JP5381878B2 - Wafer heating heater unit and semiconductor manufacturing apparatus equipped with the same - Google Patents

Description

  The present invention relates to a wafer heating heater unit used in a semiconductor manufacturing apparatus. In particular, the present invention relates to a heater unit for heating a wafer that is excellent in rapid temperature rise and heat uniformity and excellent in reliability.

  In a semiconductor manufacturing process, various processes such as a film forming process and an etching process are performed on a semiconductor wafer which is an object to be processed. When it is necessary to heat the wafer, the wafer is placed on the wafer heating heater unit and subjected to a predetermined heat treatment. Examples thereof include a coater developer used for wafer photolithography, a wafer prober for semiconductor inspection, and a CVD apparatus for film formation.

  Among these, in the photolithography process for forming a resist film on the wafer, the wafer is washed, heated, dried, cooled, and then coated with a resist film on the wafer surface, and the wafer is applied to the heater unit in the photolithography processing apparatus. After mounting and drying, processing such as exposure and development is performed.

  Regarding the processing of wafers in these semiconductor manufacturing apparatuses, it is required to finish the processing in as short a time as possible in order to improve the throughput. Also, when the wafer is heated, the wafer is mounted on the heater unit, subjected to heat treatment, and then removed from the heater unit for transfer to the next process. Thermal properties are required. In addition, when the temperature condition of the heater is changed, for example, when the temperature is raised or lowered, it is necessary to quickly set the heater temperature. In addition, reliability is required for the heater to be used.

  For example, Patent Document 1 discloses a heating body for heating a wafer, which includes a heater provided with a heating element and a soaking plate via a heat insulating layer. In Patent Document 1, when the heating element is a metal foil, the metal foil is sandwiched between heat-resistant resins, for example, and the resin sandwiched between the metal foils is fixed between the heater substrate and the heat equalizing plate via a heat insulating layer. It is disclosed.

  As in Patent Document 1, when a metal foil heating element is sandwiched between heat-resistant resins and sandwiched between a heater substrate and a soaking plate via a heat insulating layer, the resin sandwiched between the metal foils is a portion where the metal foil is present. Then, the thickness is reduced as compared with a portion where no metal foil is present. For this reason, in the portion where the metal foil does not exist, a gap is likely to be generated between the heater substrate or the soaking plate, and the heat generated in the metal foil by this gap is uniformly conducted to the heater substrate and the soaking plate. In some cases, the soaking property may be impaired.

  In addition, when the metal foil generates heat, both the metal foil and the heat insulation layer rise in temperature. However, when the metal foil and the heat insulation layer have different thermal expansion coefficients, the metal foil and the heat insulation layer have different amounts of thermal expansion. When the heat insulating layer is bonded, the heating body is deformed due to the difference in thermal expansion amount, and warpage or the like occurs. For this reason, the adhesion of the heater substrate, the heating element, and the soaking plate is impaired, so that the soaking property is greatly deteriorated, and when these are mechanically fixed, the fixing portion may be damaged. It was.

  Furthermore, even when the cooling module is in contact with the soaking plate, there is a problem that if there is a gap between the cooling module and the soaking plate, the cooling of the gap becomes slow and temperature unevenness is likely to occur. To do.

JP 2008-118080 A

  The present invention has been made to solve the above problems. That is, an object of the present invention is to provide a wafer heating heater unit excellent in heat uniformity and reliability and a semiconductor manufacturing apparatus equipped with the same.

The heater unit for heating a wafer according to the present invention has a mounting table having a wafer mounting surface, a resistance heating unit on the surface opposite to the wafer mounting surface, and supports the mounting table and the resistance heating unit. The resistance heating unit is composed of a heating element and an insulating layer between the heating element and the mounting table, and the inclusion of the same material as the heating element exists in a portion where the pattern of the heating element does not exist In addition, an insulator is provided between the heating element and the inclusion, and the heating element and the inclusion have substantially the same thickness .

  Preferably, the support plate is a conductor, and an insulating layer exists between the resistance heating unit and the support plate.

  A semiconductor manufacturing apparatus equipped with such a wafer heating heater unit can be excellent in heat uniformity, reliability, and throughput.

  ADVANTAGE OF THE INVENTION According to this invention, the heater unit for wafer heating excellent in soaking | uniform-heating property and reliability can be provided.

The schematic diagram of the cross-sectional structure of the heater unit for wafer heating of this invention is shown.

  Referring to FIG. 1, the heater unit for heating a wafer according to the present invention has a mounting table 1 having a wafer mounting surface 10 and a resistance heating unit 2 on the surface opposite to the wafer mounting surface, The resistance heating unit 2 includes a heating element 21 and an insulating layer 22 between the heating element and the mounting table 1, and there is no pattern of the heating element 21. Inclusions 23 exist in the portion.

  The presence of the inclusions 23 in the portion where the pattern of the heating element does not exist eliminates the thickness distribution due to the presence or absence of the heating element, and the adhesion between the mounting table, the resistance heating unit, and the support hill increases. Therefore, the thermal uniformity of the wafer mounting surface can be improved.

  The heating element and the inclusion may be the same material. In this case, the punching pattern generated when the heating element pattern is formed can be used as an inclusion, which is economical. It is necessary to insert an insulator between the heating element and the inclusion.

  Alternatively, the heating element and the inclusion may have substantially the same thickness, and the inclusion may be an insulator. In this case, since the heating element is fitted into the insulator obtained by removing the heating pattern from the insulator, the manufacturing process is easy and the productivity can be improved.

  The thickness of the heating element and the thickness of the inclusion are preferably the same or the heating element is preferably about 20 μm thick. If the thickness of the heating element is increased to more than 50 μm from the thickness of the inclusions, it is not preferable because the above-mentioned heat uniformity is likely to be adversely affected. The most preferred range is from equivalent to about 10 μm.

  When the support plate is a conductor, it is necessary to insert an insulating layer between the resistance heating unit and the support plate.

  In the present invention, two or more heating elements can be laminated.

  The mounting table and the support plate of the present invention are preferably made of a material having high thermal conductivity from the viewpoint of heat uniformity. Examples of the material having high thermal conductivity include copper, aluminum, silicon carbide, aluminum nitride, and composite materials containing these. Examples of the composite material include a composite of silicon and silicon carbide (Si—SiC) and a composite of aluminum and silicon carbide (Al—SiC).

  In the combination of the mounting table and the support plate, at least one of them is preferably made of a highly rigid material. The material having high rigidity is a composite containing aluminum nitride, silicon carbide, and ceramics thereof.

  If both the mounting table and the support plate are made of a material with relatively low rigidity, such as aluminum, deformation is likely to occur due to the heat cycle of the resistance heating unit or the like, and the cooling module and the support plate or resistance heating unit Since the adhesiveness with the mounting table changes and the shape of the mounting surface changes, characteristics such as heat uniformity deteriorate, which is not preferable. Further, in order to improve the thermal uniformity of the wafer to be mounted, it is preferable that the thermal conductivity of the mounting table is relatively high and the rigidity (Young's modulus) of the support plate is relatively high.

  The heating element is preferably a metal foil such as stainless steel, nickel chromium alloy, inconel, molybdenum, tungsten. Among these, stainless steel is most preferable in terms of productivity and cost.

  The insulating layer is preferably made of polyimide, mica, Teflon (registered trademark), or the like. Of these, polyimide is most preferred because it can be used with a low thermal resistance and a small thickness.

  The inclusion is preferably made of the same material as the heating element, or is polyimide or Teflon (registered trademark). When the inclusion and the heating element are made of the same material, it is necessary to insert a polyimide or Teflon (registered trademark) insulator between the inclusion and the heating element to insulate the inclusion from the heating element.

  The mounting table and the support plate are preferably mechanically coupled with the resistance heating unit interposed therebetween. When the material of the mounting table and the support hill are different, or when the cooling module is installed on the support plate side, when a normal temperature wafer is mounted on the mounting table, a temperature difference or a thermal expansion difference occurs, which is affected by these effects. This is to make it difficult. Examples of the mechanical coupling method include screwing and fixing with a spring, but screwing is most preferable from the viewpoint of stability.

  It is preferable to install a support (not shown) for supporting the wafer on the mounting surface. The support forms a minute space between the wafer and the mounting surface to prevent particles from adhering to the backside of the wafer, and improves the temperature distribution (thermal uniformity) of the wafer by forming a minute space. Can be made. The support is preferably installed so that the distance between the wafer and the mounting surface is about 10 to 300 μm.

  The heater unit for heating a wafer according to the present invention preferably includes a movable cooling module below the support plate. For example, the cooling rate can be improved by keeping the cooling module away from the support plate during heating and contacting the support plate during cooling. The cooling module includes a method in which a groove is formed in a plate-like body such as copper or aluminum, a metal pipe is attached to the groove, and water or an organic refrigerant is allowed to flow through the pipe.

  Moreover, a flow path can be formed in one or both of two metal plates, and it can join by brazing or welding to make a cooling module. In addition, the cooling module is not formed with a flow path for flowing the refrigerant, but is brought into contact with a container such as a chamber when the cooling module is separated from the support plate, so that the cooling module is cooled by flowing the refrigerant through the container. It may be a structure.

  Among the above, it is preferable not to form a refrigerant flow path in the cooling module itself because the temperature distribution of the cooling module is less likely to affect the wafer heating heater unit. When the refrigerant flow path is formed in the cooling module, the temperature of the refrigerant introduction portion out is low, but the temperature of the cooling module increases because the temperature of the refrigerant rises near the refrigerant outlet. Occurs. This is because the temperature distribution of the cooling module may affect the temperature distribution of the wafer mounting surface of the wafer heating heater unit.

  A plate of aluminum nitride sintered body (AlN), copper (Cu), and aluminum (Al) was prepared as a mounting table. These diameters were 320 mm and the thickness was 5 mm.

The aluminum nitride sintered body was prepared by adding 0.5 parts by weight of yttrium oxide (Y ₂ O ₃ ) to 99.5 parts by weight of aluminum nitride (AlN) powder, adding an acrylic binder and an organic solvent, and adding 24 parts by a ball mill. Mixing for a time, an AlN slurry was prepared. The slurry was produced by spray-drying granules, press-molded, degreased in a nitrogen atmosphere at 700 ° C., and sintered in a nitrogen atmosphere at 1850 ° C. This AlN sintered body was machined to have a diameter of 320 mm and a thickness of 5 mm. The surface roughness of the upper and lower surfaces of this AlN sintered body was Ra 0.8 μm, and the flatness was 50 μm.

  A 50 μm thick stainless steel foil (SUS) or nickel chrome alloy (NiCr) was etched into a predetermined circuit pattern to obtain a heating element. Further, polyimide having a thickness of 25 μm, mica having a thickness of 200 μm, and Teflon (registered trademark) having a thickness of 200 μm were prepared and used as an insulating layer. Moreover, stainless steel foil, polyimide, and nickel chrome alloy were prepared as inclusions. In the case of stainless steel foil and nickel chrome alloy, use the extraction pattern of the circuit pattern of the heating element, and insert a polyimide sheet with the heating element pattern and the area of the inclusion of the extraction pattern between the heating element. Insulated. When insulation is made of Teflon (registered trademark), a Teflon (registered trademark) resin is embedded between the heating element and the inclusion and hardened, and then processed to have the same thickness as the heating element. When the inclusion was polyimide, it was made to be in the extraction pattern of the circuit pattern of the heating element by etching. These heating elements, inclusions, and insulating layers were combined to form a resistance heating unit.

  As the support plate, Si—SiC, Al—SiC, and an aluminum nitride sintered body were prepared. These diameters were 320 mm and the thickness was 5 mm.

  The mounting table, the resistance heating unit and the support plate are fixed with screws, a power supply electrode is mounted on the heating element, and a temperature measuring resistance element for temperature control is mounted on the opposite side of the mounting table on the wafer mounting surface. A heater unit for heating the wafer was obtained. When the support plate is Si—SiC and Al—SiC, these are conductors, and therefore, between the support plate and the resistance heating unit, polyimide having a thickness of 25 μm or Teflon (registered trademark) having a thickness of 200 μm, Mica having a thickness of 200 μm was inserted as an insulating layer.

  The heat uniformity at 130 ° C. of these heater units for heating the wafer was measured. In the measurement, the temperature is raised to 130 ° C. and kept stable for 15 minutes, and then a wafer thermometer having a diameter of 300 mm capable of measuring 65 points is mounted on the mounting surface by the wafer transfer device, and then mounted. The difference between the maximum temperature and the minimum temperature at 65 points after 2 seconds was regarded as soaking.

  Moreover, the time until cooling from 130 ° C. to 80 ° C. was measured. In order to increase the cooling speed, a cooling pipe is embedded in the bottom of the chamber, cooling water cooled by a chiller is poured, and an aluminum plate having a thickness of 5 mm and a diameter of 320 mm is used as a movable cooling module. Adhered.

  Table 1 shows the measurement results of the materials such as the mounting table, the heating element, and the support plate, and the soaking property and cooling time.

  In any of the heater units for heating the wafer, on the wafer mounting surface, one support (proximity) is provided at the center of the wafer mounting surface, eight at the outer peripheral portion of the wafer mounting surface, and the middle. Four pieces were arranged almost uniformly in the area so that the distance between the wafer mounting surface and the wafer back surface was 0.1 mm.

  It can be seen that, as in the present invention, inclusions exist between the patterns of the heating elements and the inclusions have good thermal conductivity, so that both heat uniformity and cooling performance are improved.

  According to the present invention, it is possible to provide a wafer heating heater unit having high reliability and excellent heat uniformity, and a semiconductor manufacturing apparatus equipped with the same.

DESCRIPTION OF SYMBOLS 1 Mounting stand 2 Resistance heating unit 3 Support plate 10 Wafer mounting surface 21 Heat generating body 22 Insulating layer 23 Inclusion

Claims (3)

The resistance heating unit, comprising: a mounting table having a wafer mounting surface; a resistance heating unit on a surface opposite to the wafer mounting surface; and a support plate supporting the resistance heating unit. Is composed of a heating element and an insulating layer between the heating element and the mounting table, the inclusion of the same material as the heating element is present in a portion where the pattern of the heating element does not exist, and the heating element and the inclusion A heater unit for heating a wafer , comprising an insulator in between , wherein the heating element and the inclusion have substantially the same thickness . The heater unit for heating a wafer according to claim 1 , wherein the support plate is a conductor, and an insulating layer is present between the resistance heating unit and the support plate. A semiconductor manufacturing apparatus comprising the wafer heating heater unit according to claim 1 .

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