)

A support for fixing the heating object;
A back surface heater for heating the back side of the observation surface of the heating object in contact or non-contact;
At least one axis moving stage on which the object to be heated, the support and the back surface heater are mounted and operated;
It has a uniform temperature region spread across the surface, and has an opening for observing the heating object in a part of the uniform temperature region, and observes the heating object by bringing it close to the heating object. It consists of a surface heater that heats from the surface side in a non-contact manner,
A heating apparatus characterized by operating the moving stage to simultaneously and uniformly heat the front and back surfaces of the heating object while observing or measuring the entire heating object through the opening. The heating apparatus according to claim 1, wherein at least one thermometer is installed for the heating object, and the temperature of the heating object is controlled by feedback control. The heating device according to claim 1 or 2, wherein a thin parallel plane transparent body that does not affect the optical system for observation or measurement is disposed in the opening.