JP3483239B2 - Heater structure of vacuum oven chamber - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heater structure of a vacuum oven chamber for heating and drying a package mounted on a carrier and containing a chip therein in a vacuum. Things. 2. Description of the Related Art In general, as a package for accommodating a chip, a ceramic package in which a metal seal frame is bonded to a ceramic substrate, a metal package entirely formed of metal, and the like are used. There are a number of these packages in which a chip is housed and the internal wiring with the leads is positioned on a carrier. As described above, a package mounted on a carrier is first carried into a vacuum oven chamber and dried by heating. Next, after a cap is placed on the open end of the package, the cap is temporarily fixed to the package by spot welding. The joint between the package and the cap temporarily fixed by spot welding is pressed and energized by a pair of roller electrodes rotating along the opposing peripheral edges of the cap, and the package opening end is generated by Joule heat generated at the joint. The part and the cap are seam-welded. [0004] In the case where the package and the cap are seam-welded in this manner, in a process prior to the seam welding process, the carrier on which the package is mounted is loaded into the vacuum oven chamber as described above, and is maintained for a predetermined time. It must be dried by heating in a vacuum. As described above, in order to heat and dry the package, a conventional vacuum oven chamber has a heater 1 inside as shown in FIGS.
1 is provided, and a shelf 13a made of a number of members having good thermal conductivity (for example, nickel-plated copper plate) supported by the heat block 12 is provided on the shelf 13a. Place the tray 3,
The carrier 5 on which a large number of packages 4 are mounted is placed in the tray 3, and the shelf 13 a is heated by the heat from the heater 11 to heat and dry the packages. [0005] With such a configuration, the heat from the heater block 12 can uniformly heat the shelf plate 13a, and a flat temperature distribution can be obtained. At the time of this heating, the vacuum oven chamber is filled with nitrogen gas to generate convective heat therein, thereby shortening the heating time of the shelf board. However, when heating in nitrogen gas,
Similar to the case where the heating temperature of each package 4 varies, there is a problem that the characteristics of the chips housed in the package 4 change, the yield rate decreases, and the yield decreases. SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and provides a heater structure of a vacuum oven chamber capable of improving the emissivity of a shelf board and shortening a heating time without generating convection heat. The purpose is to: [0007] The heater structure of the vacuum oven chamber of the present invention is mounted on a carrier and is used in a process prior to a welding process for welding a cap to a package containing a chip therein. A vacuum oven chamber for carrying the carrier into the chamber and heating and drying the package in a vacuum, wherein the shelf supports a shelf plate formed of a member having good thermal conductivity; A body is placed in the vacuum oven chamber, and the carrier on which the package is mounted is placed on the shelf plate of the shelf heated by conduction heat from a separately provided heater, and the package is placed. In a vacuum oven chamber to be heated and dried, a titanium aluminum nitride film is formed on the surface of the shelf. It is characterized by the following. FIG. 1 is a block diagram showing an embodiment of the present invention; FIG.
This will be described in detail based on FIG. FIG. 1 is a front view showing an embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. 3 is an enlarged explanatory view of a main part. The same components as those in the conventional example have the same names and are given the same numbers, and the description thereof is omitted. In FIGS. 1 to 3, reference numeral 10 denotes a shelf disposed in a vacuum oven chamber 23, a heater block 12 having heaters 11 embedded on both sides, and a shelf plate 13 supported by the heater block 12. It consists of: The heater block 12 includes an arbitrary number of heaters 1.
1 is buried as a heating source, and a plurality of shelves 13 made of a metal member such as copper having good thermal conductivity are supported with a gap therebetween. A film of titanium aluminum nitride is formed on the lower surface of the shelf 13 (the lower surface in the figure). In this embodiment, about three heaters 11 were used on one side. It should be noted that since the shelf plate 13 having a large thickness has a large heat capacity, the temperature distribution is uniform, which is preferable. On the upper surface of the shelf 13, a stainless steel auxiliary shelf 14 whose bottom is formed in a dish shape having the same shape as the shelf 13 is fixed to the shelf 13 with screws 15. The auxiliary shelves 14 are for preventing the shelves 13 from being cut when the shelves 13 are formed of a soft member having a high thermal conductivity such as copper. Is not necessarily required when the member is formed of a member having high hardness. Further, since the surface of the auxiliary shelf plate 14 is formed smoothly, it also serves as a guide when the tray 3 is taken in and out. In addition, the shelf 13 is the auxiliary shelf 1
It is necessary to have a larger heat capacity than 4 and tray 3. Reference numerals 16 and 17 denote solenoid valves for injecting and exhausting nitrogen gas, respectively, which are controlled by a control unit 22 to be opened and closed when nitrogen gas is injected and exhausted, respectively. 18,
19 is an input end and an output end of the heating current to the heater 11,
A cooling pipe 20 circulates cooling water in this embodiment. 21 is an air exhaust valve, 22 is a control unit, controls the heating temperature and heating time of the shelf 13, injects nitrogen gas into the vacuum oven chamber 23, controls exhaust, controls the temperature of cooling water, and exhausts air. Each part of the vacuum oven chamber 23 is controlled, such as control of an exhaust valve 21 for the purpose. Reference numeral 24 denotes a support column. The vacuum oven chamber 23 is fixed to a main body (not shown), and is also fixed to the control unit 22 by the support column 24. Reference numeral 25 denotes a front door of the vacuum oven chamber 23. With this configuration, first, the tray 3 on which the package 4 is mounted is placed on each stage of the shelf composed of the shelf 13 and the auxiliary shelf 14, and then the exhaust valve 21 is turned on. The air inside the vacuum oven chamber 23 is exhausted, and the inside is evacuated. Next, in response to a command from the control unit 22, a heating current is supplied to the heater 11, the heater 11 is heated, and the heater block 12 is heated as a whole.
It serves as a heating source for the shelf 13. Since each shelf 13 is formed of a member having good thermal conductivity, the shelf 13 is heated uniformly by the conduction heat from the heater block 12 integrally with each shelf 13 and the auxiliary shelf 14 thereof. A temperature distribution is obtained. At this time, since the titanium aluminum nitride film is formed on the lower surface of each shelf 13, radiant heat is also generated in the vacuum oven chamber 23, and the heating time of the shelf 13 can be reduced. In this state, the package 4 mounted on the carrier 5 on the tray 3 is heated and dried at a predetermined temperature for a predetermined time. After a lapse of a predetermined time, the electromagnetic valve 16 for injecting nitrogen gas is instructed by a command from the control unit 22 to open the front door 25 of the vacuum oven chamber 23.
Operates to inject nitrogen gas into the vacuum oven chamber 23. When a sufficient amount of nitrogen gas is injected, the electromagnetic valve 16 is closed, the front door 25 of the vacuum oven chamber 23 is opened and the tray 3 is carried out from the inside by the command from the control unit 22, and the process proceeds to the next temporary fixing step. Conveyed. According to the present invention, as described above, the carrier is mounted in a chamber in a process prior to a welding process for welding a cap to a package mounted on a carrier and containing a chip therein. In a vacuum oven chamber for heating and drying the package in a vacuum, a shelf plate formed of a member having a good thermal conductivity with a titanium aluminum nitride film having a high emissivity formed on a surface thereof is supported. And the carrier having the package mounted on the shelf plate of the shelf heated by conduction heat from a separately provided heater while disposing the shelf in the vacuum oven chamber. Since the package is placed and heated and dried, there is no need to fill the inside with nitrogen gas to shorten the heating time. Therefore, the characteristics of the chip housed in the package do not change, the non-defective rate is improved,
Yield improves. Therefore, according to the present invention, it is possible to provide a highly reliable heater structure of a vacuum oven chamber capable of shortening the heating time.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view showing an embodiment of the present invention. FIG. 2 shows an embodiment of the present invention and is a plan view of FIG. FIG. 3 shows an embodiment of the present invention and is an enlarged explanatory view of a main part. FIG. 4 is an explanatory diagram showing a conventional example. FIG. 5 is an explanatory diagram showing a state of a package 4 carried into a vacuum oven chamber. [Description of Signs] 3 tray 4 package 5 carrier 10 shelf 11 heater 12 heater block 13 shelf 14 auxiliary shelf 23 vacuum oven chamber

Claims (1)

(57) [Claim 1] The carrier is loaded into a chamber in a process preceding a welding process for welding a cap to a package mounted on the carrier and containing a chip therein. A vacuum oven chamber for heating and drying the package in a vacuum, wherein the shelf supports a shelf formed of a member having good thermal conductivity, and the shelf is disposed in the vacuum oven chamber. And a vacuum oven chamber in which the carrier on which the package is mounted is placed on the shelf of the shelf heated by conduction heat from a separately provided heater and the package is heated and dried. 3. The heater structure of a vacuum oven chamber according to claim 1, wherein a titanium aluminum nitride film is formed on a surface of the shelf.