Abstract:
A lamp unit that is useful in a photoirradiating-type heating device that does not contaminate the processing chamber of a photoirradiating-type heating device, that permits the lamp to be reliably cooled, that permits the lamp to be reliably turned on, that inhibits the decline in the reflectance on the inner surface of an optical guide, and that permits attenuation of irradiation intensity to be inhibited. The lamp unit has a metal sleeve with an aperture at one end and a single ended lamp mounted so that sealed part of the lamp would be situated on the inside of the sleeve on the aperture side of sleeve, a coupling member having a contact support unit that makes contact with the outer surface of a sealed part of the lamp by elastic force as well as a contact fastening unit that makes contact with the inner surface of the sleeve after the contact support unit and that also fastens a single ended lamp to the sleeve.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to a lamp unit utilized in a photoirradiating-type heating device that carries out heating treatment utilizing light for growing, diffusing and annealing semiconductor wafers. More particularly, the invention is directed to lamp unit that is useful in a photoirradiating-type heating device that does not contaminate the processing chamber of the device, that permits the lamp to be reliably cooled, that permits the lamp to be reliably turned on, that inhibits the decline in the reflectance on the inner surface of an optical guide, and that permits attenuation of irradiation intensity to be inhibited. The lamp unit has a metal sleeve with an aperture at one end and a single ended lamp mounted so that sealed part of the lamp would be situated on the inside of the sleeve on the aperture side of sleeve, a coupling member having contact support unit that makes contact with the outer surface of a sealed part of the lamp by elastic force as well as a contact fastening unit that makes contact with the inner surface of the sleeve after the contact support unit and that also fastens a single ended lamp to the sleeve. 
     2. Description of the Related Art 
     Photoirradiating type heating devices have been used over a broad range of procedures in semiconductor production including growth, diffusion and annealing. Semiconductor wafers are subjected to uniform heating processing at high temperatures to rapidly heat wafers through photoirradiation in all processing, and temperature elevation to levels exceeding 1000 degrees Celsius can take anywhere from a dozen seconds to several dozen seconds. After holding at a fixed temperature, the wafer is rapidly cooled by halting photoirradiation. 
     FIG. 1 shows a conventional photoirradiating-type heating device as is known from U.S. Pat. No. 5,155,336. In the figure, a wafer  3  is shown supported on a wafer suppport stage  2  for heat processing within a processing chamber  1  partitioned by a quartz window  8 . The quartz window  8  is used when the ambient atmospheres of the wafer  3  and the lamp  4  differ. The lamp  4  is a single ended lamp in which a sealed part  41  is mounted only at one edge of the lamp  4 . As shown in FIG. 1, a plurality of lamps are disposed over the wafer  3 . The sealed part  41  of each lamp  4  is disposed within cylindrical metal sleeve  5 . The lamp  4  is fastened to the sleeve  5  by an adhesive and the sleeve  5  is mated within a cylindrical optical guide  7  composed of a metal-plated stainless steel that is fastened to a wall member  6 . The space formed by the wall  6  and the optical guide  7  forms a cooling chamber  9  in which a cooling liquid is flowed. 
     As shown in FIG. 2, a front optical guide  71  is mounted in front of the aperture of the optical guide  7  to efficiently reflect light from the lamp  4  off of wafer  3 , but the optical guide  7  may be extended to complete a structure that doubles as the front optical guide  71 . When power is applied to the lamp  4 , the filament within the lamp  4  fires and the light that is irradiated directly upon the wafer  3  is also reflected off the inside reflecting surface of front of the optical guide  71 , thereby heating the wafer  3 . A cooling liquid is flowed within the cooling chamber  9  so that the temperature of the sealed part  41  of the lamp  4 , the optical guide  7  and the sleeve  5  is not raised excessively by the radiant energy from the lamp  4 . The sealed part  41  of the lamp  4  is positioned within at one end of the cylindrical metal sleeve  5 . The sealed part  41  is fastened to the sleeve  5  by an inorganic, inelastic adhesive S. In this way, a lamp unit is constructed in which lamp  4  and sleeve  5  are integrated by adhesive S. The sleeve  5  is constructed so that the sides contact cylindrical optical guide  7 . Adhesive S fastens lamp  4  and also vents heat from sealed part  41  accompanying lighting of lamp  4  as well as heat from the luminous tube after sealed part  41  to sleeve  5  via adhesive S. Heat transmitted to sleeve  5  is conveyed to optical guide  7  which is cooled by the cooling liquid circulating about the exterior of optical guide  7  to ultimately cool lamp  4 . 
     The conventional device, however, has several disadvantages. For example, adhesive S packed in sleeve  5  is exposed to processing chamber  1  at the bottom of optical guide  7 . When stress is repeatedly applied to inelastic adhesive S through turning lamp  4  on/off, part of adhesive S peels off and falls into processing chamber  1  to contaminate it. In addition, when packing adhesive S within slender sleeve  5 , it is difficult to completely pack adhesive S within sleeve  5 , and thereby leaving gaps K where adhesive S was not packed within sleeve  5 . In this case, efficient venting of heat from sealed part  41  via adhesive S is impossible due to such gaps K. Adequate cooling cannot be carried out and the cooling effect is attenuated. Furthermore, if adhesive S packed within slender sleeve  5  is inadequately dried because of the difficulty of complete drying, lead wires  10  are shorted by moisture contained within adhesive S when lamp  4  is turned on and lamp  4  becomes inoperative. 
     In addition, adhesive S is heated when lamp  4  is turned on and the moisture contained within adhesive S is released. It then contaminates the inner surface N (the region denoted by the broken lines for convenience) of front optical guide  71  on the aperture side of optical guide  7 , thereby lowering the reflectance on the inner surface of front optical guide  71 , and precluding efficient wafer heating. When lamp  4  is lit, the temperature of adhesive S rises, thereby releasing moisture contained in adhesive S. This causes devitrification of the luminous tube of lamp  4  which lowers the irradiation intensity. 
     SUMMARY OF THE INVENTION 
     Accordingly, an object of the invention is to overcome the disadvantages of the prior art in devising a lamp unit that is useful in a photoirradiating type heating device that does not contaminate the processing chamber of a photoirradiating type heating device, that permits the lamp to be reliably cooled, that permits the lamp to be reliably turned on, that inhibits the decline in the reflectance on the inner surface of an optical guide, and that permits attenuation of irradiation intensity to be inhibited. 
     The lamp unit includes a cylindrical metal sleeve having an aperture at one end and made of SUS steel and a single ended lamp mounted so that a sealed part of the lamp can be situated on the inside of the sleeve. The lamp is fastened to the sleeve by a coupling member attached to the sleeve and which supports the sealed part of the lamp. The coupling member is composed of a single piece of aluminum that is bent so as to form a contact support unit and a contact fastening unit. Due to the bending, elastic force is generated in the contact support units and the contact fastening units. 
     The contact support units contact the outer surface of the sealed part of the lamp to enable the coupling member to pinch and support the sealed part by elastic force. Accordingly, the contact fastening units that contacts the inner surface of the sleeve is formed after the contact support unit. The contact fastening unit makes contact with the inner surface of the sleeve utilizing the force that opens outwardly through the elastic stress of the coupling member itself. The contact fastening unit fits against a projection to thereby fasten the lamp to the sleeve. 
     In this way, the various problems associated with using an adhesive are obviated since the lamp is mechanically fastened without using an adhesive. For example, the interior of the processing chamber is not contaminated by peeling of adhesive itself and the shorting of lead lines that supply power to lamp do not occur due to the effects of moisture contained in the adhesive. Moreover, the decline in the reflectance due to the contamination by moisture on the inner surface of the optical guide or front optical guide and devitrification of the luminous tube do not occur. And, the irradiation intensity is not attenuated since adhesive is not used. 
     Furthermore, since the sleeve is mated to the optical guide on its outer circumferential surface, heat from the lamp is transmitted to the coupling member via the sealed part. The heat transmitted to coupling member is subsequently transmitted to the sleeve. The heat transmitted to sleeve is subsequently transmitted to the optical guide. The heat transmitted to the optical guide is subsequently transferred to the cooling liquid circulating on the outer surface. Consequently, a series of heat-conduction passages are formed that reliably cool the lamp. 
     The coupling member need not be composed exclusively from metal, and pre-molded plastic having a high heat resistance or a ceramic material coated on the surface with a heat-transmitting material may be used. In short, any unit that reliably fastens the lamp to the sleeve and which transmits heat from the lamp to the sleeve may be used. A heat-transfer sleeve that does not impair the support between the sealed part and the contact support unit of the coupling member and which raises the heat-transfer characteristics may be interposed to improve the contact between these units. 
     The section of the coupling member opposes a luminous unit of the lamp and forms a reflection surface. The reflectance on the surface of reflection surface can be raised by applying a metal coating. As a result, the light radiated from the lamp and reflected from the inner surface of the front optical guide and then returned toward the lamp can be efficiently reflected in the direction of the aperture of the front optical guide to permit efficient wafer heating. 
     In a second embodiment, the lamp unit includes a coupling member comprising a contact fastening unit composed of a block of aluminum and a flat contact support unit composed of copper. When the contact support unit contacts the sealed part, part of the contact support unit forms a projection which mates with a depression of the sealed part to reliably support the lamp. On the other hand, the external shape of the contact fastening unit is cylindrical, having an outer diameter which is roughly equal to the inner diameter of the sleeve. The contact fastening unit is pushed and press-fit to the forward aperture of the sleeve with the outer circumference of the contact fastening unit mated and fastened to the inner surface of the sleeve. 
     The contact support unit comprises a set of metal plates, one end of which is bent in advance to provide elasticity to the projection. An insertion aperture of the lamp sealed part contact fastening unit is fitted in this state. When one end of the contact support unit penetrates the contact fastening unit, the other edge that penetrates and jumps out is bent. The sealed part of the lamp is press-fit in the gap formed with the opposing contact support unit, and both sides of the sealed part are pinched and supported by the contact fastening unit. The surface of the contact support unit that faces the luminous unit of the lamp then forms the reflection surface. 
     In a third embodiment, the lamp unit includes a coupling member having a contact support unit and the contact fastening unit as separate units. The contact support unit comprises a set of metal plates that are bent in prescribed shape, to provide elasticity. The plates contact both sides of the sealed part to pinch and support it. While the lamp is supported by the contact support unit, it is fitted so as to contact the inner surface of the contact fastening unit. Accordingly, contact support unit is firmly fastened to the contact fastening unit by the outward expansive elastic force of the contact support unit and the sealed part is pinched and supported by the contact support unit. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a side view of a photoirradiating-type heating device of a conventional lamp unit; 
     FIG. 2 is a side view of a conventional lamp unit; 
     FIG. 3 is a side view of the lamp unit in accordance to the present invention; 
     FIG. 4 shows the coupling member of the lamp unit in FIG. 3; 
     FIG. 5 is a front view of lamp unit and optical guide of FIG. 3 viewed from the apex of the lamp; 
     FIG. 6 is a side view of a second embodiment of the lamp unit; 
     FIG. 7 is a perspective view of the contact support unit and the contact fastening unit of the lamp unit of FIG. 5; 
     FIG. 8 is a side view of a third embodiment of the lamp unit; 
     FIG. 9 is perspective view of the contact fastening unit of the lamp unit of FIG. 5; 
     FIG. 10 is a perspective view of the contact fastening unit of the lamp unit of FIG. 8; and 
     FIG. 11 is a side view of a fourth embodiment of the lamp unit. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIG. 3, the lamp unit R comprises a cylindrical metal sleeve  5  made of SUS steel and a single ended lamp  4  mounted so that sealed part  41  of the lamp would be situated on the inside of sleeve  5  having an aperture at one end. Lamp  4  is fastened to sleeve  5  by coupling member H that is connected to sleeve  5  and that supports sealed part  41  of lamp  4 . Coupling member H is made of a single piece of aluminum that is bent at the sections denoted by dotted lines so as to form contact support unit H 1  and contact fastening unit H 2 , as shown in FIG.  4 . Elastic force is generated in contact support unit H 1  and contact fastening unit H 2  by such bending. Sealed part  41  of lamp  4  fits in section A in the diagram. 
     Contact support unit H 1  contacts the outer surface of sealed part  41  of lamp  4  on both sides to enable coupling member H to pinch and support sealed part  41  by elastic force. Then, contact fastening unit H 2  that contacts the inner surface of sleeve  5  is formed after contact support unit H 1 . Contact fastening unit H 2  makes contact with the inner surface of sleeve  5  utilizing the force that opens outwardly through the elastic stress of coupling member H itself. It fits against projection  51  to fasten lamp  4  to sleeve  5 . In this way, the various issues associated with adhesive which had posed problems in the past are solved since lamp  4  is fastened without using adhesive. 
     Concretely, the interior of the processing chamber is not contaminated by peeling of adhesive itself. The shorting of lead lines that supply power to lamp  4  due to the effects of moisture contained in adhesive does not take place. The decline in the reflectance due to contamination by moisture on the inner surface of optical guide  7  or front optical guide  71  does not take place. Devitrification of the luminous tube does not take place and the irradiation intensity is not attenuated since adhesive is not used. Furthermore, sealed part  41  of lamp  4  is connected to sleeve  5  by coupling member H, as mentioned above. Since sleeve  5  is mated to optical guide  7  on its outer circumferential surface, heat from lamp  4  is transferred or transmitted to coupling member H via sealed part  41 . The heat transmitted to coupling member H is then transmitted to sleeve  5 . The heat transmitted to sleeve  5  is then transmitted to optical guide  7 . The heat transmitted to optical guide  7  is then transferred to the cooling liquid circulating on the outer surface. Consequently, a series of heat-conduction passages are formed that reliably cool lamp  4 . 
     Coupling member H need not be composed exclusively from metal. Pre-molded plastic having high heat resistance or ceramic material coated on the surface with heat-transmitting material may be used. In short, any unit that reliably fastens lamp  4  to sleeve  5  that transmits heat from lamp  4  to metal sleeve  5  may be used. A heat-transfer sleeve that does not impair the support between sealed part  41  and contact support unit H 1  of coupling member H and which raises the heat-transfer characteristics may be interposed to improve the contact between these units. 
     FIG. 5 is a front view of the lamp unit R and the optical guide  7  of FIG. 3 viewed from the apex of the lamp. The section of coupling member H opposing luminous unit  42  of lamp  4  forms a reflection surface H 3 . The reflectance on the surface of reflection surface H 3  can be raised by application of a metal coating. As a result, light radiated from lamp  4  and light reflected from the inner surface of front optical guide  71  and then returned toward lamp  4  can be efficiently reflected in the direction of the aperture of front optical guide  71  to permit efficient wafer heating. 
     FIG. 6 is an explanatory figure showing another embodiment of the lamp unit. Coupling member H in lamp unit R 1  comprises contact fastening unit H 2  made of a block of aluminum and flat contact support unit H 1  of copper. When contact support unit H 1  contacts sealed part  41 , part of contact support unit H 1  forms projection H 11 . This projection H 11  mates with depression  411  of sealed part  41  to reliably support lamp  4 . On the other hand, the external shape of contact fastening unit H 2  is cylindrical, as shown in FIG.  7 . The outer diameter is roughly equal to the inner diameter of sleeve  5 . Contact fastening unit H 2  is pushed and press fit to the forward aperture of sleeve  5  with the outer circumference of contact fastening unit H 2  mated and fastened to the inner surface of sleeve  5 . 
     Contact support unit H 1  comprises a set of metal plates, one end of which is bent in advance, as shown in FIG.  7 . Furthermore, aforementioned projection H 11  is then formed with elasticity provided by this bending. Insertion aperture A of the lamp sealed unit of contact fastening unit H 2  is fitted in this state. When one end of contact support unit H 1  penetrates contact fastening unit H 2 , the other edge that penetrates and jumps out is bent as shown in FIG.  6 . Sealed part  41  of lamp  4  is press fit in the gap formed with opposing contact support unit H 1 , and both sides of sealed part  41  are pinched and supported by contact fastening unit H 2 . The surface of contact support unit H 1  of coupling member H that faces luminous unit  42  of lamp  4  then forms reflection surface H 3 . 
     FIG. 8 is illustrates an embodiment of the lamp unit whereby coupling member H in lamp unit R 2  has contact support unit H 1  and contact fastening unit H 2  as separate units. Contact support unit H 1  comprises a set of metal plates that are bent in prescribed shape, as shown in FIG. 9, to provide elasticity. This contacts both sides of sealed part  41  to pinch and support it. While lamp  4  is supported by contact support unit H 1 , it is fitted so as to contact the inner surface of contact fastening unit H 2  that is a ring-shaped metal unit. At this time, contact support unit H 1  is firmly fastened to contact fastening unit H 2  by the outward expansive elastic force of contact support unit H 1  and sealed part  41  is pinched and supported by contact support unit H 1 . Thick section  412  that is thicker than the surface of sealed part  41  is formed at the edge of sealed part  41  when sealed part  41  is molded. Thick section  412  engages ridge H 0  of contact support unit H 1  to prevent lamp  4  from being removed from contact support unit H 1 . 
     The outer diameter of contact fastening unit H 2  which is roughly equal to the inner diameter of sleeve  5  has an L-shaped notch B formed in one end, as shown in FIG.  10 . Contact fastening unit H 2  is press fit within sleeve  5  while guide section B 1  of notch B is situated within projection  51  that protrudes on the inner surface of compression molded sleeve  5  by punching the outer circumference of sleeve  5 . Subsequently, the fastening part B 2  of notch B mates with projection  51  by rotating contact fastening unit H 2 , as a result of which contact fastening unit H 2  is reliably mated in contact with the inner surface of sleeve  5 . 
     FIG. 11 illustrates another embodiment of the lamp unit whereby coupling member H in lamp unit R 3  comprises contact fastening unit H 2  made of a block of aluminum and flat contact support unit H 1  of copper. Contact support unit H 1  comprises a set of metal plates that are bent in prescribed shape, just as shown in FIG. 9, to provide elasticity so that contact support unit H 1  is firmly fastened to the inner circumferential surface of contact fastening unit H 2  through the outward expansive elastic force of contact support unit H 1 , and sealed part  41  is pinched and supported by contact support unit H 1 . The external shape of contact fastening unit H 2  is cylindrical, just as in embodiment  2 . The outer diameter is roughly equal to the inner diameter of sleeve  5 . Contact fastening unit H 2  is pushed and press fit to the forward aperture of sleeve  5  with the outer circumference of contact fastening unit H 2  mated while in contact with the inner surface of sleeve  5 . The portion of coupling member H that faces luminous unit  42  of lamp  4  then forms reflection surface H 3 . In this manner, light reflected off reflection surface H 3  can be reflected to the aperture side of optical guide  7  at high efficiency since reflection surface H 3  is a surface curved in hyperbolic or radiant shape. 
     The lamp units in accordance to the invention can solve the various problems associated with adhesive of conventional lamp units just like the lamp unit of embodiment  1 . Specifically, contamination of the interior of a processing chamber due to peeling of adhesive itself does not occur. The shorting of lead lines that supply power to lamp  4  due to the effects of moisture contained in adhesive does not take place. The decline in the reflectance due to contamination by moisture on the inner surface of optical guide  7  does not take place. Devitrification of the luminous tube due to moisture does not take place and the irradiation intensity is not attenuated since adhesive is not used. 
     Furthermore, sealed part  41  is connected to sleeve  5  by coupling member H. Since sleeve  5  is mated to optical guide  7  on its outer circumferential surface, heat from lamp  4  is transmitted to coupling member H via sealed part  41 . The heat transmitted to coupling member H is then transmitted to sleeve  5 . The heat transmitted to sleeve  5  is then transmitted to optical guide  7 . The heat transmitted to optical guide  7  is then transferred to the cooling liquid circulating on the outer surface. Consequently, a series of heat-conduction passages are formed that reliably cool lamp  4 . 
     Furthermore, light radiated from lamp  4  and light reflected off the inner surface of front optical guide  71  and then returned toward lamp  4  can be efficiently reflected in the direction of the aperture of front optical guide  71  to permit efficient wafer heating since the section of coupling member H opposing luminous unit  42  of lamp  4  forms reflection surface H 3 . 
     while the present invention has been described in connection with what is considered to be the most practical embodiments, it is understood that this invention is not limited to the disclosed embodiments and may reasonable encompass various arrangements included with in the spirit and scope of the broadest interpretations and equivalent arrangements.