Power heating member

A heating member for processing an object to be processed in contact therewith by heat generated upon power supply, comprising a conductive substrate, and an insulating layer formed at least at that portion of the conductive substrate which is brought into contact with the object to be processed. The insulating layer has a specific resistance 100 times or more that of the conductive substrate, or of at least 10.sup.-2 .OMEGA..cm. The insulating layer prevents a shunt current flowing from the heating member to the object to be processed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a power heating member for processing an 
object to be processed such as a lead wire by the Joule heat generated 
upon electric power supply. 
2. Description of the Related Art 
In recent years, factory automation has significantly progressed. For 
example, an apparatus for soldering a lead wire of an IC to a substrate is 
available. In this apparatus, a heating member consisting of a conductive 
material such as Fe, Mo, W, Ta, Cu, Al or stainless steel generates Joule 
heat upon power supply and urges a plurality of lead wires against a 
substrate at the same time, thereby soldering the lead wires to the 
substrate. Lead wires normally extend from an IC in two or four 
directions. Therefore, two or four heating members are arranged to oppose 
each other at two sides of an IC or to surround four sides of the IC. 
These heating members are electrically connected in series with each 
other. Although the heating members may be connected in parallel with each 
other, a current capacity required for the entire apparatus is increased 
in this case. 
When the heating members consisting of a conductive material are directly 
brought into contact with lead wires of an IC to perform soldering, 
however, wiring of a substrate is brought into contact with the 
series-connected heating members, and the heating members are connected 
with each other via the wiring. In this case, a shunt current flows from 
the heating members to the wiring of the substrate. As a result, the 
wiring of the substrate is undesirably disconnected. 
SUMMARY OF THE INVENTION 
It is an object of the present invention to provide a power heating member 
for generating Joule heat upon power supply and processing an object in 
contact therewith such as a lead wire by the Joule heat, which can prevent 
a shunt current flowing from the heating member to the object to be 
processed. 
It is another object of the present invention to provide a method of 
processing an object in contact therewith such as a lead wire by using 
Joule heat generated by a heating member upon power supply, which can 
process the object to be processed without causing a shunt current to flow 
from the heating member to the object to be processed. 
According to the present invention, there is provided a heating member for 
processing an object to be processed in contact therewith by heat 
generated upon power supply, comprising a conductive substrate, and an 
insulating layer formed at least at that portion of the conductive 
substrate which is brought into contact with the object to be processed. 
The insulating layer has a specific resistance 100 times or more that of 
the conductive substrate. 
The insulating layer formed on the conductive substrate may be an 
insulating region formed by modifying a surface region of the substrate or 
an insulating film formed on the surface of the substrate. 
In addition, according to the present invention, there is provided a power 
heating member for processing an objected to be processed in contact 
therewith by heat generated upon power supply, comprising a conductive 
substrate, and an insulating layer formed at least at that portion of the 
conductive substrate which is brought into contact with the object to be 
processed. The insulating layer has a specific resistance of 10.sup.-2 
.OMEGA..cm or more. 
Also, according to the present invention, there is provided a method of 
processing an object to be processed comprising the steps of supplying 
power to a conductive substrate of a heating member comprising the 
conductive substrate, and a processing part consisting of an insulating 
layer formed at least at a portion of the conductive substrate and having 
a specific resistance 100 times or more that of the conductive substrate 
or a specific resistance of 10.sup.-2 .OMEGA..cm or more; bringing the 
processing part of the heating member into contact with the object to be 
processed before, after or simultaneously with the power supply; and 
processing the object to be processed by heat generated upon the power 
supply.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
A preferred embodiment of the present invention will be described in detail 
below with reference to the accompanying drawings. 
FIG. 1 is a perspective view showing a heating member of the present 
invention for use in a soldering apparatus. 
Referring to FIG. 1, a heating member 13 has a shape as shown in FIG. 1 in 
order to shorten a time required for increasing or decreasing a 
temperature upon power supply or heat radiation, respectively. An 
insulating layer is formed on the surface of the heating member 13 
especially on its bottom surface which will be brought into contact with a 
lead wire of an IC and wiring of a substrate. 
In a first embodiment of the present invention, a specific resistance of 
the insulating layer formed on the surface of a substrate of the heating 
member 13 is 100 times or more that of the substrate. 
The insulating layer may be a region which contains a larger amount of at 
least one element selected from the group consisting of silicon, carbon, 
oxygen, nitrogen, germanium, zirconium, yttrium, and Group III and V 
elements of the Periodic Table than that in the substrate. 
Since a temperature is increased/decreased at a period of several seconds 
in an automatic soldering apparatus, the material of the insulating layer 
must have high thermal conductivity. Therefore, when the insulating layer 
is an insulating film having a film thickness exceeding 1 lm, the thermal 
conductivity must be 1 Wm.sup.-1 K.sup.-1 or more. Silicon, germanium and 
graphite having high thermal conductivities may be employed. In addition, 
although the thermal conductivity of a nitride or carbide of silicon or 
germanium is higher in a crystalline state, it is still considerably high 
in an amorphous state. Also any material containing the above-mentioned 
elements has high thermal conductivity. 
In order to form an insulating layer on the surface or surface region of a 
substrate, a substrate consisting of a conductive material is heated in a 
nitrogen, hydrocarbon or oxygen atmosphere up to 500.degree. C. or more to 
cause the substrate to contain the element. Alternatively, ion 
implantation, sputtering, ion plating, vacuum deposition, plasma CVD, ECR 
plasma CVD, thermal CVD or optical CVD may be used. 
When ion implantation is used, an insulating layer is formed on a surface 
region of a substrate although its boundary may be not clear. When any of 
the remaining methods is used, an insulating film is formed on the surface 
of a substrate. 
When the element contained in the insulating layer is carbon, oxygen or 
nitrogen, the layer may become weak if the content of the element is 
increased. In this case, therefore, the content of the element is 
preferably 0.01 to 20 at %. The content of zirconium, yttrium, gallium, 
silicon or germanium is preferably 50 at % or less. 
Since the heating material has a potential difference of about 1 to 10 V 
with respect to the ground potential, the insulating layer requires a film 
thickness not causing insulation breakdown against the voltage. 
Therefore, the thickness of the insulating layer is preferably 500 .ANG., 
and more preferably 1,000 .ANG. or more. In consideration of the thermal 
conductivity, an upper limit of the thickness is preferably 5 mm when the 
insulating layer is an insulating region, and is preferably 5 .mu.m when 
it is an insulating film. 
In a second embodiment of the present invention, a specific resistance of 
an insulating layer formed on the surface of a substrate is 10.sup.-2 
.OMEGA..cm or more. 
More specifically, the material of the insulating layer comprises at least 
one element selected from the group consisting of silicon, carbon, oxygen, 
nitride, and germanium, and Group III elements of the Periodic Table. The 
reason for this is as follows. That is, the insulating layer must consist 
of a material which is not peeled from the substrate in a heating cycle of 
about 150.degree. to 300.degree. C. In addition, since the temperature of 
the heating member is increased/decreased at a period of several seconds 
in an automatic soldering apparatus, the material of the insulating layer 
must have high thermal conductivity. Therefore, when the thickness of the 
insulating layer exceeds 1 .mu.m, the thermal conductivity must be 1 
wm.sup.-1 k.sup.-1 or more. Silicon, germanium and graphite have high 
thermal conductivities. In addition, although the thermal conductivity of 
a nitride or carbide of silicon or germanium is higher in a crystalline 
state, it is still considerably high in an amorphous state. Also, any of 
the above-mentioned materials has high conductivity. 
The film thickness of the insulating layer is preferably 500 .ANG. or more, 
and more preferably 1,000 .ANG. or more. In consideration of an abrasion 
resistance, the thickness is most preferably about 2 .mu.m. In 
consideration of the thermal conductivity, a thickness of 5 .mu.m or more 
is not preferable. 
The insulating layer is formed on the surface of the substrate by 
sputtering, ion plating, vacuum deposition, plasma CVD, ECR plasma CVD, 
thermal CVD, optical CVD or the like. Of these methods, plasma CVD and ECR 
plasma CVD are most suitable because the adhesion strength of the film is 
good, the film can be formed at a comparatively low temperature and 
therefore characteristics of the film are not degraded, and electrical 
characteristics of the film can be easily controlled. 
In the automatic soldering apparatus, four heating members manufactured as 
described above are arranged to surround four sides of an IC, as shown in 
FIG. 2. These heating members are electrically connected in series with 
each other to an AC power source of 50 Hz. 
A soldering process using the heating members arranged as shown in FIG. 2 
is performed as follows. When an IC placed on a substrate is automatically 
conveyed, the heating members 13 descend to urge lead wires of the IC with 
a pressure of about 2 kg/cm.sup.2. At the same time, a current of about 
500 .ANG. is supplied to the heating members 13 to heat them up to about 
300.degree. C. After a solder is melted and the lead wires are connected 
to circuits of the substrate, power supply is stopped, and the heating 
members 13 then move upward after the solder is solidified. In this 
manner, one cycle of soldering is completed. 
Various examples of manufacturing the heating member according to the 
present invention by forming an insulating layer on or in the surface of a 
substrate consisting of a conductive material will be described below. 
EXAMPLE 1 
In this example, as listed in Table 1, each of eight types of insulating 
films was formed on a substrate by plasma CVD. FIG. 3 is a schematic view 
showing a capacitance-coupled plasma CVD apparatus of a parallel plate 
type used in formation of an insulating film in this example. A plate-like 
ground electrode 7 and an RF electrode 8 are located in a vacuum chamber 
6. A heater 9 is connected to the ground electrode 7. The RF electrode 8 
is connected to an RF power source 11 via a matching box 10. A gas inlet 
port 12 is formed in the chamber 6. 
In order to form an insulating film on the conductive heating member 13 by 
using the above apparatus, the heating members 13 were loaded on the 
ground electrode 7, and the chamber 6 was evacuated by a vacuum pump (not 
shown) to about 10.sup.-3 Torr. Each heating member 13 was heated up to 
about 150.degree. to 450.degree. C. by the heater 9 connected to the 
ground electrode 7, a source gas such as SiH.sub.4, N.sub.2, CH.sub.4 or 
the like was supplied to the chamber 6, and the chamber 6 was evacuated to 
maintain a vacuum degree of 0.05 to 1.0 Torr therein. When power was 
supplied to the RF electrode 8, a glow discharge was induced between the 
electrodes 7 and 8, and a plasma of the source gas formed a thin 
insulating film on the surface of the heating member 13. The types of 
source gas and film formation conditions are listed in Table 1. For 
example, a film having an SiCN composition was formed by supplying, as a 
source gas, 100 SCCM of SiH.sub.4, 500 SCCM of N.sub.2 and 400 SCCM of 
CH.sub.4 from the gas inlet port 12, and applying a voltage of 500 W to 
the RF electrode 8 while a reaction pressure in the chamber 6 was 
maintained at 1.0 Torr. 
In this case, a 3.0-.mu.m thick film was formed with a film formation time 
of 40 minutes. 
Insulating films of other compositions were similarly formed, and 
components, types and flow rates of the source gases, reaction pressures 
in the chamber, powers to be applied to the RF electrodes 8, film 
formation times, film thicknesses, and specific resistances for the 
respective films are as listed in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Film Component 
SiCN SiC SiO SiN AIN BN BC BCN 
__________________________________________________________________________ 
Source Gas 
Flow Rate 
SiH.sub.4 /100 
SiH.sub.4 /50 
SiH.sub.4 /50 
SiH.sub.4 /100 
Al.sub.2 /(CH.sub.3).sub.3 /20 
B.sub.2 H.sub.6 /20 
B.sub.2 H.sub.6 /20 
B.sub.2 H.sub.6 /20 
(SCCM) N.sub.2 /500 
CH.sub.4 /300 
O.sub.2 /300 
N.sub.2 /800 
N.sub.2 /50 
N.sub.2 /50 
CH.sub.4 /30 
CH.sub.4 /20 
CH.sub.4 /300 N.sub.2 /50 
Reaction Pressure 
1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 
(Torr) 
RF Power (W) 
500 500 500 500 800 500 500 500 
Film Formation 
40 40 40 40 40 30 30 30 
Time (min.) 
Film Thickness 
3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 
(.mu.m) 
__________________________________________________________________________ 
Film Component 
Al.sub.2 O.sub.3 
W C (Diamond) 
GeO Ge GeN GeC 
__________________________________________________________________________ 
Source Gas 
Flow Rate 
Al.sub.2 /(CH.sub.3).sub.3 /20 
WF.sub.6 /20 
CH.sub.4 /30 
GeH.sub.4 /120 
GeH.sub. 4 /100 
GeH.sub.4 /120 
Ge.sub.4 /120 
(SCCM) O.sub.2 /300 
CH.sub.4 /250 
O.sub.2 /200 
N.sub.2 /800 
CH.sub.4 /300 
Reaction Pressure 
1.0 1.0 20 1.0 1.0 1.0 1.0 
(Torr) 
RF Power (W) 
800 1000 1500 500 300 500 800 
Film Formation 
60 60 60 40 60 40 60 
Time (min.) 
Film Thickness 
3.0 3.0 2.0 3.0 3.0 3.0 3.0 
(.mu.m) 
__________________________________________________________________________ 
According to plasma CVD, the heating member can be processed at a 
comparatively low temperature of 150.degree. to 450.degree. C. Therefore, 
a film strongly adhered on a substrate can by formed without degrading 
characteristics of the heating member. 
EXAMPLE 2 
In this example, a portion having a high specific resistance was formed in 
the surface region of a substrate by an ion implantation apparatus as 
shown in FIG. 4. A solid member 14 as a source was placed in an oven 15, 
and a reaction gas was supplied therein. A current was then flowed through 
a filament 17 to heat it, so that the reaction gas liberated and ionized 
elements in the source solid member. The generated ions were focused by a 
focus 18 and accelerated by an accelerator 19. Subsequently, a magnetic 
field is applied by a magnet 20 so that only a desired type of ions were 
extracted from the liberated ions through a slit 21. Electric fields were 
then applied by Y-and X-scanners 22 and 23. The ions which acquired a high 
energy by the magnetic and electric fields were radiated on and implanted 
in a conductive substrate 13. 
Examples of the ion to be implanted by ion implantation are nitrogen, 
carbon, oxygen, phosphorus, boron, indium, yttrium, silicon and germanium. 
When a large amount of zirconium, yttrium, gallium, silicon or germanium 
is contained, not only a specific resistance is increased, but also an 
abrasion resistance is improved. As a result, a power heating member which 
can be used several ten thousand times can be manufactured. 
In addition, as shown in FIG. 5, when a portion having a high specific 
resistance is formed on only a portion (hatched portion) of a heating 
member to be directly brought into contact with an object to be processed, 
heat is generated mainly at this portion having a high specific 
resistance, and only a small amount of current is required as a whole. 
That is, a portion of a substrate in which no ions are implanted serves as 
a current supply terminal, and its ion-implanted portion serves as a 
heater. The depth of the portion having a high specific resistance is 
preferably 1,000 .ANG. to 5 mm. 
EXAMPLE 3 
In this example, films having components listed in Table 2 were formed by 
sputtering. A sputtering apparatus used in this example is shown in FIG. 
6. A plate-like ground electrode 7 and an RF electrode 8 are arranged to 
oppose each other in a vacuum chamber 6, and a heater 9 is connected to 
the ground electrode 7. The RF electrode 8 is connected to an RF power 
source 11 via a matching box 10. A gas inlet port 12 is formed in a side 
wall of the chamber 6. This sputtering apparatus is similar to the plasma 
CVD apparatus shown in FIG. 3 except that a solid member of a source 
material is placed as a target 14 in the RF electrode 8. In order to form 
an insulating film by using this apparatus, a solid member of a source 
material was placed as the target 14, and an Ar gas, and if necessary, a 
reaction gas were simultaneously supplied from the gas inlet port 12. 
After Ar ions in plasmas of these gases liberated the substance of the 
target 14 in an atomic or molecular state, an insulating film was formed 
on the surface of a heating member 13 by a reaction in the plasma of the 
reaction gas. Film components, types of source material, film formation 
conditions and the like of the formed films are listed in Table 2. For 
example, a film consisting of amorphous silicon was formed by using 
monocrystalline or polycrystalline silicon as a target, supplying 10 SCCM 
of an Ar gas and 100 SCCM of an H2 gas from the gas inlet port 12, and 
applying a voltage of 500 W to the RF electrode 8 while the pressure in 
the chamber was maintained at 1.times.10.sup.-3 Torr. In this case, a 
3.0-.mu.m thick amorphous silicon film was formed with a film formation 
time of 60 minutes. Alternatively, 1 SCCM of a B.sub.2 H.sub.6 gas or PH 
gas may be supplied as a source gas together with the Ar and H.sub.2 
gases. Films of other components were similarly formed, and types of solid 
member used as a target, types and flow rates of source gases, reaction 
pressures in the chamber 6, powers applied to the RF electrode 8, film 
formation times, and film thicknesses for the respective films are listed 
in Table 2. 
A film formation method adopting sputtering is advantageous because a solid 
member which can be easily handled can be used as a source material and 
the shape of the apparatus need not be changed in accordance with that of 
the heating member. 
TABLE 2 
__________________________________________________________________________ 
Film Amorphous Silicon Silicon 
Component 
Amorphous Silicon 
Germanium Carbide Nitride 
SiO.sub.2 
TiN 
__________________________________________________________________________ 
Target 
Monocrystalline Monocrystalline 
Sintered Sintered 
SiO.sub.2 
TiN 
or Polycrystal- or Polycrystal- 
Silicon Silicon 
line Silicon line Germanium 
Carbide Nitride 
Source 
Gas 
Flow Rate 
Ar/10 Ar/10 
Ar/10 Ar/10 Ar/10 
Ar/10 Ar/10 
Ar/10 
Ar/10 Ar/10 
(SCCM) 
H.sub.2 /100 
H.sub.2 /100 
H.sub.2 /100 
H.sub.2 /100 CH.sub.4 /50 
NH.sub.3 /50 
N.sub.2 /50 
B.sub.2 H.sub.6 /1 
PH.sub.3 /1 
Reaction 
1 .times. 10.sup.-3 
1 .times. 10.sup.-3 
1 .times. 10.sup.-3 
1 .times. 10.sup.-3 
1 .times. 10.sup.-3 
1 .times. 10.sup.-3 
1 .times. 10.sup.-3 
1 .times. 10.sup.-3 
1 .times. 10.sup.-3 
1 .times. 
10.sup.-3 
Pressure 
(Torr) 
RF Power 
500 500 500 500 500 500 500 500 500 800 
(W) 
Film 60 60 60 60 120 120 80 80 80 60 
Formation 
Time (min) 
Film 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 
Thickness 
(.mu.m) 
__________________________________________________________________________ 
Film 
Component 
AlN Al.sub.2 O.sub.3 
BN GeC GeN GeO 
__________________________________________________________________________ 
Target 
Sintered 
Sintered 
Crystal- 
Sintered 
Monocrys- 
Sintered 
Sintered 
GeO.sub.2 
AlN Al.sub.2 O.sub.3 
line BN 
GeC talline Ge 
GeN GeN 
Source 
Gas 
Flow Rate 
Ar/10 Ar/10 Ar/10 Ar/10 Ar/10 Ar/10 Ar/10 Ar/10 
(SCCM) 
NH.sub.3 /50 CH.sub.4 /50 
NH.sub.3 /50 
Reaction 
1.0 .times. 10.sup.-3 
1.0 .times. 10.sup.-3 
1.0 .times. 10.sup.-3 
1.0 .times. 10.sup.-3 
1.0 .times. 10.sup.-3 
1.0 .times. 10.sup.-3 
1.0 .times. 10.sup.-3 
1.0 .times. 
10.sup.-3 
Pressure 
(Torr) 
RF Power 
800 800 800 500 500 500 500 500 
(W) 
Film 60 120 60 120 120 80 80 80 
Formation 
Time (min) 
Film 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 
Thickness 
(.mu.m) 
__________________________________________________________________________ 
EXAMPLE 4 
In this example, an insulating film was formed by ECR plasma CVD. An 
apparatus used in this method is as shown in FIG. 7. A gas inlet pipe 12 
is formed in a side wall of a film formation chamber 15. A plasma 
formation chamber 16 is located on the film formation chamber 15. The 
chambers 15 and 16 communicate with each other via a plasma inlet port 18 
formed in a partition 17. A quartz plate 19 is located on the upper wall 
of the plasma formation chamber 16, and a microwave waveguide 20 is 
located above the quartz plate 19. A gas inlet pipe 21 is formed in the 
upper wall of the chamber 16. An electromagnet 22 surrounds the chamber 
16. 
In order to form an insulating film on a heating member by using the above 
apparatus, heating members 13 were placed on a bottom portion of the film 
formation chamber 15, and film formation was performed as follows. The 
chamber 15 was evacuated by a vacuum pump to maintain a vacuum degree of 
1.times.10.sup.-4 to 5.times.10.sup.-3. A source gas was supplied from the 
inlet pipe 12 to the film formation chamber 15, and a reaction gas (e.g., 
N.sub.2, O.sub.2 or CH.sub.4) or a gas (Ar, He or -H.sub.2) reactive 
itself but supplying an energy to--another was supplied from the inlet 
pipe 21 to the plasma formation chamber 16. A 2.45-GHz microwave was 
supplied to the plasma formation chamber 16 to generate an electric field 
E. In addition, a current was flowed through the electromagnet 22 to form 
a 875-G (gauss) magnetic field B in the chamber 16. When electrons in the 
chamber 16 resonated and were excited, an energy of the electrons was 
applied to the N2 or Ar gas supplied from the pipe 21, thereby forming a 
plasma of the gas. The plasma was extracted from the plasma inlet port 18 
to the film formation chamber 15 as the magnetic field diffused. The 
source gas supplied from the pipe 12 to the chamber 15 was decomposed by 
the plasma to cause a reaction. In this manner, a film consisting of the 
component of the reaction gas was formed on the surface of each plate-like 
heating member 13 placed in the film formation chamber 15. The types of 
reaction gas, film formation conditions and the like of the individual 
films are listed in Table 3. For example, a film of an SiN was formed by 
supplying 10 SCCM of SiH.sub.4 as a source gas from the gas inlet pipe and 
50 SCCM of an N.sub.2 gas was supplied as a reaction gas from the gas 
inlet pipe. The pressure in the chamber was maintained at 
3.times.10.sup.-4 Torr, and the microwave power was set at 500 W. In this 
case, a 3.0-.mu.m thick film was formed with a film formation time of 40 
minutes. Films of other components were similarly formed, and types and 
flow rates of the source gases, reaction pressures in the chamber 16, 
microwave powers, film formation times, film thicknesses, and specific 
resistances for the respective films are listed in Table 3. As described 
above, according to ECR plasma CVD, the heating member can be processed 
without heating it. Therefore, a film having a uniform component can be 
strongly adhered on the member. 
TABLE 3 
__________________________________________________________________________ 
Film 
Component 
SiN SiC SiO TiN TiC TiCN BN BC BCN 
__________________________________________________________________________ 
Source 
Gas 
Flow Rate 
SiH.sub.4 /10 
SiH.sub.4 /10 
SiH.sub.4 /10 
TiCl4/10 
TiCl4/10 
TiCl4/10 
B.sub.2 H.sub.6 /10 
B.sub.2 H.sub.6 /10 
B.sub.2 H.sub.6 /10 
(SCCM) 
Reaction 
Gas 
Flow Rate 
N.sub.2 /50 
CH.sub.4 /30 
O.sub.2 /30 
N.sub.2 /50 
CH.sub.4 /30 
CH.sub.4 /20 
N.sub.2 /50 
CH.sub.4 /30 
CH.sub.4 /30 
(SCCM) H.sub.2 /200 
H.sub.2 /200 
N.sub.2 /50 N.sub.2 /50 
H.sub.2 /200 
Reaction 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
Pressure 
(Torr) 
Microwave 
500 500 500 1000 1000 1000 500 500 500 
Power (W) 
Film Forma- 
40 40 40 60 60 60 30 30 30 
tion Time 
(min) 
Film Thick- 
3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 
ness (.mu.m) 
__________________________________________________________________________ 
Film 
Component 
Al.sub.2 O.sub.3 
AlN WC 
__________________________________________________________________________ 
Source 
Gas 
Flow Rate 
Al(CH.sub.3).sub.3 /10 
Al(CH.sub.3).sub.3 /10 
WF.sub.6 /10 
(SCCM) 
Reaction 
Gas 
Flow Rate 
O.sub.2 /30 
N.sub.2 /30 
CH.sub.4 /50 
(SCCM) 
Reaction 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
3 .times. 10.sup.-4 
Pressure 
(Torr) 
Microwave 
800 800 1000 
Power (W) 
Film Forma- 
60 60 60 
tion Time 
(min) 
Film Thick- 
3.0 3.0 3.0 
ness (.mu.m) 
__________________________________________________________________________ 
When Ar ion bombardment is performed before the film formation methods in 
any of Examples 1, 3 and 4, adhesion strength between a film and a 
substrate can be further increased. In order to perform this processing in 
plasma CVD or ECR plasma CVD, Ar is flowed to form a plasma without 
supplying a source gas for forming a film. In sputtering, this processing 
is performed by applying a power not to a target but to a substrate. 
In order to increase the adhesion strength between a film and a substrate 
in any of Examples 1, 3 and 4, a region containing a larger amount of 
nitrogen, carbon, oxygen or the like than that in the substrate may be 
formed in an interface between the film and the substrate. For this 
purpose, an insulating film may be formed on a substrate which is 
subjected to ion nitriding or carburizing beforehand, or a gas of N.sub.2, 
O.sub.2, CH.sub.4 or the like may be mixed in an Ar gas upon ion 
bombardment. Alternatively, ion bombardment of a gas of N.sub.2, O.sub.2, 
CH.sub.4 or the like may be performed. 
The insulating layer formed in any of the above examples has many 
advantages. For example, the insulating layer has high abrasion and 
oxidation resistances and therefore can be used even several ten thousand 
times, and a solder hardly adheres on the heating member. 
As has been described above, according to the heating member of the present 
invention, an insulating layer is formed on a portion to be brought into 
contact with an object to be processed. Therefore, a shunt current does 
not flow from the heating member to the object to be processed, thereby 
solving problems of, e.g., disconnection of wiring.