Techno Semichem Co., Ltd. (Seongnam-si, KR discloses an improved nano-pore zeolite chemical mechanical polishing (CMP) composition for bulk copper in U.S. Patent Application 20100015807. The bulk copper CMP composition is used for polishing of a substrate containing a copper layer that is formed in a semiconductor fabricating process. The zeolite CMP has a high removal rate for the copper layer and a high selectivity of a copper layer with respect to a barrier layer as well as a minimized content of the complexing agent.
The zeolite is a porous material in which nano-pores having a desired size are regularly arranged. The zeolite can be classified into an aluminosilicate, an aluminophosphate (AlPO4), a silicoaluminophophate (SAPO) zeolite, a metal aluminophosphate (MeAPO) and a metallosilicate zeolite according to their composition.
Techno Semichem’s bulk copper CMP composition can control the dishing and corrosion (or etching) of the copper layer.
Inventors Seok-Ju Kim, Hyu-Bum Park, Eun-Il Jeong found a fact that, if a polishing slurry composition is comprised of zeolite, the polishing slurry composition can have a high removal rate for the copper layer and a high selectivity of a copper layer with respect to a barrier layer using a small amount of complexing agent.
The composition is characterized that zeolite is used to absorb the copper ions and realize mechanical polishing mechanism, more particularly, to a bulk copper CMP composition which comprises zeolite, a complexing agent and an oxidizer wherein the content of the complexing agent is 0.01.about.0.8 weight %.
The aluminosilicate-based zeolite can be expressed by a formula as follows: M2/nOxAl2OySiOzH2O, wherein M is a positive ion having an atomic value of n, z is a molecular number of water of crystallization, and a ratio of y/x is changed according to a crystal structure and typically has a value of 1 to about 100.
The zeolite generally has pores of about 5 to 20 angstrom (ANG) and a size of an entrance of the pores is 3 to about 13 .ANG. In general, the zeolite has a void volume of 15 to about 50%, a wide surface area of 200 m2/g or more, a low Mohr hardness of 2 to about 5 and a low density of 2 to about 3 g/cm3.
Since the zeolite has the internal pores with a large volume which receives a compound therein, when it is used in the CMP, the zeolite can comprise an useful compound before the CMP and also absorb and remove the copper ions after the CMP of the copper layer, thereby having an excellent polishing property. Further, since the zeolite has the lower hardness and density than the conventional inorganic particles, it is possible to restrict scratches generation during the polishing process.
Techno Semichem’s bulk copper CMP composition can control the dishing and corrosion (or etching) of the copper layer.
Inventors Seok-Ju Kim, Hyu-Bum Park, Eun-Il Jeong found a fact that, if a polishing slurry composition is comprised of zeolite, the polishing slurry composition can have a high removal rate for the copper layer and a high selectivity of a copper layer with respect to a barrier layer using a small amount of complexing agent.
The composition is characterized that zeolite is used to absorb the copper ions and realize mechanical polishing mechanism, more particularly, to a bulk copper CMP composition which comprises zeolite, a complexing agent and an oxidizer wherein the content of the complexing agent is 0.01.about.0.8 weight %.
The aluminosilicate-based zeolite can be expressed by a formula as follows: M2/nOxAl2OySiOzH2O, wherein M is a positive ion having an atomic value of n, z is a molecular number of water of crystallization, and a ratio of y/x is changed according to a crystal structure and typically has a value of 1 to about 100.
The zeolite generally has pores of about 5 to 20 angstrom (ANG) and a size of an entrance of the pores is 3 to about 13 .ANG. In general, the zeolite has a void volume of 15 to about 50%, a wide surface area of 200 m2/g or more, a low Mohr hardness of 2 to about 5 and a low density of 2 to about 3 g/cm3.
Since the zeolite has the internal pores with a large volume which receives a compound therein, when it is used in the CMP, the zeolite can comprise an useful compound before the CMP and also absorb and remove the copper ions after the CMP of the copper layer, thereby having an excellent polishing property. Further, since the zeolite has the lower hardness and density than the conventional inorganic particles, it is possible to restrict scratches generation during the polishing process.
Further, due to the properties of the zeolite, it is possible to reduce the content of the complexing agent contained in the conventional copper polishing slurry composition, it is possible to provide a high removal rate for the copper and a high selectivity of a copper layer with respect to a barrier layer using a small amount of the complexing agent and also reduce occurrence of the dishing and corrosion
The method of pulverizing the zeolite includes the milling, hi-mixing and fluid impacting methods. In the milling method, the zeolite is mixed with beads and then stirred at a high speed by using a bead mill, a Dynomill, a ballmill and an attrition mill. In the hi-mixing method, the fluid is rotated at a high speed by using a rotor and struck against a stator so as to produce friction. Further, the fluid impacting method is an oppositely impacting method. During the pulverizing process of the zeolite, native crystallinity of the zeolite may be reduced or lost. However, such the pulverized zeolite can be used in the present invention.
The bulk copper polishing composition may also contain one or more additives such as an anticorrosive agent, a surfactant, aminoalcohol, a water-soluble polymer, an anti-foaming agent and a fungicide, and also further comprise abrasive particles having a mechanical polishing function.
