TW200540145A - Method and composition to enhance wetting of ecp electrolyte to copper seed - Google Patents

Abstract

A composition and method which substantially enhances the wetting of an electrolyte solution to a surface in the electrochemical plating of a metal such as copper on the surface. The composition is an organic mixture which includes an organic acid, such as citric acid or acetic acid, and a low molecular weight non-ionic polymer such as an alcohol, an amine or alkyphenol alkoxylate. The method includes suspending the composition as a layer in the solution and passing the surface through the composition suspension layer to define a wetting layer on the surface. Consequently, metal electroplated onto the surface is substantially devoid of pits or other structural defects.

Description

200540145 IX. Description of the invention: [Technical field to which the invention belongs] The present invention relates to a method for depositing a metal layer on a semiconductor wafer substrate in the manufacture of semiconductor integrated circuits. [Conductor wafer sub wheel: (ECP) process' More specifically, the invention relates to a method and composition for promoting the wettability of the electrochemical clock electrolyte to the metal seed layer when the metal layer of an electrochemical clock such as copper metal is on a substrate. [Previous Technology] ♦ In the manufacture of semiconductor integrated circuits, metal wires are often used to connect multiple materials in semiconductor circuits. The general process of depositing gold wire fermentation on a semiconductor wafer includes: depositing an electrical layer on the Shi Xi substrate to form a photoresist or other photomask layer such as titanium oxide or stone oxide. The standard lithography technique requires the extraction of gold wires to the base line to remove the conductive layer in the area not covered by the mask, so as to order the metal layer formed by the wire pattern; and the use of a regular reaction formula Plasma and chlorine gas are used to remove the photomask layer, thereby exposing the upper surface of the metal wire. -Multiple alternating layers formed by conductive materials and insulating materials are sequentially deposited on the substrate; and the interlayer window or opening is carved out by the money in the insulating layer, and the chain or opening is filled in the chain After cranes, cranes or other metal materials, the conductive layers belonging to different layers can be electrically connected by side channels or openings in the insulating layer through the established electrical connection portions. The deposition of the conductor layer on the wafer substrate can be accomplished by using various techniques. For example, oxidizing low-level chemical vapor deposition (LpCVD), atmospheric pressure chemical vapor deposition (APCVD), and electro-enhanced chemical vapor deposition (pECVD). -In general, chemical vapor deposition is a type of integrated vapor circuit chemical that contains the required deposition components to form a non-volatile 4 film on the wafer substrate and vapor deposition on the substrate. Among them, it is the most widely used; there is no method for depositing a thin film on a wafer substrate.

Due to the gradual reduction in the size of semiconductor parts and the gradual increase in the density of integrated circuits on the wafer, the complexity of interconnecting circuit parts forces the wire to define the metal wire. The manufacturing process must be 0503-A31535TWF 5: 200540145 / page for precise size control. More advanced «political shirt and mask technology, and dry etching processes, such as reverse ion money engraving (R positive) and Dotari will ^ ', water etching process, can make the pattern line width and spacing in the sub-micron Made in the fence. In the field of flat-panel displays and manufacturing of conventional and custom-manufactured road garments, the process of depositing a metal on the substrate or depositing a conductive layer on the substrate has been identified as a specific technology. The f-type deposition technique has enabled the deposition of other metal layers so that they have a smooth upper surface. Therefore, the current development focus is on the design of electrical and mining hardware equipment and chemicals, in order to raise the product film or conductive layer, so that it has uniformity on the entire surface of the substrate, and this is enough to meet the characteristics of extremely small devices. Copper has been found to have special advantages. The application of the Jiji Road (1C) has several advantages. Copper has a smaller resistivity and therefore can operate current at higher frequencies. And copper is more resistant to electromigration than chains (dec plus migration, EM). Reliability can be increased on a semiconductor device because if the circuit has a higher current density or a lower resistance to electromigration, it is easy to create voids or open circuits at metal connections. These holes or open circuits can cause the device to malfunction or burn out. A traditional metal plating system such as copper is deposited on a semiconductor wafer. It consists of a clock unit with an adjustable current source, a container containing an electrolyte solution (usually an acidic copper sulfate solution), and copper. The anode and the cathode are immersed in an electrolyte solution. The cathode is a semiconductor wafer that is used to plate metal. The anode and the semiconductor crystal (J (cathode)) are connected to the current source by a wire. The electrolyte solution may contain an additive for the filling of sub-micron patterns and planarize the surface of copper plating on the wafer. It can also be connected to an electrolyte containing The storage tank is connected to the liquid container to add the electrolyte solution that needs to be replenished in the liquid container. In the operation of the electric money system, the current source provides a predetermined voltage potential between the anode and the cathode (wafer) to operate at room temperature. The potential creates a magnetic field between the anode and the cathode (wafer), and the magnetic field affects the distribution of copper ions in the container. In a typical copper plating application, a voltage of about 2 volts can operate for about 2 minutes. And a current flow of about 4 · 5 amps (amps) 0503-A31535TWF 6 200540145 through the anode and the cathode ..., when the pen is left from the copper anode, the copper will be converted in the anode # and sulfur in the solution in the container The formation of the interface between the milk ion at the copper ion surface and the copper sulfate solution-electroplated copper. The, and * electrodes (wafers) The Wei reflection at the anode is expressed by the following equation: Cu ^ CvT + lo Gu ^ § 20 Morning oxidation After copper ion (cation) reaction produces ionized copper sulfate: with sulfate ion (anion) in solution

Cu ++ + SO, + Οιΐο # ~

The copper in the copper sulfate solution at the cathode 'wafer' interacts with the electrons and cations (cations) flowing through the wire from the anode, and the electricity is mined to the cathode (wafer Cu ^ + 2e'Cu as the bottom During the deposition, for example, using an electrochemical clock, a steel metal layer must be deposited on the crystal layer, and this crystal layer is deposited before the copper electrochemical plating (Ecp) process. The seed layer on the substrate can be Various methods of deposition, such as physical vapor deposition (pv ^ and chemical vapor deposition (CVD). Generally speaking, the metal seed layer is thinner than the conductive metal layer on the semiconductor wafer substrate> about 5 〇_150 Angstrom (person) thick). There may be many problems with the metal seed layer deposited on the substrate, such as the presence of metal oxides on the seed layer or discontinuities in the seed layer, and the pollution and contamination of the layer. _Formation problems. This shortcoming will cause uneven production of Weihe quality on the surface of the seed layer. The unevenness and degree of the electrolyte solution of the layer will lead to structural considerations, such as the cavity of the Weijin system on the seed layer. Endangers the structure and function of IC devices . Yi Chuan = used to improve the wet turbidity of the electrolyte solution of the metal seed crystal clock, including pi'e-rinsing or pr_ealing on the surface of the seed layer. The results are not good. Therefore, a new and improved composition and method are needed to increase the wet turbidity of the electrolyte solution above the metal seed layer when electrochemical copper or other metals are deposited on a substrate. The object of the present invention is to provide a Novel composition and method for clock gold on seed layer

0503-A31535TWF 7 200540145 Before the genus', the seed layer on the substrate is pretreated or wetted. Another object of the present invention is to provide a kind of _synthetic cleavage chemical electroplating copper or other metal, which is used to increase the moisturizing degree of Jinding, Tuotai and m w stomach solution. Another purpose of this book is to provide a new type of composition and method, in which the structural defect on the basal seed layer can be avoided qualitatively. "High gap filling ability. Chuxian, and hunting by the improvement of wettability, Furthermore, another object of the present invention is to provide a planar composition and method for electrifying the seed layer, thereby reducing the contact angle of the electrolyte solution to the seed layer. [Summary of the Invention] In view of this and other objectives and benefits The present invention broadly indicates a composition and method for increasing the wettability of the seed layer electrolyte solution on the substrate when electrochemically weird metals (such as copper) are grown on the seed layer. This composition is an organic mixture containing _ Organic acids, such as jtnc acM) or acetic acid, and a low molecular weight non-ionic polymer, such as alkoxylated alcohols (such as hdalkoxylate), aminealk () xylate, or Oxygenated alkane test 〇1 coffee 11_ industry. \ Shuai). «Benfa. Finance method,-metal seed crystal layer is deposited in advance on the substrate h preparation-electric scale (Ecp) electrolytic f solution, and preparation ^ Organically synthesized mixture as electrolyte solution The base layer with the metal seed layer deposited on the weaving surface 'moves through the suspended synthetic mixture layer and enters into the electrolytic solution of the electrochemical vessel (ECp); so that some compounds adhere to the wet layer on the seed layer, and Improve the wettability of the electrolyte solution of the metal seed layer on the substrate. Then the substrate is suspended in the solution for electrochemical plating. The electric boat metal forms a metal layer with high structural integrity, which substantially avoids pits or other surfaces on the entire surface of the seed layer Structural defects. [Embodiment] 0503-A31535TWF 8 200540145 The present invention has a beneficial effect, which is beneficial for the wet inclusion of copper seed layer electrolyte solution on a semiconductor wafer substrate, and for the fabrication of semiconductor integrated circuits. The structural quality of the copper metal layer on the crystal layer. However, the present invention is more widely applied to the wettability of other non-copper metal seed layer electrolyte solutions; and for different industrial applications, the substrate-plated metal (not limited to copper), The invention has broadly pointed out a composition and method for electrochemically plating (Ecp) a metal (special) on a seed layer. It is copper), which increases the wettability of the seed layer electrolyte solution on the substrate. Compared with the seed layer of the untreated control group, the composition significantly reduces the contact angle of the electrolyte solution on the seed layer. Gj Therefore, the metal on the seed layer can substantially avoid pits and other structural defects on the entire surface of the seed layer. The composition in the present invention includes an organic acid, such as citric acid or citric acid ( acetic acid), and mixtures of non-ionic polymers, such as alkoxylated alcohols (alcohol alkoxylate), alkoxylated amines (aminealkoxylate) or alkoxylated alkphenols (alkyphenoi alkoxylate). This nonionic polymer is preferably a low molecular weight nonionic polymer (less than about 1000 MW). Organic acids are present in the synthesis mixture in particular in a concentration-to-weight ratio of about two to twenty percent (2 to 20%). Non-ionic polymers are present in the synthesis mixture in particular in a concentration-to-weight ratio of about five to ten percent φ ten (5 to 10%). In one embodiment, the composition comprises an organic acid, such as citric acid or acetic acid, and an alkoxylated alcohol, such as an ethoxylated alcohol polymer ( ethoxylated alcohol polymer). The composition preferably contains an organic acid in an amount of approximately ten percent by weight (10 wt ·%), and an alkoxylated alcohol in an amount of approximately five percent (5 milk ·%) by weight. In another embodiment, the composition comprises an organic acid, such as citric acid or acetic acid, and an alkoxylated amine polymer, such as an ethoxylated diamine. Polymer (ethoxylated diamine polymer), mixture. The composition preferably contains a special weight ratio of about ten percent (10 wt.%) Organic acid, and a special weight ratio of about 10503-A31535TWF 9 200540145 five-fifths (5 wt ·%) amine. In the other male and Guanzhong σ-formation system contains an organic acid, such as citric acid or 1cacid, and oxygenated (~ wulk〇xylate), the best combination Contains 10% organic acid by weight, and organic acid, and about 5% by weight (5wt%) oxidized by oxygen. Figure 1A of Cangkao, one of the electrochemical electric clock (EO >) systems 10 applicable to the present invention, which includes-a standard electric mine early fan 'which has-an adjustable current source 12, a container 14, a copper anode M and a The cathode 18, wherein the cathode 18 is used to electro-mine copper half wafer substrate. The anode 6 and the cathode (Kirudi) 1S are connected to the current source U with a suitable lead 38. The container M has a liquid such as, in particular, an acidic copper sulfate solution, which can include-additions-puffing underfill, and The surface of the electroplated copper on the substrate 18 is flattened. The packaged chemical electron microscope (ECP) system 10 further includes a pair of shunt filter ducts 24, a shunt poly (filter, filter) 3G, and a storage tank with an electrolyte% to add The electrolyte solution that needs to be replenished in the container 14. The shunt tube 24 is connected to a shunt pump (filter, filter) 30 outside the container 14; and the shunt pump (filter filter) 30 is further connected to the inlet line 32 of a storage tank to Storage tank 34 filled with electrolyte. Next, storage tank 34 filled with electrolyte is connected to the container 14 through the outlet line of a storage tank. Among various possible systems to which the present invention is applicable, the above-mentioned electrochemical plating (ECP) system 10 is only one example, and these designs can be changed, and other systems can also be replaced. The f-process of the present invention enables the modulation mode of the Wake-Electric Hull Solution 2Q, such as copper, Shao, nickel, chromium, zinc, Gold, silver, lead and cadmium Plating liquid. The present invention is also suitable for using a plating liquid containing a metal mixture and an electron microscope on a substrate. The electric clock liquid 20 is preferably a copper alloy plating liquid, and more preferably a copper electric clock liquid.-Generally speaking, the copper plating liquid Modulation can be performed using known methods of the prior art ', but is not limited to sulf ^ ric acid, acetic acid, fluoroboricacid, metanlansulfonicacid, ethanesulfutenic acid (Ettlane sulfonic acid), Sulfonic (phenyl sulfonic acid) 'methyl sulfonic acid, p-toluene sulfonic acid

0503-A31535TWF 10 200540145 (p-tolixenesiilfonic acid) ’Hydrochloric acid, phosphoric acid Temple. These acids are mainly present in liquids with an agronomic range ranging from about 1 to 300 grams per liter (g / L). These acids also include sources of dental ions, such as chloride ions. Suitable sources of copper ions include, but are not limited to, copper sulfate, copper chloride, copper acetate, copper nitrate, copper fluate and copper fluoride. rate), copper methane sulfonate, copper phenyi suifonate, and copper p-toluenesuifonate. These copper ion sources are mainly present in the liquid as a plating solution having a concentration ranging from about 10 to 300 grams (g / L) per liter. Referring to FIG. 1A, FIG. 1B, and FIG. 2, according to the method of the present invention, a metal seed layer 19, such as copper, is deposited on a wafer substrate 18, as shown in steps in FIG. According to the known method of the prior uranium technology, the metal seed layer 19 may be deposited on the wafer substrate 18 by a conventional chemical vapor deposition (CVD) or physical vapor deposition (PVD) technology. The thickness of the metal seed layer 19 is mainly about 50 to 1500 Angstroms (A). As shown in step S2 in FIG. 2, an electrochemical plating (BQp) electrolyte liquid solution 20 is prepared in a container 14. Next, as shown in step S3, the organic synthetic mixture shown in the present invention is prepared; then, a liquid-layered composite suspension layer 26 is suspended on the liquid solution 20. The anode 16 and the substrate 18 are immersed in the liquid experience 20 'and the thallium wire 38 is connected to the adjustable Wei current source 12. 1. Referring to FIG. 1B and as shown in step S4 in FIG. 2 ', the substrate 18 is passed through the composite suspension layer 26: and then charged into the liquid cold liquid 20. Considering Fig. 1B, the seed layer on the substrate 18 contacts the composite suspension layer 26, which causes the wet layer 26a to break the suspension layer of the composition and adhere to the surface of the seed layer π. During the subsequent electroplating process, the wetting layer 26 a remains on the seed layer 19. The technology of the present invention will promote the wettability of the seed layer 19 in the electrochemical liquid (EC?) Electrolyte liquid solution 20 with the wet layer 26a during the electric clock process.

In step S5 in the figure, a metal layer (not edged out) is then electrically bonded to the seed layer. In the operation of the electrochemical clock (ECP) system 10, the current source 12 provides a predetermined electrical operation between the anode M and the cathode (substrate) 18 to operate at temperatures. The electric waste potential establishes a magnetic field between the anode μ and the cathode (base 0503-A31535TWF 11 200540145) 18, and the magnetic field will affect the standard copper electroplating financial solution of liquid solutions such as internal copper ions, about 2 volts (read) radio Run for about 2 minutes, and about 4 amperes (current flows through the anode) 6 and the cathode (substrate) 18. Then, when the electrons leave from the steel anode! 6, the copper is oxidized at the oxidation surface 22 of the anode 16, And the copper sulfate solution in the container, such as the reduction of copper ions, causes it to form at the interface between the cathode (substrate) 18 and the copper sulfate liquid-electrical copper (not edged out). By promoting the entire surface of the seed layer 19 As the copper sulfate liquid is uniformly wet-dispensed, the wet layer 26a helps to clock a continuous metal layer on the seed layer 19, substantially avoiding structural defects such as pits. Therefore, the electric metal layer on the substrate 18 provides Integrated Circuit (IC) • The device is manufactured with structural and operational integrity. Refer to the numerical schematic diagram in Figure 3 to indicate the contact angle of the Electrolyte Clock (Ecp) electrolyte liquid solution on the seed layer. Invention composition and method After treatment, its value: 20%. Compared with the seed layer of the control group, its contact angle is about 30 ~ 3S%, and its seed layer is not treated before the electric clock process. Therefore, the seed layer is _ Metal solids to avoid and other structural defects, which will reduce the quality of integrated circuit (IC) devices manufactured by electroplated metal layers. Although the preferred embodiment of the present invention is proposed above, it can be done in the present invention Various modifications; the scope of the attached patents covers all modifications without departing from the spirit and scope of the invention. ^

0503-A31535TWF 12 200540145 [Brief description of the drawings] The content of the present invention is described here, and it is made by means of diagrams and flow diagrams ~ Goming Figure 1A is a schematic diagram of the electrochemical plating system completed by the present invention. Figure 1B is the surface-a side view of the base. The county's bottom through the electroplating electrolyte in the composite mixed floating layer, the seed layer on the substrate to form a composite mixture

Figure 2 is a schematic diagram of the process, indicating the completion of the process steps of the present invention. Figure 3 is a schematic diagram of numerical probabilities. The contact angle (γ axis) is tested against the Q-time (X axis) relationship. The contact time in the clothing process is 1 hour, and the miscellaneous forehead with Lai is in the seed layer. [Key component symbol description] 2 ~ an adjustable current source; 16 ~ copper anode; 38 ~ wire; 30 ~ shunt pump (filter Device); 32 ~ inlet pipeline; 19 ~ metal seed layer; 2 such as ~ wet layer. 10 ~ electrochemical plating (ECP) system · 14 ~ container; 18 ~ cathode; 24 ~ shunt filter conduit; 34 ~ storage tank with electrolyte; 36 ~ outlet pipeline; 26 ~ composite suspension layer;

0503-A31535TWF 13

Claims (1)

200540145 10. Scope of patent application: 1. An electrolytic solution for copper electroplating, including an electrolyte solution; and-a composite containing an organic acid and a non-ionic polymer mixed with the organic acid in the electrolyte solution . 2. The electrolytic solution for copper electroplating as described in item i of the scope of patent application, wherein the organic acid is citric acid or acetic acid. 3. But as described in item 1 of the scope of patent application Electrolytic solution for copper electroplating, wherein the non-ionic polymerization system includes alcoxol (alcohol alkoxylate), alkoxylate (alkoxylate) or aikoxyphenol (alkoxylate) ). 4. The electrolytic solution for copper electroplating as described in item 1 of the scope of patent application, wherein the composition is dissolved in the electrolyte solution at a concentration of about five percent (5%) by weight. The electrolytic solution for copper electroplating according to item 1 in the range, wherein the molecular weight of the non-ionic polymer is less than 1000. 6_ The electrolytic solution for copper electroplating according to item 5 in the patent application range, wherein the organic acid is citric acid ( citric acid) or acetic acid. φ 7. The electrolytic solution for copper electroplating as described in item 1 of the scope of patent application, wherein the organic acid is present in the concentration of about ten percent (10%) by weight. Within the composition; and the non-ionic polymer About five percent (5%) is present in the composition. 8_ The electrolytic solution for copper electroplating as described in item 7 of the scope of patent application, wherein the organic acid is citric acid or acetic acid acid); and the non-ionic polymer-based alcohol alkoxylate, amine alkoxylate or alkyphenol alkoxylate. 9. An electrolytic solution for copper electroplating, comprising : An electrolyte solution; and a composite containing an organic acid and a non-ionic polymer, which is mixed with the organic acid in a suspension layer of the 0503-A31535TWF 14 200540145 electrolyte solution. The electrolytic solution for copper electroplating, wherein the organic acid is citric acid or acetic acid. 11. The electrolytic solution for copper electroplating according to item 9 of the patent application scope, wherein the non-ionic polymer It is aleohol alkoxylate, aikoxyiate or alkyphenol alkoxylate. 12. The electrolytic solution for copper electroplating as described in item η of the patent application range, wherein the composition is dissolved in the electrolyte solution at a concentration-to-weight ratio of about five percent (5%). 13. The electrolytic solution for copper electroplating according to item 9 of the scope of the patent application, wherein the organic acid is present in the composition in a roll weight ratio of about ten percent (10%); and the non-ionic polymer system It is present in the composition in a concentration-to-weight ratio of about five percent (5%). 14. The electrolytic solution for copper electroplating according to item 13 of the scope of the patent application, wherein the organic acid is citric acid or acetic acid. 15. The electrolytic solution for copper electroplating according to item 13 of the scope of the patent application, wherein the non-ionic polymer is an alcohol alkoxylate, an aminealkoxylate or an oxyalkoxylate. Age (alkyphenol alkoxylate). 16. The electrolytic solution for copper electroplating according to item 15 of the scope of the patent application, wherein the organic acid is citric acid or acetic acid. 17. A method of electroplating a metal onto a surface to be electroplated in an electroplating electrolyte, including providing a synthetic mixture including an organic acid and a non-ionic polymer; forming the electroplating electrolyte solution in the electroplating electrolyte solution; Synthesize a suspension layer of the mixture; it is formed by the method of entering the surface of the to-be-mirror through the suspension layer into the solution, and forming a gate layer on the to-be-plated surface; and electroforging the metal to the to-be-plated surface; Electric clock on the surface. 18. The method for electroplating a metal to a 0503-A31535TWF 15 200540145 in a plating electrolyte as described in item 17 of the scope of patent application, wherein the organic acid is citricacid or acetic acid ); And the non-ionic polymer-based alkoxylated alcohol (alcoh; lykoxyiate), alkoxylated amine (amnie alkoxylate), or alkoxylated phenol (alkyphenoi alkoxyxate). 19. The method of electroplating a metal onto a surface of a bell in an electroplating electrolyte as described in item 17 of the scope of patent application, wherein the organic acid is about ten percent (10%) in a concentration by weight ratio. It is present in the synthesis; and the polymer is present in the composition in a concentration-to-weight ratio of about one hundred. 20. As described in the application for patents | _ 17 of the in-plating electrical post electroplating _ material to wire surface office-substrate ^ metal seed layer 0503-A31535TWF 16