Abstract: A ceramic heater making it possible to prevent a short circuit in its resistance heating element and heat a semiconductor wafer evenly. The ceramic beater includes a ceramic substrate, an insulating layer having volume resistivity higher than that of the ceramic substrate, being formed on at least a part of the ceramic substrate, and a resistance heating element formed on the insulating layer.

Abstract: A ceramic heater for a semiconductor producing/examining device including a ceramic substrate having a disc form with a diameter exceeding 200 mm and first and second surfaces, the first surface being a wafer-holding face and the second surface opposing to the first surface, the wafer-holding face being such that a semiconductor wafer is directly put on the wafer-holding face or held apart from the wafer-holding face by a supporting pin. The wafer-holding face has a surface roughness Rmax of 0.1 to 250 ?m according to JIS R 0601, and a difference between the surface roughness of the wafer-holding face and surface roughness of the second surface is 50% or less.

Abstract: An object of the present invention is to provide a ceramic heater for a semiconductor producing/examining device which is capable of accurately measuring the temperature of an object to be heated and evenly heating the whole body of a silicon wafer by adjusting the heating state of a heating element based on the temperature measurement result, and the ceramic heater for a semiconductor producing/examining device of the present invention is a ceramic heater including a ceramic substrate and a heating element formed on the surface or the inside of the ceramic substrate, wherein a temperature measurement element is formed while being brought into contact with the ceramic substrate and the surface roughness of the ceramic substrate brought into contact with the temperature measurement element is Ra?5 ?m.

Abstract: It is a an object of the present invention to provide a ceramic substrate for a semiconductor producing/examining device which has high fracture toughness value, exellent thermal shock resistivity, high thermal conductivity and an excellent temperature rising and falling properties, and is preferable as a hot plate, an electrostatic chuck, a wafer prober and the like. A ceramic substrate, for a semiconductor producing/examining device, having a conductor formed inside thereof or on the surface thereof of the present invention is the ceramic substrate, wherein said ceramic substrate has been sintered such that a fractured section thereof exhibits intergranular fracture.

Abstract: A supporting structure for attaching a ceramic susceptor into a processing chamber is provided. The ceramic susceptor is used for placing and heating an article to be processed. The supporting structure has one or more supporting projections integrally provided on a back face of the ceramic susceptor and one or more supporting members mounted to the processing chamber and separated from the supporting projections. At least a part of the supporting member is made from a heat-insulating material and the supporting projection is attached to the supporting member by mechanical means.

Abstract: A heating system 25 has a main electric heat-generating element 3 and a heating surface 4a for heating an object, auxiliary electric heat-generating elements 5A to 5D, and a main power source 1 for supplying power to the main heating element. The system 25 further has an auxiliary power source 2 for supplying power to the auxiliary heating elements, and a power source controller for controlling the power supplied to the main heating element and to the auxiliary heating elements respectively and independently. Power supplied to the main heating element 3 is controlled by the controller within a first power range and power supplied to the auxiliary heating elements is controlled by the controller within a second power range. The second power range has a width smaller than that of the first power range so as to control temperature distribution on the heating surface 4a.

Abstract: By indirectly monitoring a warping amount of a substrate, it is possible to examine causes easily when substrate processing such as deposition is performed with nonuniform in-plane temperature of the substrate and a defect in a substrate characteristic, for example in uniformity of a film thickness, is caused. In a substrate processing apparatus for processing a substrate, a substrate holding body for holding the substrate on its surface and a resistance heater for heating the substrate through the substrate holding body are provided. Radiation thermometers for measuring temperature of the substrate holding body, which has a correlation with a warping amount of the substrate, from its rear surface side are provided to the resistance heater. The substrate holding body is provided to be rotatable with respect to the radiation thermometers so that temperature information of the substrate holding body in a circumferential direction can be obtained.

Abstract: An object of the present invention is to provide a ceramic heater making it possible to suppress an outflow of heat to a supporting case and so on to make the temperature of its ceramic substrate uniform. The ceramic heater of the present invention is a ceramic heater wherein a heating element is arranged on a surface of a ceramic substrate or inside the ceramic substrate, the surface roughness Rmax of the side face of the ceramic substrate being from 0.1 to 200 ?m according to JIS B 0601.

Abstract: A wafer-cleaning module can remove contaminants from a semiconductor wafer prior to measurement in a metrology tool. A heating chamber and heater plate of the cleaning module can be used to heat the wafer by conduction, while a separate cooling chamber can be used to cool the wafer. The system is controlled by a processor so the heating cycle, cooling cycle and the time periods between these cycles and the measurement cycle are uniform for all wafers.

Abstract: An operating device for an electrical and/or electronic apparatus is adapted to the operating behavior of a user. The apparatus has a plurality of operating states which can be chosen or set by way of the operating device. The selection and/or setting, by the user, of the operating states is stored in a memory. A number of how often a given user input is implemented is ascertained and, for the next selection and/or setting of an operating state, that one which is implemented most frequently is suggested. An operating device for carrying out the method has a memory for storage of the implemented selections and/or settings of operating states, a counter for ascertaining the number of how often a selection and/or a setting is implemented, a calculator for ascertaining the frequency of a selection and/or setting and a comparator for ascertaining the most frequently implemented selection and/or settings.

Abstract: A chuck for a plasma processor comprises a temperature-controlled base, a thermal insulator, a flat support, and a heater. The temperature-controlled base has a temperature below the desired temperature of a workpiece. The thermal insulator is disposed over the temperature-controlled base. The flat support holds a workpiece and is disposed over the thermal insulator. A heater is embedded within the flat support and/or disposed on an underside of the flat support. The heater includes a plurality of heating elements that heat a plurality of corresponding heating zones. The power supplied and/or temperature of each heating element is controlled independently.

Abstract: A susceptor device comprises a susceptor base body, a temperature controlling section, an adhesive layer which attaches the susceptor base body and the temperature controlling section unitarily, an O-ring which is disposed near a peripheral section of the adhesive layer, a circular O-ring which is disposed on a bottom surface of the temperature controlling section, an O-ring supporting section which surrounds the temperature controlling section and compresses the O-rings on the temperature controlling section, and pushup screws which push up and fix the O-ring supporting section toward the temperature controlling section. By doing this, it is possible to protect the adhesive layer from an external environment. Also, it is possible to provide a susceptor device having a superior temperature controlling characteristics for the plate sample, operational stability, and durability.

Abstract: A heater assembly that is capable of uniformly heating a wafer in an apparatus for manufacturing a semiconductor device is provided. The heater assembly preferably includes a susceptor configured to support a substrate (wafer). A plurality of heaters can be disposed under the susceptor to heat the wafer. A support is preferably disposed below the heaters to support the heaters, and a power supply provides an electric current to operate the heaters. The support can include a heat-shielding portion that restricts heat conduction between the heaters. The heat-shielding portion preferably comprises heat-resistant material arranged in a groove formed on the support. The heat-shielding portion also preferably supports adjacent peripheral portions of the heaters. Electrical current provided to the heaters is preferably controlled such that the temperature of the heaters are operated in a range of about 390° C. to 420° C.

Abstract: An object of the present invention is to provide a ceramic heater making it possible to suppress an outflow of heat to a supporting case and so on to make the temperature of its ceramic substrate uniform. The ceramic heater of the present invention is a ceramic heater wherein a heating element is arranged on a surface of a ceramic substrate or inside the ceramic substrate, the surface roughness Rmax of the side face of the ceramic substrate being from 0.1 to 200 &mgr;m according to JIS B 0601.

Abstract: A molding heater includes a first metal plate having a recess formed on one side and a flat surface formed at the other side. A groove is formed at a lower portion of the recess and a wafer is placed on the flat surface. A hot wire is inserted into the groove. A ceramic is filled in a gap between the hot wire and the groove. A second metal plate coupled with the first metal plate fills the recess while contacting with the lower portion and lateral sides of the recess. Since the hot wire is surrounded only with a single layer of the ceramic, a resistance of the heat conduction can be minimized. Accordingly, a sufficient calorific power can be obtained through the metal plates using even a small power and a short of the hot wire due to an overload can be prevented.

Abstract: A stable and durable heat-generating element and substrate, a method of efficient and highly precise manufacture of same, and equipment utilizing same are obtained. Employing as material a silicon substrate into at least a portion of which boron or another impurity is diffused to impart conductivity, a heater portion, in which are provided one or a plurality of slits the corner portions of which are removed or are rounded, is fabricated integrally on the silicon substrate by etching processes. Simultaneously with this, a depression portion provided below to control the heating state of the heater portion is formed integrally.

Abstract: A temperature controllable vacuum chuck includes a mounting bracket, a porous plate, a heating element, and a temperature sensor. The porous plate is mounted to the mounting bracket and is configured for securing a substrate to the vacuum chuck when air is suctioned out of the vacuum chuck. The heating element is attached to the bottom of the porous plate and uniformly heats the porous plate, thereby heating any substrate mounted on the vacuum chuck and enabling control over the cure rate of fluid materials deposited on the substrate. The temperature sensor measures the temperature of the porous plate so that it can be adjusted when desired with a user controllable temperature control component.

Abstract: A heating device for manufacturing semiconductor capable of uniformly heating a wafer or other materials to be treated, and in particular a heating device in a coater-developer used for heat-hardening of resin film for photolithography and for heat-calcining of low-dielectric constant insulating film, is provided.

Abstract: Heater module, and semiconductor manufacturing equipment in which the heater module is utilized, for raising the cooling speed of a post-heating heater markedly more than conventional, and that can contribute toward bettering and improving productivity, without accompanying scaling-up of and cost increases in the semiconductor manufacturing equipment. The heater module is furnished with heater part 1a for controlled heating of a wafer placed on its top face, and block part 3a provided to be shiftable relative to said heater part, for varying heat capacity in total with heater part 1a by abutting on or separating from the reverse surface of heater part 1a. By having the heat capacity of block part 3a be 20% or more of the total heat capacity of heater part 1a and block part 3a, the heater cooling speed can be made 10° C./min or more.

Abstract: A heat-treating plate has three balls arranged on an upper surface thereof. Top ends of the balls slightly protrude from the upper surface of the heat-treating plate. A substrate is heated as placed on and supported by the balls of the heating plate such that a minute spacing called a proximity gap is formed between the lower surface of the substrate and the upper surface of the heating plate. The upper surface of the heat-treating plate has a high emissivity of 0.9 to 1.0 to heat the substrate efficiently and with high precision.

Abstract: There is provided a semiconductor wafer heat treatment apparatus and method, which can carry out a heat treatment to suppress variations in line widths within surface on a semiconductor wafer and the like, which includes: a heating plate for heating a semiconductor wafer to a predetermined temperature; a temperature measuring unit for measuring temperatures when heating the semiconductor wafer or a semiconductor wafer equivalent placed on the heating plate, at portions divided into a plurality of regions; and a controller for controlling the temperatures of the semiconductor wafer, and based on the temperature measurement result of the temperature measuring unit, the controller controls the temperature in heating the semiconductor wafer, for each of the plurality of regions. In cooling after the heating process, based on the temperature measurement result, the controller controls the temperature in cooling the semiconductor wafer, for each of the plurality of regions.

Abstract: A hot plate unit capable of uniformly cooling a hot plate within a short period of time. The hot plate unit (1) includes a hot plate (3) including a heating element (10) and a casing (2) that supports the hot plate. The hot plate and the casing define an internal space S1. Two intake ports (17) and two lower opened portions (31) are formed in the bottom wall (2a) of the casing.

Abstract: An improved heating system for heating a semiconductor wafer during fabrication in a corrosive manufacturing environment is disclosed. The system includes a novel ceramic heater made of a layered ceramic substrate that has a plurality of heating elements and temperature sensor arrangement completely and directly embedded within the ceramic substrate of the ceramic heater. The heating elements and the temperature sensor arrangement are constructed of a molybdenum and aluminum nitride composite that provides a low temperature coefficient of resistance which improves the operating efficiency of the ceramic heater. In operation, the temperature sensor arrangement transmits temperature readings to a microprocessor capable of controlling the heating elements in such a manner as to provide a constant and uniform temperature distribution along the entire surface of the semiconductor wafer.

Abstract: An object of the present invention is to provide a carbon-containing aluminum nitride sintered body wherein no short circuit is caused since its volume resistivity at a high temperature range of 200° C. or higher (for example, about 500° C.) is sufficiently high, that is, at least 1×108 &OHgr;·cm or more, and also wherein covering-up capability, a large radiant heat amount and measurement accuracy with a thermoviewer can be assured. The carbon-containing aluminum nitride sintered body of the present invention is comprising carbon whose peaks appear near 1580 cm−1 and near 1355 cm−1 in laser Raman spectral analysis in a matrix made of aluminum nitride.

Abstract: The present invention discloses a ceramic substrate for semiconductor manufacture and/or inspection conducive to decrease radiated &agr;-rays and to minimize changes in thermal conductivity as a function of time, thereby yielding a superior temperature controllability. This invention is related to a ceramic substrate for apparatuses for use in semiconductor manufacture and/or inspection, wherein the level of &agr;-rays radiated from said ceramic substrate exceeds 0.25 c/cm2·hr and is not higher than 50 c/cm2·hr.

Abstract: A heat treatment unit comprises a heat plate made of aluminum nitride which is excellent in heat conductivity and strength inside thereof. The entire circumference of the heat plate is supported by a supporting member which is excellent in thermal insulation. The heat treatment unit is equipped with a nozzle for blowing dry air against the reverse side of the heat plate. When a temperature of the heat plate is lowered, the dry air is blown from the nozzle, thereby quickly lowering the temperature of the heat plate.

Abstract: This invention has its object to provide a ceramic board which, when used as a heater, heats a silicon wafer uniformly throughout and, hence, does not damage the wafer and, when used as an electrostatic chuck, provides a sufficient chucking force.

Abstract: A ceramic heater is provided, including a ceramic substrate with a heating face and a heat generator so that the temperature on the heating face may be controlled without a temperature controlling member that is separate from the substrate. The surface of the ceramic substrate includes a heating face, a first region provided apart from the heating face and a second region provided apart from the heating face. The second region has a lower emissivity of thermal radiation than that of the first region.

Abstract: A heater assembly for an ALD or CVD reactor provides protection for an electrical conductor associated with a heating element by using a purge gas to isolate the conductor from the corrosive environment of the reactor chamber. The purge gas is introduced into a sleeve surrounding the conductor and from there is allowed to leak into the reactor chamber to be pumped out with the process gasses. This arrangement avoids the need for airtight seals at the junction of the sleeve and the heating element easing manufacturing requirements and potentially reducing component costs.

Abstract: The present invention provides a ceramic heater which makes it possible to make the distance between a semiconductor wafer and the heating surface of a ceramic substrate constant at any time, heat the semiconductor wafer at an even temperature and prevent contamination of the semiconductor wafer, and which does not cause dropping-out of a supporting pin. The ceramic heater of the present invention comprises a ceramic substrate on a surface of which or inside which a heating element is formed, wherein the ceramic heater is constituted to have a structure that an object to be heated can be held apart from a surface of said ceramic substrate and heated.

Abstract: A hot plate for a semiconductor producing/examining device, in which hot plate, when an object to be heated such as a silicon wafer is heated in a state that the object is distanced by a certain distance from the heating face, air is less likely to stagnate between the silicon wafer and the heating face and thus the object to be heated can be evenly heated. Specifically, the hot plate for a semiconductor producing/examining device includes a resistance heating element formed on a surface of a ceramic substrate or inside the ceramic substrate, wherein the glossiness of the heating face of the ceramic substrate is 1.5% or more.

Abstract: An objective of the present invention is to provide a ceramic heater having good temperature controllability, wherein a ceramic substrate is used as a base material of the heater, and a resistance heating element having superior durability such as superior oxidization resistance is set up. The ceramic heater of the present invention is characterized in that a resistance heating element composed of one circuit or more circuits is arranged on a ceramic substrate and an insulating covering is deposited on the resistance heating element.

Abstract: Ceramic susceptor whose wafer-retaining face has superior isothermal properties, and that is suited to utilization in apparatuses for manufacturing semiconductors and in liquid-crystal manufacturing apparatuses. In plate-shaped sintered ceramic body 1, resistive heating element 2 is formed. Fluctuation in pullback length L between sintered ceramic body outer-peripheral edge 1a and resistive heating element substantive-domain outer-peripheral edge 2a is within ±0.8%, while isothermal rating of the entire surface of the wafer-retaining face is ±1.0% or less. Preferable is a superior isothermal rating of ±0.5% or less that can be achieved by bringing the fluctuation in pullback length L to within ±0.5%.

Abstract: A system and method are described for modifying an exposure image in a radiation sensitive layer by treating the exposure image with a heterogeneous and non-uniform post exposure thermal treatment. The treatment may comprise providing different portions of the exposure feature, such as different exposure features or critical dimensions, with different thermal fluxes from a thermal modification system, such as a post exposure bake oven or hot plate configured to provide different thermal fluxes. The thermal modification system may comprise one or more adjustable spacers to adjust a radiant energy flux from a thermal energy source to the radiation sensitive layer by adjusting a separation distance between the source and the layer.

Abstract: Ceramic susceptor having a processed-object retaining face—and semiconductor as well as liquid-crystal manufacturing apparatuses in which the susceptor is installed—in which temperature uniformity in the surface of an object being processed on the susceptor is enhanced. Forming a resistive heating element in the susceptor surface on other than its processed-object retaining side, or on an internal surface of the susceptor, and forming a lead circuit for supplying electricity to the resistive heating elements in a surface separate from the surface on which the resistive heating element is formed, allows the temperature uniformity of the susceptor to be enhanced and enables uniformization of the temperature distribution in the processed-object retaining face.

Abstract: Disclosed are an apparatus and a method for bonding electronic components, a circuit board, and an electronic component mounting apparatus, whereby various kinds of circuit boards can be manufactured, each by a small amount, with high productivity as compared with the conventional art. There are provided a stage member and a heating device, so that a circuit board is heated by the heating device while held in contact with the stage member, which stage member has a size almost equal to that of one circuit board. Generation of losses can be reduced for compact circuit boards, and heating can be performed individually, correspondingly, for each kind of circuit board. Manufacturing various kinds of circuit boards, each by a small amount, with high productivity as compared with the conventional art is enabled accordingly.

Abstract: A ceramic heater capable of reducing temperature uniformity at the periphery of through holes such as insertion holes and vacuum suction holes is provided, which protects wafer against thermal shocks and has improved controllability for temperature control parts such as thermocouples and temperature fuse. Further, a ceramic heater capable of uniform resin curing is provided. A heat generation body is disposed on the surface or inside of a ceramic substrate. Further, corners for the insertion holes, the recesses and the vacuum suction holes of the ceramic substrate are chamfered.

Abstract: An apparatus for heating a substrate of a semiconductor device includes a hot plate, on which a semiconductor substrate is placed, and a heater for heating the hot plate. The hot plate is preferably a composite plate including a plurality of plates having different thermal conductivities from each other. For example, a first plate adjacent to the heater can be made of aluminum, which has a relatively high thermal conductivity. A second plate, laminated on top of the first plate, can be made of titanium or stainless steel, which both have a thermal conductivity lower than aluminum. A composite hot plate as disclosed herein is better able to maintain a constant temperature and a uniform temperature distribution in order to more uniformly heat a substrate and to reduce an amount of energy required for the heating process. In addition, the reliability and productivity of the semiconductor device manufactured by the apparatus can be improved.

Abstract: Affords holders for semiconductor or liquid-crystal manufacturing devices—and semiconductor manufacturing devices in which the holders are installed—in which temperature uniformity in the processed-object retaining face of their resistive-heating-element containing ceramic susceptor is enhanced. By arranging a metal plate on a resistive-heating-element containing ceramic susceptor opposite its processed-object retaining side, the surface temperature of a semiconductor wafer or LCD glass being retained on the susceptor can be made uniform. Although simply setting the metal sheet on the ceramic susceptor is efficacious, fastening it by bonding, screws, snug-fitting, or vacuum adhesion further enhances the efficacy.

Abstract: The present invention is directed to a semiconductor thermal processing system and an apparatus for thermally cooling a semiconductor substrate. According to one aspect of the present invention, a semiconductor thermal processing system and associated apparatus and method are disclosed which provides a segmented cold plate situated within a process chamber, wherein a plurality of segments of the cold plate are operable to radially translate between an engaged position and a disengaged position, wherein a substrate holder may pass between the plurality of segments when the segments are in the disengaged position. According to another aspect, an elevator is operable to linearly translate a substrate residing on a substrate holder between a heating position proximate to a heater assembly and a cooling position proximate to the segmented cold plate.

Abstract: An apparatus and method for processing a microelectronic workpiece at an elevated temperature. In one embodiment, the apparatus includes a workpiece support positioned to engage and support the microelectronic workpiece during operation. The apparatus can further include a heat source having a solid engaging surface positioned to engage a surface of the microelectronic workpiece with at least one of the heat source and the workpiece support being movable relative to the other between a first position with the microelectronic workpiece contacting the engaging surface of the heat source and a second position with the microelectronic workpiece spaced apart from the engaging surface. The heat source is sized to transfer heat to the microelectronic workpiece at a rate sufficient to thermally process a selected material of the microelectronic workpiece when the microelectronic workpiece is engaged with the heat source.

Abstract: A substrate processing apparatus includes a first holder made of silicon carbide or silicon and a second holder made of quartz. Each of the first and the second holder is of a ring shape and the second ring shaped holder is mounted on the first holder. The second holder is used to mount a substrate thereon while the substrate is being processed.

Abstract: A bake plate is integrally formed from a copper disk whose lower surface defines a desired heater element channel pattern that is filled with electrically conductive resistive material. Copper contamination is prevented by coating the structure. The channel pattern and fill material may be tailored to optimize thermal uniformity across the bake plate surface, and to produce a bake plate that may be mass produced with substantially uniform and repeatable thermal characteristics.

Abstract: An object of the present invention is to provide a ceramic heater making it possible to heat the whole of a subject to be heated uniformly. The ceramic heater of the present invention is a ceramic heater wherein a resistance heating element is arranged on a surface of a disc-shaped ceramic substrate or inside the substrate, characterized in that the resistance heating element is composed of a mixture of a resistance heating element having a concentric or spiral pattern and a resistance heating element having a pattern of repeated winding lines.

Abstract: An object of the present invention is to provide a ceramic heater making it possible to make the temperature of a face for heating a silicon wafer even and prevent damage of the silicon wafer. The ceramic heater of the present invention is a ceramic heater comprising resistance heating elements formed on a surface of a ceramic substrate in a disc form or inside the ceramic substrate, wherein the resistance heating elements composed of two or more circuits being divided in the circumferential direction are arranged in the outermost periphery of the ceramic substrate and further the resistance heating element composed of a different circuit is formed in the inner portion of the resistance heating elements being arranged in the peripheral portion.

Abstract: To provide a wafer heating apparatus that can measure a surface temperature of a wafer accurately and responsively. A front surface of a ceramic plate 2 serves as a mounting surface on which a wafer is placed, and a rear surface or an inner portion of the ceramic plate 2 is formed with a resistance heating element 5. A recess 9 is formed in the rear surface of the ceramic plate 2. A temperature measuring member formed of a temperature sensor 8a and leads 8 is inserted in the recess 9 so as to be held by filling 17. In the wafer heating apparatus, a length along the leads from the front of the protective tube to a point where the leads are exposed from the filling is set to 5 to 30 times an outer diameter of the protective tube.

Abstract: A system, method and apparatus are described for improving critical dimension uniformity in baked substrates. The system, method and apparatus provide for varying the distance between a substrate to be baked and the surface of a hot plate such that an approximately uniform temperature is obtained in the substrate during baking. In one embodiment, the substrate is positioned on a hot plate having a recess generally centered on its top side. The differences in distance between the edges of the substrates contacting the hot plate and the distance between the center region of the substrate and the bottom of the recess enable a generally uniform temperature to be obtained in the substrate.

Abstract: A hot plate unit (1) having a reduced heater temperature rise time and not generating dusts. The hot plate unit comprises a casing (2) having an opening portion; a heater (3) arranged on the opening portion and including a plate-shaped member (9) made from ceramics and a heat generating element (10) arranged on the plate-shaped member; and a radiant heat reflecting member (4) interposed between the casing and the heater.

Abstract: A heating apparatus includes a central hot plate for heating the center portion of a substrate, a plurality of segment hot plates for heating the peripheral portion of the substrate, a hot plate support member supporting the central hot plate and the segment hot plates, support pins for supporting the substrate so as to face the central hot plate and the segment hot plates in a close proximity without being in contact with the central hot plate and the segment hot plates, and a power supply for supplying electricity to the central hot plate and the segment hot plates.

Abstract: In a ceramic heater having a plate-like body made of a ceramic, heating element in one main face of the plate like body, and an electric supply portion to be electrically connected with the heating element, it has been a problem that the temperature is uneven if bent portions are formed in heat generating patterns. The ceramic heater simultaneously satisfying the following: 0.15≦S≦0.85, 0.3≦P≦6.71×S2+1.52, and 0.3≦G≦6.71×(1−S)2+1.55, in which the reference character S1 denotes the surface area of the heating element in optional 10 mm square region of the effective heat generation area having the heating element therein; the surface ratio S denotes S=S1/100 mm2, the reference character P denotes the width of the heating element: and the reference character G denotes the gap between the heating element.