Semiconductor manufacturing apparatus, method of detecting abnormality, identifying cause of abnormality, or predicting abnormality in the semiconductor manufacturing apparatus, and storage medium storing computer program for performing the method
In order to detect an abnormality of semiconductor manufacturing apparatus, a biaxial coordinate system having first and second axes respectively assigned two different monitoring parameters selected from plural apparatus status parameters representing statuses of semiconductor manufacturing apparatus is prepared. As monitoring parameters, for example, a cumulative film thickness for deposition processes that have previously been performed in deposition apparatus and an opening of the pressure control valve located in a vacuum exhaust path to control the internal pressure of a reaction vessel are selected. Values of monitoring parameters obtained when the semiconductor manufacturing apparatus was normally operating are plotted on the biaxial coordinate system. A boundary between a normal condition and an abnormality status is set around a plot group. Values of monitoring parameters obtained during present operation of the semiconductor manufacturing apparatus are plotted on the biaxial coordinate system to determine whether or not there exists an abnormality and identify a type of abnormality based on a positional relation between the plots and the boundary.
1. A semiconductor deposition apparatus that includes a reaction vessel and is configured to perform a deposition process on substrates in the reaction vessel to fabricate a semiconductor device, said apparatus comprising:
a boundary data storage unit that stores boundary data defining a boundary between a normal region and an abnormal region on a biaxial coordinate system, the coordinate system having a first axis and a second axis respectively assigned a first monitoring parameter and a second monitoring parameter that varies according to a correlation with the first monitoring parameter;
first and second monitoring means for monitoring the first and second monitoring parameters, respectively;
batch size selection means for selecting a batch size which represents the number of substrates processed by a single process in the reaction vessel;
judgment means for judging whether a position, on the biaxial coordinate system, of a combination of values of the first and second monitoring parameters respectively obtained by the first and second monitoring means is included in the normal region or in the abnormal region; and
abnormality alarming means for alarming that there exists an abnormality in the semiconductor deposition apparatus if the judgment means determines that the position is included in the abnormal region, wherein
the first monitoring parameter is a cumulative film thickness which represents the sum of the thickness of films which have been deposited in the reaction vessel, and the second monitoring parameter is an opening of a pressure control valve which is arranged in a vacuum exhaust path to control pressure in the reaction vessel;
the boundary data storage unit stores a plurality of boundary data respectively corresponding to different batch sizes;
the judgment means is configured to make a judgment based on boundary data corresponding to a selected batch size; and
if the judgment means determines that the position is included in the abnormal region, the abnormality alarming means is configured to alarm that the air-tightness of the reaction vessel is insufficient or that cleaning is necessary.
2. The semiconductor deposition apparatus according to claim 1 , further comprising:
correlation data creation means for creating correlation data representing a correlation between the first and second monitoring parameters on the biaxial coordinate system based on a number of combinations of corresponding values of the first and second monitoring parameters obtained when the semiconductor deposition apparatus is in a normal condition; and
boundary data creation means for creating boundary data that defines the boundary between the normal region and the abnormal region on the biaxial coordinate system based on correlation data created by the correlation data creation means.
3. The semiconductor deposition apparatus according to claim 2 , further comprising an apparatus data storage unit that stores a history of the apparatus status parameters, wherein
the correlation data creation means is configured to create the correlation data based on the apparatus status parameters corresponding to the first and second monitoring parameters stored in the apparatus data storage unit.
4. The semiconductor deposition apparatus according to claim 2 , further comprising display means for displaying the correlation data.
5. The semiconductor deposition apparatus according to claim 4 , wherein the display means is configured to display the correlation data and the boundary data on a single common biaxial coordinate system.
6. The semiconductor deposition apparatus according to claim 2 , wherein
the boundary data creation means includes means for selecting an approximate expression for defining the boundary; and
means for calculating coefficients in the approximate expression based on the correlation data and the selected approximate expression.
7. The semiconductor deposition apparatus according to claim 1 , further comprising:
a heater composed of a resistance heating element provided around the reaction vessel to heat an inside of the reaction vessel; and
a temperature sensor that detects a temperature of the heater.
8. A method of detecting an abnormality of a semiconductor deposition apparatus that includes a reaction vessel and is configured to perform a deposition process on substrates in the reaction vessel, comprising the steps of:
acquiring a value of a first monitoring parameter and a value of a second monitoring parameter which varies according to a correlation with the first monitoring parameter;
selecting one of a plurality of boundary data that respectively corresponds to a specific batch size to be processed;
applying the acquired values of the first and second monitoring parameters to the selected boundary data that specifies a boundary between a normal region and an abnormal region on a biaxial coordinate system having a first axis and a second axis respectively assigned the first and second monitoring parameters;
judging whether a position of the acquired values of the first and second monitoring parameters are included in the normal region or the abnormal region of the selected boundary data on the biaxial coordinate system; and
alarming that there exists an abnormality in the semiconductor deposition apparatus if the judgment means judges that the positions of the acquired values are included in the abnormal region, wherein
the first monitoring parameter is a cumulative film thickness which represents the sum of the thicknesses of films which have been deposited in the reaction vessel and the second monitoring parameter is an opening of a pressure control valve which is arranged in a vacuum exhaust path to control pressure in the reaction vessel, and
the alarming step includes an alarm that signals that air-tightness of the reaction vessel is insufficient or that cleaning is necessary.
9. A storage medium storing a computer program therein, wherein when a computer connected to the semiconductor deposition apparatus executes the computer program, the computer controls the semiconductor deposition apparatus to perform the method according to claim 8 .