Semiconductor device manufacturing: process – With measuring or testing
Reexamination Certificate
2003-01-24
2004-09-07
Thompson, Craig A. (Department: 2813)
Semiconductor device manufacturing: process
With measuring or testing
C438S907000, C438S909000, C438S935000, C374S102000, C374S137000
Reexamination Certificate
active
06787377
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a determining method of a control condition for a thermal (heat) processing system that carries out a thermal process for an object to be processed such as a substrate. In particular, the present invention relates to a determining method of a control condition of a thermal processing system for forming a uniform film on a substrate.
BACKGROUND ART
For a semiconductor-device manufacturing process, as one of units that carry out a heat process to a semiconductor wafer (hereafter, a wafer) as a substrate, there is a vertical type of thermal processing unit that carries out a batch process. The unit holds many wafers in a tier-like manner with a wafer holder, which is called a wafer boat or the like, and transfers the holder into a vertical heat-processing furnace to conduct a CVD (Chemical Vapor Deposition) process or an oxidation process.
When a wafer undergoes a heat process by means of the thermal processing unit, ununiformity may arise in a condition of the heat process within a surface of the same wafer or between a plurality of wafers. As a result, unevenness in thickness distribution of a film formed by the heat process may be generated within a surface of the same processed wafer or between a plurality of processed wafers.
It is ideal that there is a uniform state in the thermal processing unit in order to uniformly conduct a heat process to a plurality of wafers. However, it is difficult to always make a state in the thermal processing unit uniform with respect to both time and space.
Therefore, it is necessary to precisely control the thermal processing unit in order to conduct a heat process to a plurality of wafers under a more uniform condition.
The present invention has been made to solve such a problem and it is an object of the present invention to provide a method of determining a control condition for uniformly conducting a heat process to a plurality of wafers by means of a thermal processing unit.
In addition, in a conventional heat processing unit, a stabilization time is required to make a temperature of a substrate stable, for a purpose of conducting a heat process uniformly within a surface of the substrate. Thus, it takes a long time to conduct the heat process by the stabilization time, so that the throughput is deteriorated.
The present invention has been made to solve such a problem and it is an object of the present invention to provide a heat processing unit that can carry out a heat process uniformly within a surface of a substrate even if the stabilization time is shortened.
DISCLOSURE OF THE INVENTION
The present invention is a method of determining a set temperature profile for a method of controlling respective substrate temperatures of a plurality of groups in accordance with respective corresponding set temperature profiles, in a method of heat processing a plurality of substrates that are classified into the plurality of groups, the method of determining a set temperature profile comprising: a first heat processing step of controlling respective substrate temperatures of a plurality of groups in accordance with respective predetermined provisional set temperature profiles for first-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a first film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a first set-temperature-profile amending step of respectively amending the provisional set temperature profiles based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups; wherein, in the first heat processing step, the provisional set temperature profiles are profiles whose set temperatures change as time passes.
Thickness distribution of the films between the substrates can be made uniform, by amending the provisional set temperature profiles that are profiles whose set temperatures change as time passes.
It is preferable to maintain substantially the same patterns except components of constant terms (offsets) when amending the provisional set temperature profiles. In the case, it becomes difficult for thickness distribution within a substrate to change between before and after the amendment.
Preferably, in the first heat processing step, set temperatures of the provisional set temperature profiles have a substantially constant gradient with respect to time. Steepness of the gradient is a factor that determines temperature distribution within a surface of the substrate. By making the gradient constant, temperature distribution during the heat process and hence distribution of film-forming rate can be made constant with respect to time.
Preferably, in the first film-thickness measuring step, for at least one substrate in each of the plurality of groups, film thickness is measured at a plurality of points of each substrate, and an average of the measured values is obtained as a film thickness of the substrate.
Preferably, in the first set-temperature-profile amending step, averages of ideal set temperatures to be amended are calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness, and the provisional set temperature profiles are amended based on the averages.
Averages of the set temperatures are factors that correspond to averages of film-growing rates. Thus, it is effective to make film-thickness distribution uniform based on the averages of the set temperatures.
The thickness-temperature dependant relationship can be represented for example by a thickness-temperature coefficient. In addition, as a thickness-temperature dependant relationship, a theoretical equation can be used. Values obtained from experiments can be also used.
Preferably, the present invention is a method of determining a set temperature profile according to claim
1
, further comprising after the first set-temperature-profile amending step: a second heat processing step of controlling the respective substrate temperatures of the plurality of groups in accordance with respective amended first set temperature profiles for second-batch substrates that are classified into the plurality of groups, and of introducing a process gas to conduct a heat process to form films on the substrates; a second film-thickness measuring step of measuring a thickness of the films formed on the substrates; and a second set-temperature-profile amending step of respectively amending the first set temperature profiles based on the measured thickness, in such a manner that a thickness of films formed during a heat process is substantially the same between the plurality of groups.
Preferably, in the second set-temperature-profile amending step, averages of ideal set temperatures to be amended are calculated based on a thickness-temperature dependant relationship between the substrate temperatures and the film thickness, and the first set temperature profiles are amended based on the averages.
Preferably, in the second set-temperature-profile amending step, the thickness-temperature dependant relationship between the substrate temperatures and the film thickness is amended based on: averages in time of the provisional set temperature profiles during the first heat processing step, film thickness of the films on the first-batch substrates, averages in time of the first set temperature profiles during the second heat processing step, and film thickness of the films on the second-batch substrates.
Preferably, the second heat processing step, the second film-thickness measuring step and the second set-temperature-profile amending step are repeated at least twice in order thereof.
In addition, the present invention is a method of determining a set temperature profile for a method of controlling respective substrate temperatures of a plurality of groups in accordance with respective corresponding set temperature profiles, in a method of heat processi
Sakamoto Koichi
Suzuki Fujio
Wang Wenling
Yasuhara Moyuru
Berezny Nema
Smith , Gambrell & Russell, LLP
Thompson Craig A.
LandOfFree
Determining method of thermal processing condition does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Determining method of thermal processing condition, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Determining method of thermal processing condition will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3198200