JP4893939B2 - Heat treatment apparatus and heat treatment method for manufacturing object, and method for manufacturing piezoelectric device - Google Patents

Description

  The present invention relates to a heat treatment apparatus and heat treatment method for a manufacturing object, and a method for manufacturing a piezoelectric device.

  Manufacturing objects such as electronic devices are often manufactured through heat treatment. For example, an adhesive for fixing an electronic component in a package is heated, or an adhesive for bonding a lid to the package is heated. I do. Alternatively, for example, in the case of a piezoelectric vibrator in which a piezoelectric vibrating piece is bonded with an adhesive in the package, the gas generated from the adhesive adheres to the piezoelectric vibrating piece and has an adverse effect, so the package is sealed with a lid. Previously, the cured adhesive is heat treated to further heat the gas and exhaust the gas.

FIG. 8 is a partially enlarged view of a conventional heat treatment apparatus 1 for performing such heat treatment (see, for example, Patent Document 1).
That is, the electronic device 8 processed by the heat treatment apparatus 1 includes the base 2 serving as a package and the lead frame 4 electrically connected to an electronic component (not shown). The apparatus 1 is an apparatus that joins the base 2 and the lead frame 4 with low-melting glass (not shown).
Specifically, the electronic devices 8 are arranged in the horizontal direction on the heat block 5, and the electronic device 8 is heated from the heat block 5 by heat conduction. In addition, if the base 2 is warped only by the heat conduction type, the heat of the heat block 5 is not transmitted well, so the infrared lamp 6 also heats the electronic device 8.

Japanese Unexamined Patent Publication No. 63-179553

However, the heat treatment apparatus shown in FIG. 8 takes up space because of the need to arrange a plurality of electronic devices 8,... In a horizontal direction. It gets worse. For this reason, as shown in FIG. 9, a plurality of electronic devices 8,...
However, when the plurality of electronic devices 8,... Are stacked in the height direction and heated, the temperature is different between the upper side and the lower side in the chamber 7, so that variations in performance occur in each electronic device 8, In addition, the manufacturing time may be long.

  FIG. 10 is a temperature profile for explaining the occurrence of such variation in performance for each electronic device and the prolongation of the manufacturing time, and the electronic devices 8a, 8b, 8c having different vertical arrangements in the chamber. The temperature in the vicinity is being measured. As shown in this figure, it can be seen that as the temperature is increased, the temperature difference increases in accordance with the place where the electronic devices 8a, 8b, and 8c are placed. And if there is such a temperature difference, the performance of the product varies. Further, if it is attempted to maintain this increased temperature (at the time of keeping the temperature in FIG. 10), this varied temperature continues as it is. Furthermore, in the case of FIG. 10, if all the electronic devices 8a, 8b, and 8c are kept within 300 ° C. ± 10 ° C. which is within the allowable range of the set temperature, a considerable time is spent for temperature adjustment.

  The present invention is for solving the above-described problem, and a manufacturing object capable of preventing manufacturing variations and reducing manufacturing time even if the manufacturing objects are arranged in a height direction in a chamber. An object of the present invention is to provide a heat treatment apparatus, a heat treatment method, and a piezoelectric device manufacturing method.

According to the first aspect of the present invention, the chamber can accommodate a plurality of manufacturing objects arranged in the height direction, a gas supply means for filling the chamber with gas, and the inside of the chamber by radiant heat. A radiant heating means for heating; a stirring means for stirring the gas in the chamber when the radiant heating means is in operation; and a vacuum for exhausting the gas to evacuate the chamber. Heat treatment of an object to be manufactured, comprising: a generating means; a magazine that is housed in the chamber and has a shelf for placing the object to be manufactured; and a heat-conducting heating means for heating a placement portion on which the magazine is placed. Achieved by the device.

According to the configuration of the first invention, the chamber of the heat treatment apparatus has a plurality of production objects arranged in the height direction, so that a large number of production objects can be heat treated at a time.
Here, the heat treatment apparatus includes a gas supply means for filling a gas in the chamber, a radiant heating means for heating the inside of the chamber with radiant heat, and a gas in the chamber when the radiant heating means is operating. And stirring means for stirring. Therefore, the gas supplied by the gas supply means is heated by the radiant heating means, and the heated gas is stirred by the stirring means, so that the distribution of the heated gas in the chamber is made uniform and the temperature distribution is made uniform. It can be made uniform.
Furthermore, the heat treatment apparatus of the present invention has a vacuum generating means for discharging the gas and making the inside of the chamber in a vacuum state. For this reason, if the temperature distribution in the chamber is made uniform as described above and then the gas is exhausted to a vacuum state, this vacuum state serves as a heat insulating material, and the temperature in the chamber can be maintained. .
In this regard, even if the inside of the chamber is insulated in a vacuum state, the manufacturing object needs to be held in any part of the chamber, so heat escapes out of the chamber through the holding part. However, since the heating means of this apparatus is a radiant heating means, the manufacturing object can be efficiently heated even in a vacuum state. Therefore, if the heat that escapes from the chamber through the holding portion is heated by the radiant heating means, the temperature in the chamber can be maintained.
As described above, all or most of the objects to be manufactured arranged in the height direction can be easily heat-treated within the allowable range of the set temperature.
Thus, according to the present invention, it is possible to provide a manufacturing object heat treatment apparatus that can prevent manufacturing variations and reduce manufacturing time even if the manufacturing objects are arranged in the chamber in the height direction. it can.
Further, the chamber contains a magazine having a shelf for placing a product to be manufactured, and is provided with heat conduction heating means for heating the placing portion on which the magazine is placed. Therefore, heating by the radiant heating means can be assisted by the heat conduction heating means. Further, the heat conduction type heating means heats the magazine from the lower side through the mounting portion, and has a function of eliminating the temperature difference generated between the upper side and the lower side of the magazine. The effect of trying to make the temperature distribution in the chamber uniform with the stirring means can be assisted.

According to a second aspect of the invention, in the configuration of the first aspect of the invention , a thermocouple connected to a thin plate-like metal material in contact with the magazine is provided in the chamber.
According to the structure of 2nd invention , the thermocouple connected with the thin plate-shaped metal material which contacts a magazine is provided in the chamber. Therefore, the temperature close to the actual temperature of the magazine can be measured by the thermocouple through the thin plate-like metal material.

A third invention is characterized in that, in the configuration of the first or second invention , the surface of the magazine has a black color, and the inner surface of the chamber is a mirror surface.
According to the configuration of the third invention , the surface of the magazine has a black color, and the inner surface of the chamber is a mirror surface. Therefore, it is possible to heat the manufacturing object quickly by reflecting the radiation wave of the radiation type heating means within the chamber and improving the radiation absorption efficiency only for the magazine. And the inside of the chamber after a heating can be rapidly performed by narrowing down only the magazine to be heated.

According to a fourth aspect of the invention , in any one of the first to third aspects of the invention , the radiant heating means uses a halogen lamp that emits a radiant wave in the horizontal direction. It is characterized in that it is disposed on the lower side relative to at least the uppermost part of the plurality of manufacturing objects arranged in the height direction.
According to the configuration of the fourth aspect of the invention , the radiant heating means uses a halogen lamp that is irradiated with a radiant wave in the horizontal direction. The halogen lamp is applied to at least the uppermost part of the plurality of manufacturing objects. It is arranged relatively below. Therefore, since the radiant heating means does not directly heat at least the uppermost part of the manufacturing object, it is possible to prevent the temperature difference between the upper part and the lower part that is generated by the rise of heat from being widened.

According to a fifth aspect of the present invention, there is provided a heat treatment method for an electronic device comprising an adhesive or a brazing material as a component, wherein the plurality of electronic devices are arranged in a height direction in a chamber. Thereafter, a gas supply step for introducing gas, a first heating step for heating the inside of the chamber while stirring the gas, and generation of a vacuum for exhausting the gas to bring the inside of the chamber into a vacuum state A heat treatment of the electronic device , comprising: a step, and a second heating step of heating the electronic device in response to a temperature escaped from a contact region between the chamber that holds the electronic device and the chamber in the vacuum state Achieved by the method.

According to the structure of 5th invention , in the heat processing method of the electronic device which contains an adhesive agent or a brazing material in a component, a several electronic device can be arranged in a height direction in a chamber, and many electronic devices can be heat-processed at once. .
And since it has the gas supply process which puts in gas, and the 1st heating process which heated the inside of a chamber, stirring gas, even if heat is going to rise by the same operation as the 1st invention, The temperature distribution in the chamber can be made uniform by stirring the generated gas.
Thereafter, the heat treatment method includes a vacuum generation step for discharging the gas and making the inside of the chamber in a vacuum state, so that the temperature in the chamber can be maintained by the heat insulating material effect in the vacuum state.
Further, the heat treatment method includes a second heating step of heating the electronic device in response to the temperature escaped from the contact region between the member holding the electronic device and the chamber in a vacuum state. Therefore, even if heat escapes to the outside of the chamber through the contact area between the member holding the electronic device and the chamber in a vacuum state, the amount of the escaped heat can be heated to maintain the temperature in the chamber constant.
Thus, according to the present invention, it is possible to provide a heat treatment method for an electronic device that can prevent manufacturing variations and shorten the manufacturing time even if the electronic devices are arranged in the chamber in the height direction.

According to the sixth aspect of the present invention , the mount for mounting the piezoelectric vibrating piece on the adhesive in the package and heating the adhesive to join the package and the piezoelectric vibrating piece is provided. A method of manufacturing a piezoelectric device, comprising: a step, an annealing step for further heating the adhesive, and a lid sealing step for joining the package and the lid by heating a brazing material, wherein the heating is performed In any of the steps, after arranging a plurality of unfinished piezoelectric devices in the height direction in the chamber, a gas supply step of putting gas into the chamber, and heating the chamber while stirring the gas A first heating step, a vacuum generating step of exhausting the gas and making the inside of the chamber in a vacuum state, and a contact region between the member holding the piezoelectric device and the chamber in the vacuum state. In response to relief temperature is achieved by the method for manufacturing a piezoelectric device and a second heating step of heating the piezoelectric device.

According to the configuration of the sixth aspect of the invention , the piezoelectric device manufacturing method arranges a plurality of unfinished piezoelectric devices in the height direction in the chamber in any of the steps of applying heat. Can be heat treated. And since it has the 1st heating process which heated the inside of a chamber, stirring the gas, the gas supply process which puts in gas, and by the action similar to the 1st invention, by the stirring of the heated gas The temperature distribution in the chamber can be made uniform. In addition, since the method includes a vacuum generation step for discharging the gas and making the inside of the chamber in a vacuum state, the temperature in the chamber can be maintained by the heat insulating material effect in the vacuum state. And in a vacuum state, it has the 2nd heating process which heats a piezoelectric device corresponding to the temperature which escaped from the contact area of the member holding a piezoelectric device, and a chamber. Therefore, even if heat escapes to the outside of the chamber through the contact region between the member holding the piezoelectric device and the chamber in a vacuum state, the temperature inside the chamber can be maintained constant by heating the heat.
Thus, according to the present invention, it is possible to provide a method for manufacturing a piezoelectric device that can prevent manufacturing variations and reduce manufacturing time even if the manufacturing objects are arranged in the chamber in the height direction. .

According to a seventh invention, in the configuration of the sixth invention , the mounting step and the annealing step are continuously performed in the same chamber, and the mounting step includes the gas supply step and the gas supply step. A first heating step, and the annealing step includes the vacuum generation step and the second heating step.
According to the configuration of the seventh invention , since the mounting process includes the gas supply process and the first heating process, the same effect as the seventh invention is exhibited, and the temperature distribution in the chamber is made uniform. Thus, it is possible to join piezoelectric vibrating pieces without variation.
In addition, since the annealing process has a vacuum generation process and a second heating process, the same effect as the sixth invention is exhibited, and the gas generated from the adhesive is maintained while keeping the temperature in the chamber constant. Can be issued. Since this annealing step is performed in a vacuum state, the gas generated from the adhesive can be efficiently exhausted.
Furthermore, since the mounting process and the annealing process are continuously performed in the same chamber, rapid manufacturing is possible.

FIG. 1 is a schematic longitudinal sectional view of a piezoelectric device 10 as an example of a manufacturing object to be processed using a heat treatment apparatus according to an embodiment of the present invention.
The piezoelectric device 10 in FIG. 1 illustrates a piezoelectric vibrator, and a piezoelectric vibrating piece 14 is accommodated in a package 12.
The package 12 is formed, for example, by laminating and sintering a plurality of ceramic bases, and has a rectangular or box shape as a whole. The package 12 is provided with an internal space S having an opening 16 opened at the top by making the vicinity of the center concave. The internal space S is a space that accommodates the piezoelectric vibrating piece 14 formed of, for example, crystal.

On the inner bottom surface exposed to the internal space S of the package 12, an electrode portion 20 made of gold, silver or the like for applying a driving voltage to the piezoelectric vibrating piece 14 is provided, and an adhesive 22 is provided on the electrode portion 20. Is applied. The piezoelectric vibrating piece 14 is placed on the adhesive 22, and the adhesive 22 is heated and cured, so that the package 12 and the piezoelectric vibrating piece 14 are joined.
In the case of the present embodiment, the adhesive 22 is, for example, an epoxy, silicone, polyimide, or other thermosetting resin adhesive, or a conductive adhesive such as a so-called silver paste in which silver is added as a conductive filler. Is used.

  Then, the lid 13 is joined to the end surface of the package 12 on the opening 16 side using the brazing material 18, thereby sealing the internal space S. Even after the lid is sealed, the lid 13 transmits light so that the metal coating portion (not shown) of the piezoelectric vibrating piece 14 is irradiated with the laser light L and the frequency can be adjusted by the mass reduction method. It is formed from a glass material. As the brazing material 18, low melting point glass, seam ring, or the like can be used. However, in the case of the present embodiment, the lid 13 is made of a glass material as described above, and thus low melting point glass is used.

FIG. 2 shows a simple manufacturing process of the piezoelectric device 10 of FIG. In the following description, reference is made to FIG. 1 for signs not shown in FIG.
That is, in the above-described piezoelectric device 10, the adhesive 22 is applied to the pre-formed package 12, the piezoelectric vibrating piece 14 is placed thereon, the adhesive 22 is heated, and the package 12 and the piezoelectric vibrating piece are heated. 14 (S1: mounting step in FIG. 2).
Next, in a state where the piezoelectric vibrating piece 14 is bonded, the adhesive 22 is further heated (S2 in FIG. 2: annealing step). It is preferable to set a long time so that the gas component contained in the adhesive 22 is sufficiently discharged to the outside. In this embodiment, about 2 of the silicone-based conductive adhesive is used. Heating over time. Thereby, generation | occurrence | production of the gas in subsequent heat processing can be prevented.
Subsequently, the package 12 and the lid 13 are joined by heating the brazing material 18 (S3 in FIG. 2: lid sealing step), and then the laser beam L is transmitted through the transparent lid 13 and the piezoelectric vibrating piece 14. Then, the frequency is finely adjusted by the mass reduction method (ST4 in FIG. 2: frequency adjustment), and the piezoelectric device 10 is completed.

3 to 5 show a heat treatment apparatus 30 according to an embodiment of the present invention, which is an apparatus for performing heat treatment in the manufacturing process of the piezoelectric device described above. 3 is a block diagram showing the overall configuration of the heat treatment apparatus 30, FIG. 4 is a schematic perspective view of a chamber portion of the heat treatment apparatus 30, and FIG. 5 is a schematic perspective view of a magazine accommodated in the chamber.
As shown in these drawings, the heat treatment apparatus 30 includes a chamber 40 and a magazine 50 accommodated in the chamber 40.

As shown in FIG. 3, the chamber 40 has an accommodation space S1 in which a plurality of piezoelectric devices (not shown), which are examples of manufacturing objects, are arranged in the height direction, and this accommodation space S1. Can be sealed by a door (not shown). In the case of this embodiment, a plurality of piezoelectric devices are placed in the magazine 50, and the magazine 50 is accommodated in the chamber 40, whereby the plurality of piezoelectric devices are arranged in the height direction.
The chamber 40 accommodates two magazines 50 (two frames surrounded by a one-dot chain line in FIG. 4 are the place to place them), but the present invention is not limited to this. Three or more magazines 50 may be accommodated. Further, the present invention does not necessarily use the magazine 50. For example, a shelf may be provided directly in the chamber 40 and a piezoelectric device may be placed on the shelf.

As shown in FIGS. 3 and 4, the chamber 40 is provided with a radiant heating means 60 for heating a plurality of piezoelectric devices arranged in the height direction.
The radiant heating means 60 is capable of heating the piezoelectric device without contacting the piezoelectric device and without passing through a substance by releasing thermal energy as an electromagnetic wave, and uses an infrared lamp or the like. Can do.
The radiant heating means 60 of the present embodiment includes, for example, a plurality of line-shaped elements that include a tungsten filament in a tubular bulb that is long in one direction, encloses a halogen gas therein, and emits infrared rays having a predetermined wavelength. .., A reflector 64 as a reflecting surface disposed on each halogen lamp 62, and a drive unit (not shown) for each halogen lamp 62 are used.

The halogen lamps 62 are arranged in a line in the horizontal direction on each of the inner surfaces 40a, 40b of the chamber 40 facing both side surfaces of the magazine 50 irradiated with radiation waves, and a plurality of halogen lamps 62, 62,. -Are arranged in the height direction so as to be parallel to each other.
The reflector 64 is a reflecting means having a concave mirror surface, and is disposed on the side opposite to the object to be irradiated with the radiation wave of each halogen lamp 62. The reflectors 64 are continuously or integrally joined so that the reflectors 64 are in contact with each other and are arranged in the height direction, and each reflector 64 reflects the radiation wave emitted from each halogen lamp 62. Each radiant wave is substantially parallel from the front and is set to irradiate horizontally.
In this way, the radiant heating means 60 can uniformly irradiate the region to be irradiated of the magazine 50 without unevenness.

  Further, as shown in FIG. 3, the halogen lamp 62 is disposed on the lower side relative to at least the uppermost portion 51 of a plurality of piezoelectric devices (not shown) arranged in the height direction in the magazine 50. Has been. For this reason, when the radiant heating means 60 is driven, the radiant wave is not directly applied to at least the side surface of the magazine 50 near the top of the piezoelectric device. Therefore, it is possible to prevent the temperature difference between the upper part and the lower part that is generated by the rise of heat from being widened.

  Note that the inner surface of the chamber 40 is a mirror surface formed of, for example, SUS or aluminum so that the radiation wave of the radiant heating means 60 is reflected. Thereby, for example, when the radiant heating means 60 is driven in a vacuum state to be described later, the radiant wave can be reflected by the inner surface of the chamber 40 and the radiant wave can be absorbed only by the magazine 50. In the case of this embodiment, an aluminum mirror surface having a high reflectance of 70 to 80% is used for the inner surface of the chamber 40.

Further, as shown in FIG. 3, the radiant heating means 60 is preferably connected to a constant current control device 66. The constant current control device 66 applies a drive current to the radiant heating means 60 stably with a constant voltage, thereby controlling the amount of heat so as not to occur, and is necessary for starting up the radiant heating means 60. Equipped with various control and disconnection detection functions.
The constant current control device 66 is connected to control means 28 for controlling the entire heat treatment apparatus 30. The control means 28 switches the amount of heat of the radiant heating means 60 via the constant current control device 66. Give instructions to set working hours.

A pipe 71 that opens into the chamber 40 is drawn out to the outside, and the pipe 71 is connected to a gas supply means 76 such as a gas cylinder. The chamber 40 is provided with a stirring means 70 for stirring the gas in the chamber 40.
These gas supply means 76 and stirring means 70 are means for making the temperature distribution in the chamber 40 uniform.

That is, the gas supply means 76 fills the chamber 40 with gas, and this gas is heated by the radiant heating means 60 described above.
Note that an inert gas is preferably used as the gas supplied from the gas supply means 50 in order to prevent the occurrence of deterioration and damage. In the present embodiment, nitrogen having high thermal conductivity is used in the chamber 40. Is in a nitrogen atmosphere.
When the gas is heated by the radiant heating means 60, the heated gas rises. At this time, as described above, the chamber 40 is provided with the stirring means 70, and the stirring means 70 is provided on the upper surface (ie, ceiling) 40 d of the chamber 40 and filled in the chamber 40, for example. It consists of a rotating fan or the like as means for convection of gas in the vertical direction. For this reason, when the stirring means 70 is operated, the heated gas convects in the vertical direction, whereby the heated gas is uniformly distributed in the chamber 40 and the temperature distribution can be made uniform.

  The gas supply means 50 and the stirring means 70 are connected to the control means 28. The control means 28 instructs the gas supply means 50 about the supply amount and supply time of the inert gas, and the like. The timing of driving the stirring means 70 is managed.

Further, a conduit 72 that opens into the chamber 40 is drawn out to the outside, and this conduit 72 is connected to a vacuum generating means 74 such as a vacuum pump.
The vacuum generating means 74 is a means for making the inside of the chamber 40 in a vacuum state. In the case of this embodiment, the vacuum generating means 74 is roughly evacuated when the gas supply means 50 makes the inside of the chamber 40 a nitrogen atmosphere. Further, the vacuum generating means 74 is used for maintaining a set temperature in the chamber 40. In other words, the vacuum generating means 74 evacuates the chamber 40 when the temperature around the piezoelectric device is kept constant after the chamber 40 reaches a predetermined set temperature. Thereby, the vacuum state exhibits an excellent heat insulating effect, and the temperature in the chamber 40 can be kept constant without applying heat unless there is a path for heat to escape.
The vacuum state here may be low or high depending on the desired heat insulation effect, but is preferably a high vacuum state. In the present embodiment, the vacuum generating means 74 is: The chamber 40 is evacuated so that the pressure is reduced to about 10 ⁻⁵ Pa.

The magazine 50 is a member that holds a piezoelectric device that is a manufacturing object, and is detachably accommodated in the chamber 40. In the case of this embodiment, the magazine 50 is inserted in the depth direction of the chamber 40 along the guides 47 shown in FIG. 4, and as shown in FIGS. 50c and two opposite side surfaces 50a and 50b which are vertically raised from two opposite sides of the bottom 50c, and the side surfaces are two side surfaces facing the radiation heating means 60 and 60. Only 50a and 50b are provided.
And inside the magazine 50, it has several shelf steps 52,52, ... so that the piezoelectric device which is several manufacture objects may be arranged in a height direction.
Specifically, the shelf 52 is formed on the inner side (that is, the inner side surface) of the side surface portions 50a and 50b irradiated with the radiation wave of the magazine 50, and is supported by a plurality of projecting portions 54 and 54 protruding inward. Yes. The shelf 52 is in the form of a tray that can be attached to and detached from the magazine 50. As shown in FIG. 5, the shelf 52 holds a plurality of piezoelectric devices with recesses 56 that match the outer shape of the piezoelectric device. .

The magazine 50 is placed on a placement portion 42 disposed on the inner bottom 40 c of the chamber 40, and the placement portion 42 is heated by heat conduction heating means 44.
As shown in FIG. 3, the heat conduction type heating means 44 includes a sheath heater built in the mounting portion 42, and assists the heating by the radiant type heating means 60 described above. More specifically, the heat conduction type heating means 44 heats the magazine 50 from the lower side through the mounting portion 42 arranged under the magazine 50, and is generated on the upper side and the lower side of the magazine 50. The temperature difference that was made is eliminated.

  Further, the mounting portion 42 of the present embodiment is cooled by the cooling means 46. The cooling means 46 is formed by, for example, a cooling pipe 49 built in the mounting portion 42 and a pump 43 that supplies cooling water to the cooling pipe 49. Thereby, after finishing a predetermined manufacturing process, the magazine 50 is cooled. The cooling means 46 and the heat conduction type heating means 44 are connected to the control means 28 and are controlled in accordance with the temperature of the magazine 50.

  As shown in FIGS. 3 and 4, openings 71 a and 72 a of pipe lines 71 and 72 connected to the gas supply means 50 and the vacuum generation means 74 are provided on the mounting portion 42 where the magazine 50 is placed. For this reason, as shown in FIGS. 3 and 5, the bottom 50c of the magazine 50 is formed with a through hole 56 so as not to block the openings 71a and 72a. The through-hole 56 reduces the contact area between the magazine 50 and the mounting portion 42 so that the heat of the magazine 50 is difficult to escape to the outside through the mounting portion 42.

  Further, the surface of the magazine 50 is made of a black color, so that the radiation absorption efficiency of the radiant heating means 60 can be enhanced. Therefore, the absorption efficiency of the radiation wave can be increased only for the magazine 50, and the manufacturing object can be quickly heated.

Further, when the magazine 50 is accommodated in the chamber 40, the magazine 50 comes into contact with a thin metal material 39 connected to a thermocouple 48 provided in the chamber 40 in order to measure the temperature.
Specifically, as shown in FIGS. 3 and 4, the thermocouple 48 is a metal material composed of a leaf spring that bends in a direction perpendicular to the direction in which the magazine 50 is inserted into the chamber 40 (excluding the vertical direction). 39 and welded. As a result, when the magazine 50 is inserted along the guide 47, the metal material 39 made of a leaf spring surely comes into contact with both side surfaces 50 a and 50 b irradiated with the radiant wave of the magazine 50, The temperature of the magazine 50 can be measured by the pair 48. The thermocouple 48 is connected to the control means 28, and the control means 28 radiates the heating means 60, the heat conduction type heating means 44, the cooling means 46, and the stirrer according to the temperature measured by the thermocouple 48. The means 70 and the like are controlled.

The heat treatment apparatus 30 according to the present embodiment is configured as described above. Hereinafter, the operation and the like will be described with reference to FIGS. 1 to 5 as appropriate, mainly with reference to FIGS.
FIG. 6 is a flowchart of a method for heat-treating a piezoelectric device using the heat treatment apparatus described above, and is a flow used in the piezoelectric device mounting process (ST1 in FIG. 2) and the annealing process (ST2 in FIG. 2). . FIG. 7 is a temperature profile of the heat treatment of FIG. 6, and the temperature is measured for each of the plurality of shelves of the magazine.

  That is, as described above, in the piezoelectric device mounting step (ST1 in FIG. 2), an adhesive is applied to the inner bottom of the package formed in advance, and the piezoelectric vibrating piece is placed on the adhesive. A plurality of objects to be heated (piezoelectric devices before completion) in such a state are formed, and these are placed on the shelf of the magazine 50 shown in FIG. After housing and sealing the chamber 40, heat treatment starts (ST10 in FIG. 6).

First, the inside of the chamber 40 is roughly evacuated through the pipe 72 by the vacuum generating means 74 such as a vacuum pump shown in FIG. 3 to make the inside of the chamber 40 a vacuum atmosphere to some extent (ST11 in FIG. 6). The rough evacuation is not always necessary, but is preferably performed in view of introducing an inert gas into the chamber 40 in order to prevent later-described deterioration and corrosion resistance.
Next, when the inside of the chamber 40 shown in FIG. 3 reaches a predetermined degree of vacuum, the gas supply means 76 is operated by opening an electromagnetic valve connected to a gas cylinder or the like based on an instruction from the control means 28, and the like. An active gas, preferably nitrogen that is easily heated, is supplied into the chamber 40 to form a nitrogen atmosphere (ST12 in FIG. 6: gas supply step).

Next, the radiation type heating means 60 and the stirring means 70 shown in FIG. 3 are operated (ST13 in FIG. 6: first heating step). Specifically, after the inside of the chamber is in a nitrogen atmosphere, based on an instruction from the control means 28 shown in FIG. 3, the radiant heating means 60 composed of a halogen lamp or the like is left for a predetermined time (30 minutes in this embodiment). Before and after operation, the nitrogen gas is heated. And when this radiation type heating means 60 is operated, the stirring means 70 which consists of a fan etc. which are shown in FIG. 3 is also operated.
Thereby, the heated nitrogen gas convects in the vertical direction, and the temperature distribution (gas distribution) in the chamber 40 can be made uniform. In the case of this embodiment, as shown in FIG. 7, the temperature of each shelf of the magazine at the time of temperature increase is almost the same, about 263 ° C. at the lowest temperature shelf and about 280 ° C. at the highest temperature shelf. . Therefore, even if a plurality of piezoelectric devices are accommodated side by side in the height direction in the chamber, manufacturing variations can be eliminated. In addition, since most piezoelectric devices except for special circumstances are within the allowable range of the set temperature, it is not necessary to perform the temperature adjustment work within the allowable range of the set temperature as in the past. Become.

Then, the conductive adhesive 22 applied to the package 12 shown in FIG. 1 is cured by heating at around 275 ° C., and the piezoelectric vibrating piece 14 and the package 12 can be joined.
In the case of the present embodiment, as shown in FIG. 7, the temperature in the chamber can be raised rapidly as shown in FIG. 7, and the temperature difference between the upper side and the lower side of the magazine does not occur. The heat conduction heating means 44 such as a sheath heater under the magazine 50 is also operated.

Next, the temperature of the side portions 50a and 50b of the magazine 50 is measured by the thermocouple 48 shown in FIG. 3 and when the target temperature is reached, the vacuum generating means 74 is operated and the vacuum in the chamber is connected via the pipe line 72. (ST14 in FIG. 6: vacuum generation step).
Specifically, after the first heating step of ST13 in FIG. 6 is completed, the piezoelectric vibrating piece and the package joined with the conductive adhesive enter the chamber without opening the chamber door. The chamber 40 is evacuated to a pressure of about 10 ⁻⁵ Pa.

Then, since the vacuum exhibits an excellent heat insulating effect, basically, the temperature of the magazine around 275 ° C. is maintained without being heated by the heating means. However, as shown in FIG. 3, the bottom portion 50 c of the magazine 50 is in contact with the placement portion 42, so that the heat of the magazine 50 escapes to the outside through the placement portion 42. For this reason, the radiation type heating means 60 and / or the heat conduction type heating means 44 are driven by the amount of heat escaped from the contact portion between the magazine 50 and the mounting portion 42 (ST15 in FIG. 6: second). Heating step).
Specifically, since the thermocouple 48 measures the temperature of the magazine 50, the heat that has escaped through the mounting portion 42 of the magazine 50 can be measured by this thermocouple 48, and the measured information is The control means 28 determines and the control means 28 gives an instruction to turn on and off the switch of the radiation type heating means 60 and / or the heat conduction type heating means 44 and adjust the power as appropriate. As a result, as shown in FIG. 7, substantially the same setpoint temperature can be maintained regardless of the difference in the number of magazine shelves.

In the case of the present embodiment, as shown in FIG. 7, the vacuum generation step and the second heating step (ST14, 15 in FIG. 6) are performed for about 2 hours while maintaining the temperature around 275 ° C. Gas is actively emitted from the adhesive for joining the resonator element and the package (ST2 in FIG. 2: annealing process). Therefore, it is possible to suppress the generation of gas during the lid sealing step (ST3 in FIG. 2) to be performed thereafter and heat treatment such as reflow at the customer site.
Furthermore, according to the present invention, the chamber 40 is evacuated by the vacuum generating means 74 shown in FIG. 3 during the time period for maintaining this temperature, so that the gas generated from the adhesive can be exhausted.

Next, after reaching the set time for maintaining the temperature by the timer, a cooling process for cooling the inside of the chamber is performed (ST16 in FIG. 6).
Specifically, the driving of the radiation type heating means 60 and the heat conduction type heating means 44 shown in FIG. 3 is stopped, and the gas supply means 76 shown in FIG. 3 used in ST12 of FIG. Then, the cooling means 46 is operated, and cooling water is supplied to a cooling pipe 49 built in the mounting portion 42 to cool the water. In the present embodiment, the entire chamber is not heated in ST14 and 15 in FIG. 6 (that is, ST2 in FIG. 2: annealing process), but only the magazine 50 including the piezoelectric device is heated. Can be performed more quickly.
Next, when the temperature at which the magazine 50 shown in FIG. 3 can be taken out is reached, the magazine 50 is taken out from the chamber 40 (ST17 in FIG. 6), and the annealing process of ST2 in FIG.

The present invention is not limited to the above-described embodiment. Each configuration of each embodiment and each modification may be combined or omitted as appropriate, or may be combined with other configurations not shown.
For example, the manufacturing object used in the heat treatment apparatus of the present invention is not limited to the above-described piezoelectric device, and may be a piezoelectric oscillator, a piezoelectric surface acoustic wave device, a piezoelectric gyro sensor, or the like. As long as it is accompanied, an electronic device other than the piezoelectric device may be used.

The schematic longitudinal cross-sectional view of a piezoelectric device as an illustration of the manufacturing object processed using the heat processing apparatus which concerns on embodiment of this invention. A simple manufacturing process of the piezoelectric device of FIG. The block diagram which shows the whole structure of the heat processing apparatus which concerns on embodiment of this invention. The schematic perspective view of the chamber part of the heat processing apparatus which concerns on embodiment of this invention. The schematic perspective view of the magazine accommodated in a chamber. The flowchart of the method of heat-processing a piezoelectric device using the heat processing apparatus which concerns on embodiment of this invention. The temperature profile of the heat processing of FIG. The elements on larger scale of the conventional heat processing apparatus. The conceptual diagram which piled up the several electronic device in the height direction in the chamber. A temperature profile to explain the occurrence of performance variations for each electronic device and the prolongation of manufacturing time.

Explanation of symbols

  30 ... heat treatment equipment, 40 ... chamber, 42 ... mounting means, 44 ... heat conduction heating means, 50 ... magazine, 60 ... radiation heating means, 62 ... Halogen lamp, 70 ... stirring means, 74 ... vacuum generating means, 76 ... gas supply means

Claims (7)

A chamber that can accommodate a plurality of manufacturing objects arranged in the height direction;
Gas supply means for filling the chamber with gas;
Radiant heating means for heating the chamber with radiant heat;
Stirring means for stirring the gas in the chamber when the radiant heating means is in operation;
A vacuum generating means for discharging the gas and bringing the chamber into a vacuum state;
A magazine housed in the chamber and having a shelf to place the manufacturing object;
A heat treatment apparatus for an object to be manufactured, comprising: a heat-conducting heating means for heating a placement portion on which the magazine is placed . The heat treatment apparatus for a manufacturing object according to claim 1 , wherein a thermocouple connected to a thin plate-shaped metal material that contacts the magazine is provided in the chamber. The heat treatment apparatus for a manufacturing object according to claim 1 or 2 , wherein the surface of the magazine has a black color, and the inner surface of the chamber is a mirror surface. The radiant heating means uses a halogen lamp that is irradiated with a radiant wave in the horizontal direction, and the halogen lamp is relative to at least the uppermost part of the plurality of manufacturing objects arranged in the height direction. The heat treatment apparatus for a manufacturing object according to any one of claims 1 to 3 , wherein the heat treatment apparatus is disposed on the lower side. A heat treatment method for an electronic device including an adhesive or brazing material in a component,
A gas supply step of putting gas after arranging the plurality of electronic devices in the chamber in the height direction,
A first heating step in which the inside of the chamber is heated while stirring the gas;
A vacuum generating step of exhausting the gas and bringing the chamber into a vacuum state;
In the vacuum state, the electronic device in response to the temperature fled from the contact area between the member and the chamber for holding the electronic device, characterized by comprising a second heating step for heating the electronic device Heat treatment method. Mounting a piezoelectric vibrating piece on an adhesive in a package, heating the adhesive to join the package and the piezoelectric vibrating piece, an annealing step for further heating the adhesive, and A method for manufacturing a piezoelectric device, comprising: a lid sealing step for joining a package and a lid by heating a brazing material,
In any step of performing the heat treatment,
A gas supply step of putting a gas into the chamber after arranging a plurality of piezoelectric devices before completion in the height direction in the chamber;
A first heating step of heating the inside of the chamber while stirring the gas;
A vacuum generating step of exhausting the gas and bringing the chamber into a vacuum state;
A second heating step of heating the piezoelectric device in response to a temperature escaped from a contact area between the member holding the piezoelectric device and the chamber in the vacuum state. Production method. The mounting step and the annealing step are performed continuously in the same chamber,
The mounting step includes the gas supply step and the first heating step,
The method for manufacturing a piezoelectric device according to claim 6 , wherein the annealing step includes the vacuum generation step and the second heating step.

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