Substrate polishing apparatus
A substrate polishing apparatus is provided for preventing excessive polishing and insufficient polishing, and enabling a quantitative setting of an additional polishing time. The substrate polishing apparatus comprises a mechanism for polishing a substrate to be polished; a film thickness measuring device for measuring the thickness of a thin film deposited on the substrate; an interface for entering a target thickness for the polished thin film; a storage area for preserving past polishing results; and a processing unit for calculating a polishing time and a polishing rate. The substrate polishing apparatus builds an additional polishing database for storing data acquired from the result of additional polishing in the storage area.
1. A polishing method, comprising:
polishing a substrate having a layer deposited on a surface of the substrate in a regular polishing process, said regular polishing process comprising polishing the substrate until an in-situ process monitor senses predetermined layer thickness of the substrate and, then, over-polishing the substrate for a predetermined time which corresponds to a difference between a desired layer thickness and the predetermined layer thickness sensed by said in-situ process monitor;
measuring a layer thickness of the substrate after said regular polishing process as a first thickness using an in-line film thickness measuring device to detect an unfinished polishing portion;
polishing the substrate in an additional polishing process to remove the unfinished polishing portion of the layer if said in-line film thickness measuring device detects the unfinished polishing portion;
measuring a layer thickness of the polished substrate after said additional polishing process as a second thickness with said in-line film thickness measuring device;
calculating a polishing rate of said additional polishing process from said first thickness, said second thickness and an amount of polishing time of said additional polishing process;
storing a database with first data that comprises at least one of the layer thickness, the polishing time and the polishing rate of said additional polishing process; and
extending an over-polishing time, based on the first data, used to polish a subsequent substrate.
2. The polishing method of claim 1 , and further comprising:
storing the database with second data that comprises at least one of a layer thickness, a polishing time and a polishing rate in said regular polishing process.
3. The polishing method of claim 2 , and further comprising:
optimizing an amount of polishing time in said regular polishing process based on said first data and said second data as a polishing time of the subsequent substrate.
4. The polishing method of claim 3 , and further comprising:
calculating a relational equation between a polishing amount and a polishing time from two or more points stored in said database.
5. A polishing method, comprising:
polishing a substrate having a layer deposited on a surface of the substrate in a regular polishing process, said regular polishing process comprising polishing the substrate until an in-situ process monitor senses a predetermined layer thickness of the substrate, and then over-polishing the substrate for a predetermined time which corresponds to a difference between a desired layer thickness and the predetermined layer thickness sensed by said in-situ process monitor;
measuring a layer thickness of the substrate after said regular polishing process as a first thickness using an in-line film thickness measuring device and detecting an unfinished polishing portion;
polishing the substrate in an additional polishing process to remove the unfinished polishing portion of the layer;
measuring a layer thickness of the polished substrate after said additional polishing process as a second thickness with said in-line film thickness measuring device;
calculating a polishing rate of said additional polishing process from said first thickness, said second thickness and an amount of polishing time of said additional polishing process;
storing a database with first data that comprises at least one of the layer thickness, the polishing time and the polishing rate of said additional polishing process; and
polishing a subsequent substrate in said regular polishing process with an extended over-polishing time that is extended based on the first data.
6. The polishing method of claim 5 , and further comprising:
storing the database with second data that comprises at least one of a layer thickness, a polishing time and a polishing rate in said regular polishing process.
7. The polishing method of claim 6 , and further comprising:
optimizing an amount of polishing time in said regular polishing process based on said first data and the second data as a polishing time for the subsequent substrate.
8. The polishing method of claim 7 , and further comprising:
calculating a relational equation between a polishing amount and a polishing time from two or more points stored in said database.