TW445582B - Method of manufacturing metal conductive wire - Google Patents

Abstract

This invention is about the method of manufacturing metal interconnects. An insulating layer is formed on top of the dielectric layer and the conductive wire pattern is defined. Then, a barrier layer is formed on the surface of insulating layer and dielectric layer, in which metal seed is formed on the surface of this barrier layer. Electroplating or the other method is used to form a metal layer on the barrier layer. Finally, chemical mechanical polishing (CMP) method is used to strip the excess metal layer and the metal layer is undergone an annealing process. The layer of conductive-wire manufactured by using this method will reduce the generation of dishing and erosion, and is capable of lowering the resistance value and enhancing the electromigration resistance. Additionally, the defects such as rough surface of conductive wire and holes generated due to chemical mechanical polishing can also be eliminated.

Description

4 455 8 2 V. Description of the invention (l) 5-1 Field of the invention: The present invention relates to a technology of a metallization process, especially to a process technology of a wire. 5-2 Background of the Invention: In integrated circuits, the production of multi-level interconnects is started after the component body is completed. It is usually called the back-end process, and the The problem of metallization is most serious. Long signal transmission between components and components, roughly using metal wires that are easy to conduct electricity, traditional metallization process chooses aluminum as the main conductive material 'because it has a low resistance value of about 2. 8 microohm-cm' strong adhesion, easy to etch , And easy to integrate into an excellent ohmic contact (ohmic contact) and other advantages. But in the deep sub-micron field, the width of the wire is getting smaller and smaller. The resistance value of aluminum materials is gradually no longer applicable, so steel (cu) with a resistance value of 1.7 microohm-cm has a tendency to replace aluminum, so copper Wire process will be the future development direction. The traditional copper wire manufacturing process is as follows: pattern definition — forming a barrier — opening; ί seed (seed) — eiectr piping tempering (annea 丨 ing) — chemistry Mechanical grinding (CMp)

4455: 445b V. Description of the invention (2) The grain size of the copper material becomes larger after tempering, which can reduce the resistance value of the wire 'increasing the electron migration resistance' and release the stress inside the copper material, preventing it from deforming due to time. One method of chemical mechanical polishing is to flatten the Planarization. 'It is to smooth the contours of the wafer surface with different heights and heights, and use the mechanical polishing principle with an appropriate grinding spray (s 1 urry) to smooth it'. Production of a metal layer. ^ Zhongyan Polymer contains extremely hard abrasive particles and solvents. 'For a wafer with a predetermined pattern (wafer), in the area with a larger trench area' When the CMP is performed to the barrier layer, the copper metal layer and the barrier layer are on the same polishing plane, and the slurry is grinded for the same time Internally dissolves copper and barrier metal tantalum nitride (TaN), and at this time the selectivity (se 1 ectivity) of copper and nitride button is about 7 ~ 10, that is, the dissolution rate of the slurry solvent to copper It is 7 to 10 times that of tantalum nitride, so a dishing phenomenon will occur. However, in areas with a high pattern density, copper grains become larger and less harder after tempering, so they are less resistant to abrasive stress. Phenomena (errosion) are liable to occur, as shown in the first figure. The problems in the above two systems will cause the resistance of the wires to increase and bridges between the wires. In the existing process, a method is needed to overcome the dishing and pitting problems in order to increase the yield and expand the copper wire process parameter range (pr〇cess wind〇w). 5-3 Purpose and Summary of the Invention: In view of the disadvantages of the traditional process in the background of the invention,

4 4 5 5 8 2 5 'Explanation of the invention (3). ~ The main purpose of the present invention is to enable the production of multilayer metal interconnects to reduce the occurrence of dishing and pitting, so as to improve the yield of semiconductor processes. 'According to the above-mentioned purpose' An example of a method for manufacturing a steel wire of the present invention is to form an oxide layer on a dielectric layer and define a pattern of the wire, and then use a nitride group (TaN) as a barrier. Vapor deposition (CVD) is formed on all surfaces of the oxide layer and the dielectric layer. Phase > physical vapor depos iti on (forming copper seeds on this barrier layer, forming a copper metal layer by electroplating, and then combining chemical mechanical polishing to form copper wires on the barrier layer 'Finally, it is tempered to release the stress inside the copper material, reduce the resistance value and increase the electron migration resistance. 5-4 The diagram is briefly explained: The first figure shows the traditional process of tempering and then chemical mechanical grinding. Cross-section view of pitting and pitting; the second figure shows the cross-sectional view of the oxide layer after the wire pattern is defined by a photoresist layer; the third circle shows the cross-section view of the oxide layer with a defined pattern; the fourth figure shows the formation of the resist Sectional view behind barrier layer and steel metal layer;

d45C V. Description of the invention (4) The fifth figure shows the cross-section of the structure after chemical mechanical polishing. Representative symbols of the main part: 01 dishing phenomenon 02 pitting phenomenon 10 dielectric layer 11 oxide layer 12 photoresist layer 13 barrier layer 14 copper gold. Metal layer 5-5 Detailed description of the invention: The present invention is a traditional copper wire process Before the chemical mechanical polishing in China is moved to tempering, the new process is as follows: pattern definition-forming a barrier, forming seeds, electroplating-chemical mechanical polishing (CMP), tempering (Anneaiing) As shown in the second figure, an oxide layer 11 is deposited on the dielectric layer, and then a photoresist layer 12 is formed on the oxide layer 11, and the layer is layered with light. The pattern is defined and recorded 'after removing the photoresist layer 2 as shown in the third figure.

Page 7 445582 Five 'invention description (5) See the fourth figure, a chemical vapor deposition (CVD) layer is formed on all surfaces of the dielectric layer 10 and the oxide layer Η (TaN) ) Is used as the barrier layer 13 to prevent copper in the post-process from diffusing into the oxide layer 11 or the dielectric layer 10. In this step, the reason why TaN is selected as the material of the barrier layer 13 is that for the diffusion of copper atoms by the nitride button, it has a better isolation effect and a better adhesion ability. Then, a steel seed is formed on the barrier layer 13 by physical vapour deposition (PVD), and then a steel metal layer 14 is formed on the barrier layer ^ by electroplating. The copper metal layer 14 is chemical mechanical, copper 14 and nitrided giant (TaN) solvent. For metal steel and nitrogen agent, copper and nitride button (that is, the slurry is three times the steel, which is more than traditional The production of the process; and because it is still large at this time, it is not easy to generate trapping and tempering in the area where the grinding stress is relatively large. In addition to releasing the steel migration resistance to prevent the wire, 'For the chemical mechanical research ^. • called I jy rt, grinding method. When grinding to the barrier layer 13, it is on the same grinding plane, that is, both chemical groups in the slurry are dissolved.

The selectivity of TaN) is about 3, and the removal rate is about the barrier layer. It is much lower, so it can be reduced ^ Without tempering treatment, the copper grains are smaller, and the hardness is more resistant than the south, so it is in contact with the case density. In addition, after the chemical mechanical grinding, the internal stress of the material is prevented to prevent deformation, which increases the open circuit of ^ and reduces the resistance value ^

4 A 5 5: · V. Description of the invention (6) Defects (d e f e c t) ′ of the surface roughness and porosity of the copper wire caused by grinding are also eliminated due to the reorganization of the copper crystal. The above is only a preferred embodiment of the present invention, and is not intended to determine the scope of the claimed patent of the present invention; all other equivalent changes or modifications made without departing from the spirit disclosed by the present invention should be included in the following _ Within the scope of patents. Can be limited please

Claims (1)

4 455 Ο 6. Scope of patent application 1. A method for manufacturing a steel wire at least comprises: forming an oxide layer on a dielectric layer and defining a pattern of the wire; forming a barrier layer on the surface of the oxide layer and the dielectric layer y 'Copper seed is formed on the barrier layer by physical vapor deposition method;' A copper metal layer is formed on the barrier layer by electric recording method; Chemical mechanical polishing method is used to remove excess copper metal layer above the barrier layer The barrier layer; and the < ' > tempering layer temper the steel metal layer. 2. As the method of applying for the first item of the patent scope, the method of using a photomask and lithography is less available. The pattern is defined to the extent that the photoresist layer is used to define the pattern on the oxide layer, and unnecessary parts are removed. , And finally remove the photoresist layer. Then the etching method is adopted. 3. As in the method of the first patent application, the polishing selection ratio of the layer is about 3. 4. The copper and the barrier described above 4. A method for manufacturing a copper wire includes at least: forming an insulating layer on a dielectric layer and defining a wire pattern to form a barrier layer on the insulating layer and the dielectric layer A metal seed is formed on the barrier layer on the surface; a metal layer is formed on the barrier layer; the excess metal layer and the insulating layer are removed to temper the metal layer. Square of the barrier layer and 44558? 6. Application for Patent Scope 5. If the method of the scope of patent application No. 4 is applied, the above-mentioned wire pattern can be defined by at least a photomask and a lithography method to define the pattern on a photoresist layer, and then use the photoresist The layer defines the pattern on the insulating layer, and then removes unnecessary portions by etching, and finally removes the photoresist layer. 6. The method according to item 4 of the patent application, wherein the above-mentioned insulating layer includes at least silicon dioxide. 7. The method according to item 4 of the patent application, wherein the above barrier layer includes at least a nitride button (TaN). 8. The method according to item 4 of the patent application, wherein the above metal layer contains at least copper (Cu). 9. The method of claim 4 in which the above-mentioned metal layer can be formed at least by electroplating. 10. The method according to item 4 of the patent application, wherein the method for removing the excess metal layer includes at least a chemical mechanical polishing method.