Adhesive bonding and miscellaneous chemical manufacture – Differential fluid etching apparatus – For liquid etchant
Reexamination Certificate
2000-10-25
2003-08-05
Utech, Benjamin L. (Department: 1763)
Adhesive bonding and miscellaneous chemical manufacture
Differential fluid etching apparatus
For liquid etchant
C156S345150, C118S323000, C118SDIG004
Reexamination Certificate
active
06602382
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a solution processing apparatus for supplying a developing solution to the surface of a substrate, for example, a semiconductor wafer or the like which has been coated with a resist and subjected to exposure processing to thereby perform developing processing.
In semiconductor device fabrication, a photoresist is applied to a semiconductor wafer as a substrate to be processed, a mask pattern is transferred to the photoresist by exposure processing, and the photoresist is subjected to developing processing to thereby form a circuit pattern.
In a developing processing step here, the so-called puddle method, in which a developing solution is particularly continuously supplied from a nozzle to the semiconductor wafer and heaped on a face on which a pattern will be formed only for a predetermined period of time for a contact therebetween to thereby develop a latent pattern in the applied resist film, is generally employed.
A puddle method using the so-called linear nozzle in which many solution discharge ports are arranged in a straight line at predetermined intervals is the current mainstream. Developing methods using the above linear nozzles are roughly divided into (1) “a rotation method” of performing solution heaping on the wafer by rotating the wafer 180° while the developing solution is being discharged from the linear nozzle, and (2) “a scan method” of performing solution heaping by horizontally moving the linear nozzle in one direction with respect to the wafer without rotating the wafer.
The former rotation method is invented from a recent demand for saving of consumption of a developing solution and that solution heaping is performed in a short time and uniformly. However, by the rotation method, there may be cases where chips in the vicinity of the central portion of the wafer that is the rotational center become defective pieces depending on the type of resist.
More specifically, the solution heaping of the developing solution is performed over the entire wafer by rotating the wafer 180° with the nozzle being fixed in the rotation method. By such a method, a fresh developing solution is supplied only to a part close to the central portion of the wafer, and thus it is conceivable that development excessively proceeds only at this part compared with a peripheral part. With micro-machining and higher density in recent circuit pattern, resists have been improved in performance, that is, increased in resolution. Accordingly, problems that have been neglected before are coming up, and, for example, in the case in which a chemically amplified resist (CAR) is used, there is a problem that the aforesaid phenomenon obviously occurs, whereby a desired resolution can not be obtained.
On the other hand, by the scan method, though it takes a slightly long time for solution heaping compared with the aforesaid rotation method, the above problem does not occur, and thus this method is recognized as a promising method in recent years.
In the scan developing method, the aforesaid linear nozzle is used to discharge the developing solution from many discharge ports at the same time with the discharge ports being brought close to the surface of the wafer. Then, the linear nozzle is horizontally moved (scan-moved) in parallel to the surface of the wafer to thereby form a developing solution film on the wafer.
The linear nozzle here is configured such that after the developing solution is stored in a solution storage portion provided therein, pressure is applied to the solution storage portion to thereby discharge the developing solution via the aforesaid many discharge ports. In this case, solutions supplied from the discharge ports in the form of vertically split screen spread out to some extent above the surface of the wafer, and adjacent solutions unite with each other to be supplied onto the wafer in curtain form or film form. Then, the linear nozzle is moved in accordance with the discharge speed of the developing solution, whereby the solution flow in film form can be mounted on the wafer.
The important thing in the developing method as described above is that the developing solution is uniformly discharged from all the discharge ports to form a solution flow in film form with a uniform thickness. Just after the discharge, however, the thickness is prone to become nonuniform. Further, depending especially on the type of resist to be applied to the wafer, it is necessary to reduce the discharge amount and the discharge speed of the developing solution so as to decrease the influence of impact and the like exerted on the resist. In this case, it becomes further difficult to form a solution flow in film form with a uniform thickness.
On the other hand, there is a linear nozzle provided with a discharge port in slit form having a length corresponding to a diameter of the wafer. This nozzle is generally called a slit nozzle, in which unevenness in discharge pressure is prone to occur, and therefore it is further difficult to form a solution flow in film form with a uniform thickness.
Moreover, in the above-described method, the supply nozzle is moved with a tip of the supply nozzle contacting the developing solution supplied on the wafer, and thus if a supply nozzle made of a hydrophobic material is used, the developing solution is rejected by the surface of the nozzle and it becomes difficult to supply the developing solution to the surface of the wafer in a uniform state, bringing about a problem that development unevenness is likely to occur.
In the case in which a supply nozzle made of a hydrophilic material is used, the developing solution is brought into a state of being pushed out when the supply nozzle is moved at a low scan speed, for example, at about 50 mm/sec, with the result that the developing solution flows to a position ahead of the nozzle in respect to a direction of movement of the nozzle. If the developing solution flows ahead of the supply nozzle as described above, development proceeds at this part, and thereafter the supply nozzle moves to this part and the developing solution is supplied thereto, which is the same as a state in which development is performed twice for this part, development proceeding too much compared with other parts, resulting in nonuniform line width.
If a phenomenon of the developing solution flowing ahead occurs over the entire wafer W and every part is brought to a state of being subjected to development twice here, occurrence of development unevenness can be prevented. However, the developing solution actually flows ahead at some parts and not at other parts, resulting in occurrence of development unevenness and nonuniform line width.
BRIEF SUMMARY OF THE INVENTION
An object of the present invention is to provide a solution processing apparatus capable of discharging a developing solution uniformly from all discharge ports even when, for example, discharge pressure for the developing solution to be supplied is low in development of a scan method using a linear nozzle or a slit nozzle.
Another object of the present invention is to provide a solution processing apparatus capable of performing uniform solution processing on the surface of a substrate.
To attain the above objects, with a primary aspect of the present invention, provided is a developing processing apparatus for supplying a developing solution to a substrate to be processed on which a photoresist film has been formed to thereby perform developing processing, including: a substrate holding mechanism for horizontally holding the substrate to be processed; a developing solution supply nozzle held above the substrate holding mechanism for supplying the developing solution onto the substrate to be processed while moving in a predetermined horizontal direction; and discharge resistance imparting means, disposed behind the substrate in a direction of movement of the developing solution supply nozzle, for imparting discharge resistance to the developing solution discharged from the nozzle.
With the above configuration, the discha
Matsuyama Yuji
Nagamine Shuichi
Moore Karla
Rader & Fishman & Grauer, PLLC
Tokyo Electron Limited
Utech Benjamin L.
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