JP2003282608A - Contact heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a ceramic heater employed for a conventional contact heating device raises the temperature of an electrode extraction connection when the heater is used repeatedly at high temperatures to cause a stress in a brazed part upon operating the contact heating device by the difference of a thermal expansion coefficient between the ceramic heater, small in a thermal expansion, and an electrode fitting of large thermal expansion, whereby crack is readily generated in the periphery of the brazed part and the life of the heater is shortened. <P>SOLUTION: The ceramic heater is constituted of a heat generating part a with built-in heat generating resistor, a lead part substantially vertical to the main surface of the ceramic heater connected to the heat generating resistor, and a recessed part surrounded by the heat generating part and the lead part. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact heating device such as a die bonding heater used when a semiconductor bare chip is mounted on a substrate to contact an object to be heated.

[0002]

2. Description of the Related Art As a method of mounting a semiconductor bare chip on a substrate, an ACF (ACF: anisotropic condu) using a resin adhesive such as an anisotropic conductive film is used.
The active film (cive film) connection method or the flip-chip connection method using a low melting point brazing material such as Au-Si or Au-Sn used in a multi-chip module is used.

For example, in the flip chip connection method, a semiconductor chip is placed on a multi-layer package substrate, and the upper surface of the semiconductor chip is heated by a contact heating device having a built-in ceramic heater and pressed to perform bonding. At this time, the wiring can be performed while the solder bumps provided for the both are used for bonding.

Such a contact heating device is shown in FIGS.
As shown in (a) and (b), a ceramic tool 21 for pressing an object to be heated, a ceramic heater 22 for heating the ceramic tool 21, and heat generated from the ceramic heater 22 is other than the ceramic tool 21. The ceramic heater 22 is composed of a heat insulating material 23 for preventing heat transfer to and a holder 24 that integrates these members and combines them with other members. An embedded heat generating portion 31 and a lead pattern 27 integrally joined to the heat generating portion 31 and connected to both ends of the heat generating body 26 on a belt-shaped ceramic body.
And a lead terminal 30 connected to the electrode lead-out portion 29. A pair of lead portions 28 in which the lead wires 28 are embedded, an electrode lead-out portion 29 in which a part of the lead pattern 27 is exposed from the side surface of each lead portion 28, and a lead terminal 30 connected to the electrode lead-out portion 29. (Japanese Patent Laid-Open No. 2001-3
No. 32589).

In the lead terminal 30, a lead wire 30b is attached to an L-shaped or plate-shaped electrode fitting 30a, and the electrode fitting 30a is brazed so as to cover the electrode lead-out portion 29. In this brazing material, Au-Ni having a Vickers hardness of 2.2 GPa (composition ratio: 82% by weight:
18% by weight, etc., and the brazing area is 15 m
It was about m ² .

[0006]

In recent years, in order to improve the production efficiency, it has been required to improve the heating temperature and temperature distribution of the contact heating device. Conventionally, it has been required to apply a power of about 1 kW to 100.
While the temperature was raised between ~ 300 ° C in about 4 seconds, it is currently required to apply a power of about 2.5 kW to rapidly raise the temperature between 100 ~ 500 ° C in less than 5 seconds. .

However, the ceramic heater 22 used in the conventional contact heating device has the electrode lead-out portion 29.
The lead terminal 30 joined to the above is brazed so as to cover a part of the lead portion 28, and when it is repeatedly used at a higher temperature, the temperature of the electrode lead-out portion 29 also becomes high, and a ceramic heater and a thermal heater with a small thermal expansion are used. Due to the difference in the coefficient of thermal expansion from the electrode fitting 30a having a large expansion, stress is generated in the brazing part during the operation of the contact heating device, and cracks easily form around the brazing part, which shortens the life of the heater. Was there.

Further, the ceramic heater 22 used in the conventional contact heating device has a structure in which the lead portion 28 is largely protruded in order to lower the temperature of the electrode lead-out portion 29, which is a hindrance structure in actual work. Was there.

The present invention has been devised in view of the above-mentioned drawbacks, and its purpose is to prevent the temperature rise of the electrode lead-out portion 29 of the ceramic heater 22 during repeated use at high temperature and to improve workability in a small space. It is to provide a compact and long-life contact heating device with high efficiency.

[0010]

A contact heating apparatus of the present invention is a ceramic tool for pressing an object to be heated, a ceramic heater for heating the ceramic tool, and heat generated from the ceramic heater. In addition to a heat insulating material for preventing heat transfer, a contact heating device composed of a holder for joining these members to other members, wherein the ceramic heater is
Built-in heat generating part having a built-in heat generating resistor, lead part having a conductive part connected to the heat generating resistor and extending substantially perpendicularly to the main surface of the ceramic heater, and a conductor part pulled out substantially vertically from the lead part And a recess surrounded by the heat generating part and the lead part, and the electrode extracting part of the ceramic heater is fixed to a holder via a heat insulating material.

The present invention is characterized in that the recess is filled with a heat insulating material.

The depth of the recess is 2 to 50 mm.

The electrode lead-out portion is provided with a hole having a tapered portion, a part of the conductor portion is exposed in the tapered portion, and a metallized portion is formed in the exposed portion.
It is characterized in that an electrode member is formed by providing an engaging member so as to come into contact with the metallized portion.

The recess is filled with a heat insulating material, and the depth of the recess is 2 to 50 mm.

Furthermore, the present invention is characterized in that the electrode lead-out portion is formed so as to come into contact with a heat insulating material.

Further, according to the present invention, a recess having a tapered portion is formed in the electrode lead-out portion, a part of the conductor portion is exposed in the tapered portion, and a metallized portion is formed in the exposed portion.
The electrode portion is formed so that the metallized portion contacts the engaging member.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

As shown in the perspective view of FIG. 1, the contact heating apparatus of the present invention is a ceramic tool 1 for pressing an object to be heated.
, A ceramic heater 2 for heating the ceramic tool 1, a heat insulating material 3 for preventing heat generated from the ceramic heater 2 from being transferred to a portion other than the ceramic tool 1, and integrating these members with each other. It is composed of a holder 4 for connecting to a member.

The ceramic tool 1 is composed of a silicon carbide based sintered body, a silicon nitride based sintered body, an aluminum nitride based sintered body, etc., and a vacuum drawing hole 1a for vacuum-sucking a semiconductor chip is formed on the upper surface thereof. And the ceramic heater 2, the heat insulating material 3, and the holder 4 which are arranged on the lower surface thereof.
Is also provided with a similar vacuum drawing hole, and since all the vacuum drawing holes are penetrated, the semiconductor chip on the upper surface of the ceramic tool 1 is vacuum-sucked by drawing a vacuum through them.

The ceramic tool 1 preferably has a thermal conductivity of 100 W / m · K or more,
The temperature of the peripheral portion of the ceramic tool 1 is prevented from lowering, the heat of the ceramic heater 2 is efficiently supplied to the ceramic tool 1 side, and the temperature distribution of the semiconductor chip mounted on the upper surface is kept constant. It is possible to effectively prevent variations in the bonding of the solder chips.

Further, a ceramic heater 2 is formed on the lower surface of the ceramic tool 1 and has a function of heating the semiconductor chip mounted on the upper surface of the ceramic tool 1.

The ceramic heater 2 is shown in FIG.
As shown in (a) and (b), a heating element 6 is formed on the ceramic body 5.
And a lead portion 8 having a built-in conductor portion 8a that is drawn out from the heating element 6 in a direction substantially perpendicular to the main surface of the ceramic heater 2 on the side of the heat generating portion 7; It is composed of an electrode lead-out portion 9 having a conductor portion 9a pulled out vertically, and has a recess 10 surrounded by the heat generating portion 7 and the lead portion 8. The electrode lead-out portion 9 of the ceramic heater 2 has a heat insulating material 3 interposed therebetween. Fixed to the holder 4.

The recess 10 suppresses the heat capacity of the ceramic heater 2 to enable rapid temperature rise and rapid temperature rise, and
Since the electrode lead-out portion 9 can be arranged on a surface different from the main surface of the heat generating portion 7 of the ceramic heater 2, a very simple structure capable of preventing the temperature rise of the electrode lead-out portion 9 can be obtained.

Here, the depth D of the recess 10 surrounded by the heat generating portion 7 and the lead portion 8 is preferably adjusted to 5 to 50 mm, and the recess 10 is filled with the heat insulating material 3. This is because if the depth D is less than 2 mm, the temperature of the electrode lead-out portion 9 becomes too high due to heat drawing of the heat generating portion 7, and if it exceeds 50 mm, the temperature reducing effect of the electrode lead-out portion 9 is sufficient and the manufacturing cost is low. This is because it will be too high. The depth D of the recess 10 is more preferably 5-5.
It is preferable to set it to 0 mm.

The thickness of the heating portion 7 of the ceramic heater 2 is preferably 1 to 4 mm, the thickness of the lead portion 8 is preferably 1 to 5 mm, and the thickness of the electrode lead-out portion 9 is preferably 1 to 10 mm. By properly adjusting the heat capacity of the heater, rapid heating and lowering performance of the heater temperature can be obtained. More preferably, the lead portion 8 has a thickness of 2 to 4 mm.

If the thickness of the heat generating portion 7 is less than 1 mm, the heat generating portion 7 is deformed when the ceramic tool 1 is pressed against the semiconductor chip, and the soldering to the semiconductor chip varies. The same applies when the thickness of the lead portion 8 is less than 1 mm. Further, if the thickness of the heat generating portion 7 exceeds 4 mm, the heat capacity of the heat generating portion 7 becomes too large and the cooling rate during cooling becomes slow, which is not preferable. Further, the thickness of the lead portion 8 is 5
If it exceeds mm, heat conduction through the lead portion 8 becomes large, the temperature of the electrode lead-out portion 9 rises, and cracks occur in the electrode lead-out portion 9, which is not preferable.

If the thickness of the electrode take-out portion 9 is less than 1 mm, the stress for fixing the contact heating device is applied to the electrode take-out portion 9, and the heat cycle of temperature increase / decrease is added. It is not preferable because 9 is easily damaged. Further, if the thickness of the electrode lead-out portion 9 exceeds 10 mm, the processing cost for forming the recess 10 increases, which is not preferable. Considering the processing cost,
The thickness of the electrode lead-out portion 9 is preferably 2 to 5 mm.

As a method for manufacturing such a ceramic heater 2, first, for example, 90 to 92 mol% of silicon nitride as a main component and 2 to 2 rare earth element oxides as a sintering aid are used.
10 mol%, aluminum oxide, and silicon oxide are added and mixed in an amount of 0.2 to 2.0% by weight and 1 to 5% by weight, respectively, with respect to the total amount of silicon nitride and rare earth element oxide to prepare a raw material powder. A powder is formed into a predetermined shape by a press forming method or the like to obtain a formed body, and the formed body is made of tungsten or molybdenum,
An appropriate organic solvent or solvent is added to and mixed with rhenium, etc., or their carbides, nitrides, etc. to prepare a conductive paste,
This is printed on the conductor shapes of the heating element 6 and the electrode lead-out portion 9 by screen printing or the like. Further, as shown in FIG. 2 (c), a through-hole is formed between the above-mentioned two molded bodies, and a molded body filled with a conductive paste is sandwiched therein to be in close contact with each other, and at a temperature of about 1650 to 1800 ° C. It is fired by hot press or fired at about 1700 to 1850 ° C. in a nitrogen atmosphere of 10 atm or more.

After grinding the obtained sintered body into a predetermined shape, a pair of electrode lead-out holes 11 are ground in the electrode lead-out portion 9 so that a part of the conductor portion 9a of the electrode lead-out portion 9 is formed into an electrode lead-out hole. And exposed on the surface of the electrode lead-out hole 11 as shown in FIG.
Alternatively, after applying a paste containing Ag-Cu and firing in a vacuum to form a metallized layer 12, and after applying a plating layer 13 made of Au, Pt, Ag, or Ni on the metallized layer 12 The ceramic heater 2 and the heat insulating material 3 are fixed by the engaging member 14, and the engaging member 1
The electrode lead-out portion 9 is formed by the contact between the metallized layer 4 and the metallized layer 12.

Since the metallized layer 12 contains a metal component having a high oxidation resistance as a main component and the plating layer 13 having a high oxidation resistance is formed on the surface thereof, the heat resistance of the electrode lead-out portion 9 is enhanced. In addition, since the electrode lead-out portion 9 is formed in contact with the engaging member 14, a large stress is less likely to be generated in the electrode lead-out portion 9 at the time of use at high temperature, and a defect such as a crack is not generated. Can be prevented.

If the engaging member 14 has a coefficient of thermal expansion intermediate between the coefficient of thermal expansion of the ceramic heater 2 and the coefficient of thermal expansion of the heat insulating material 3, the engaging member 14 may have a difference in coefficient of thermal expansion when the temperature rises. It is possible to prevent loosening of each member, a defect in electrical conduction, and the like.

The coefficient of thermal expansion of the engaging member 14 is 5 ×.
It is preferably made of an Fe-Ni-Co alloy of 10 ^-6 / ° C.

Further, since the engaging member 14 is formed of a countersunk screw and a nut, the fixing of each member and the electrical continuity of the electrode lead-out portion 9 can be reliably performed at low cost.

Further, as the structure of the electrode take-out portion 9, the contact type take-out structure has been described so far, but the metal fitting may be brazed.

The ceramic body 5 is preferably formed of a silicon nitride sintered body, and by embedding the heating element 6 and a conductor paste in the ceramic body 5, oxygen in the air up to the vicinity of the heating element 6 during operation can be obtained. Is diffused and the heating element 6
It effectively prevents oxidization and disconnection, and makes the high temperature strength extremely high to maintain the electrical insulation and durability.

Further, if the thermal conductivity of the ceramic body 5 is set to 50 W / mK or more at room temperature, the heat of the heating element 6 can be transferred to the entire ceramic body 5 in a short time, and the temperature unevenness can be prevented. If the thickness is set within the range of 1 to 2 mm, the heat capacity can be reduced and the temperature rising rate can be increased while maintaining high mechanical strength of the ceramic heater 2, so that the semiconductor bare chip is pressed. When heating and mounting on the wiring board, the ceramic heater 2 can be mounted in a short time without causing damage such as cracking.

The heat insulating material 3 provided on the lower surface of the ceramic heater 2 is made of mullite ceramics or mullite-cordierite ceramics having a porosity of about 5 to 30%. The heat of the ceramic heater 2 is transmitted to the ceramic tool 1 side. It acts to effectively transmit.

As for the structure of the heat insulating material 3, the concave portion 10 may be completely filled, or only the periphery of the vacuum drawing hole may be in contact with the ceramic heater 2. The reason why the periphery of the vacuum suction hole is in contact with the ceramic heater 2 is to improve the vacuum suction.

On the lower surface of the heat insulating material 3, there is formed a holder 4 for integrating the respective parts except the ceramic tool 1 and connecting them to other members. The holder 4 is made of metal or a ceramic member, but is preferably made of ceramics having a low thermal conductivity, and has the same or lower thermal conductivity as the ceramic body 5 forming the ceramic heater 2. It is sufficient that the thermal conductivity at room temperature is 50 W / m · K or less. Specifically, it is made of ceramics such as low thermal conductive silicon nitride, alumina and zirconia. Also,
In the case of a metal holder, a holder provided with a cooling mechanism such as air cooling is preferable.

In the contact heating device as described above, Joule heat is generated when electric power is applied by the electric resistance of the heating element 6 of the ceramic heater 2, and the semiconductor bare chip mounted on the upper surface of the ceramic tool 1 has a low melting point. This is a mechanism for generating heat at a temperature necessary for melting the low melting point brazing material when it is mounted on the wiring board via the brazing material.

The present invention is not limited to the above-mentioned embodiment, and various modifications can be made without departing from the gist of the present invention.

[0042]

EXAMPLES Examples of the present invention will be described below.

A ceramic heater 2 for a contact heating device as shown in FIG. 2 was produced and its characteristics were measured.

First, 90 to 92 mol% of silicon nitride as a main component, 2 to 10 mol% of a rare earth element oxide as a sintering aid, aluminum oxide and silicon oxide to silicon nitride and the total amount of rare earth element oxide as a sintering aid. After adjusting the raw material powder by adding and mixing 0.2 to 2.0 wt% and 1 to 5 wt% respectively, the raw material powder is obtained by a press molding method or the like to obtain a 30 mm × 50 mm compact, and the upper surface of the compact A heating element paste is prepared by mixing tungsten with an appropriate organic solvent and a solvent, and this is printed on the conductor shapes of the heating portion 7 and the electrode lead-out portion 9 by a screen printing method or the like. Further, a through-hole is formed between the above-mentioned two molded bodies, and a molded body filled with a conductive paste containing tungsten as a main component is sandwiched and closely adhered thereto, and hot press firing is performed at a temperature of about 1650 to 1800 ° C. After that, it is ground into a predetermined shape having a concave portion 10 surrounded by the heat generating portion 7 and the lead portion 8, and a pair of electrode lead-out holes 11 is separately ground to expose a part of the conductor portion from the electrode lead-out hole 11. To form the electrode lead-out portion 9,
A plating layer 1 made of Ni is formed by applying a paste containing Ag-Cu and firing it in a vacuum to form a metallized layer 12.
After applying 3, the ceramic heater 2, the heat insulating material 3 and the holder 4 are assembled with the engaging member, and at this time, the electrode take-out portion 9
Is in contact with the heat insulating material 3.

The ceramic heater 2 is processed by using a surface grinder and an ultrasonic processing machine, and is 24 mm × 24 mm.
Ceramic body 5 with a heating surface main surface and screw part diameter 3 mm
Then, the electrode lead-out hole 11 having a tapered portion was formed.
Further, the thickness of the heating portion 7 of the ceramic heater 2 is 2 m.
m, the thickness of the lead portion 8 and the electrode lead-out portion 9 is 3 mm
Then, a sample was obtained in which the depth D of the recess 10 surrounded by the heat generating portion 7 and the lead portion 8 was 1 to 50 mm as shown in Table 1.

The ceramic heater 22 having the conventional structure shown in FIG.
4 mm x 24 mm heat generating part 31 and length 20 to 50 mm
Was formed, a metallized layer containing Ag—Cu was formed, the electrode fitting 30a was brazed with Ag—Cu, and the lead wire 30b was connected to obtain a sample.

The temperature of the electrode part is measured by attaching a thermocouple.
The temperature of the electrode lead-out portion 9 is measured by applying power to the ceramic heaters 2 and 22 so that the temperature of the heat generating portion is saturated at around 500 ° C. It was confirmed by checking the change in resistance value and the binocular appearance.

The results are shown in Table 1.

[0049]

[Table 1]

From the results shown in Table 1, No. 1 in which the depth D of the recess 10 surrounded by the heat generating portion 7 and the lead portion 8 was 1 mm. 1 is
The temperature of the electrode lead-out portion 9 became 400 ° C. or higher, and cracks were generated in the electrode lead-out portion 9. On the other hand, the heat generating part 7
A recess 10 having a depth D of 2 mm or more surrounded by the lead portion 8
No. In Nos. 2 to 9, no crack was generated in the electrode take-out portion 9. In particular, it has been found that when the depth D of the recess 10 is 3 mm or more, the temperature of the electrode take-out portion 9 can be 350 ° C. or less even when the temperature of the ceramic heater is as high as 500 ° C. Further, the depth D of the recess 10 is 5 m.
It has been found that the temperature of the electrode lead-out portion 9 can be set to 300 ° C. or lower if the temperature is set to m or more.

[0051]

According to the contact heating apparatus of the present invention, a ceramic tool for pressing an object to be heated, a ceramic heater for heating the ceramic tool, and heat generated from the ceramic heater are transferred to other than the ceramic tool. A contact heating device comprising a heat-insulating material for preventing the heat generation and a holder for connecting these members to another member, wherein the ceramic heater includes a heat-generating portion containing a heat-generating resistor and the heat-generating portion. A lead portion that is connected to the resistor and has a built-in conductor portion that extends substantially perpendicularly to the main surface of the ceramic heater, an electrode lead-out portion that has a conductor portion that is pulled out substantially vertically from the lead portion, and the heating portion and the lead portion. Since it has a recess surrounded by, and the electrode extraction part of the ceramic heater is fixed to the holder via a heat insulating material, it can be repeated at high temperatures. In use, to prevent the temperature rise of the electrode extraction portion of the ceramic heater, a high lifetime contact heating apparatus with high operability compact with a small occupied volume came to be obtained.

Further, according to the present invention, a recess having a tapered portion is formed in the electrode lead-out portion, a part of the conductor portion is exposed in the tapered portion, and a metallized portion is formed in the exposed portion.
Since the electrode portion is formed so that the metallized portion comes into contact with the engaging member, the heat resistance of the electrode portion is high at high temperatures and cracks in the electrode lead portion can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a contact heating device of the present invention.

FIG. 2 (a) is a perspective view of a ceramic heater used in the contact heating apparatus of the present invention, and FIG. 2 (b) is the same figure (a).
2C is a cross-sectional view, and FIG. 3C is an exploded perspective view before external processing.

FIG. 3 is a cross-sectional view of a ceramic heater electrode extraction portion of the contact heating device of the present invention.

FIG. 4 is a perspective view showing a conventional contact heating device.

FIG. 5A is a perspective view showing a ceramic heater used in a conventional contact heating device, and FIG. 5B is an exploded perspective view of the same.

[Explanation of symbols]

1: Ceramic tool 2: Ceramic heater 3: Thermal insulation 4: Holder 5: Ceramic body 6: heating element 7: Heating part 8: Lead section 9: Electrode take-out part 10: Recess 11: Electrode drawing hole 12: Metallized layer 13: plating layer 14: Engagement member

Claims (4)

[Claims] 1. A ceramic tool for pressing an object to be heated, a ceramic heater for heating the ceramic tool, and heat insulation for preventing heat generated from the ceramic heater from being transferred to other than the ceramic tool. A contact heating device comprising a material and a holder for connecting these members to another member, wherein the ceramic heater includes a heating portion containing a heating resistor and a ceramic heater connected to the heating resistor. A lead portion containing a conductor portion extending substantially vertically to the main surface, an electrode lead-out portion containing a conductor portion pulled out substantially vertically from the lead portion, and a recess surrounded by the heat generating portion and the lead portion, A contact heating device characterized in that the electrode take-out portion of the ceramic heater is fixed to a holder via a heat insulating material. 2. The contact heating apparatus according to claim 1, wherein the recess is filled with a heat insulating material. 3. The contact heating device according to claim 1, wherein the recess has a depth of 2 to 50 mm. 4. A hole having a tapered portion is provided in the electrode lead-out portion, a part of the conductor portion is exposed in the tapered portion, and a metallized portion is formed in the exposed portion so as to come into contact with the metallized portion. The contact heating device according to claim 1, wherein the electrode portion is formed by providing an engaging member.