TW200426949A - Multi-anneal process - Google Patents

Abstract

A multi-anneal process is disclosed. The present invention comprises: providing a substrate; forming a copper film on the substrate; and proceeding with a plurality of anneal steps to the substrate. Moreover, the aforementioned plurality of anneal steps comprises a first anneal step and a second anneal step proceeded sequentially, wherein the temperature and time of the first anneal step are 50 DEG C to 400 DEG C and 10 seconds to 1000 seconds respectively; and the temperature and time of the second anneal step are 100 DEG C to 500 DEG C and 1 minute to 10 hours respectively.

Description

200426949 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a multi-anneal process', and particularly to a multi-anneal process suitable for a semiconductor copper process. [Previous technology] In the case that traditional aluminum metal wires cannot break through the bottleneck, after years of research and development, copper wires have become the mainstream of semiconductor materials. Because copper has a smaller resistance than aluminum, it can carry a larger current in a smaller area, allowing manufacturers to produce faster, denser circuits, and improve performance by about 30% to 40%. In addition, since copper has better resistance to Electro-migration than aluminum, it can reduce its electromigration function and thus improve the reliability of the two wafers. Please refer to the flow chart of the conventional copper process with a single annealing step shown in Figure 1. First, a substrate is provided, wherein the substrate has been formed into a part of a semiconductor device in a previous process. Next, as shown in step 10, a copper film is formed on the substrate, where the copper film can be a via layer and a metal layer (or a contact layer and a metal layer) in a dual damascene process, and this step 丨〇 This can be achieved by, for example, Electrochemical Plating (ECP). = After the copper film forming step is completed, the copper film is still unstable. Therefore, a heat treatment process must be applied to the copper film to stabilize the crystal grain growth of the copper film. Therefore, it is necessary to perform an annealing step on the above substrate with a copper film as shown in step 20, where the annealing step is generally performed in the same reaction chamber as described in the electrochemical reaction process described above. ^ Proceed. Then, as described in step 40, the surface of the copper film is subjected to chemical mechanical research.

Page 5 C > Λ 200426949 V. Description of the invention (2) Polishing (Chemical Mechanical Polishing; CMP), in order to achieve the required flatness of the surface of the copper film. Currently, the copper process with step 20 in the first figure above has become a standard process. However, although the copper process shown in Fig. 1 can make the copper film have the required anti-electron migration ability, as far as the stress migration phenomenon of the copper film is concerned, the copper process shown in Fig. 1 has The stress migration phenomenon of the copper film cannot be suppressed smoothly, which leads to an increase in the interlayer resistance and a decrease in the yield in the stress migration test. Therefore, it is necessary to find a solution. [Summary of the Invention] Therefore, the purpose of the present invention is to reduce stress migration. Another object of the present invention is to improve the yield of the other object of the present invention in the low stress migration test and to stabilize it. First, a substrate is provided to perform a plurality of withdrawals on the substrate, including sequentially performing the first annealing step of 1000 seconds, and the second withdrawal C and 1 minute to 10 hours. In addition to temperature and time, it is to provide a multiple annealing process, which can be used | It is to provide a multiple annealing process, which can reduce the increase rate of the dielectric resistance. This is to provide a multiple annealing process, which can be used to make it. Objective To propose a multiple annealing process. In the present invention, the multiple annealing process includes at least the following steps. . Next, a steel film is formed to cover the substrate. Then, fire steps. In addition, from the above several annealing steps to a first annealing step and a second annealing step, the temperature and time of the temperature and time are respectively 50 ° to 400 ° and the time from the second step to the fire step are 1 〇〇〇c ～ 500。 In addition, the first annealing step and the second annealing step are as described above, in a preferred embodiment of the present invention

200426949 5. In the description of the invention (3), the temperature of the first annealing step may be lower than that of the second annealing step; and the time of the first annealing step may be shorter than that of the second annealing step. Furthermore, the first annealing step and the second annealing step further include cooling the substrate to room temperature. Therefore, applying the present invention can reduce the phenomenon of stress migration. In addition, the application of this volume can reduce the increase rate of the stress migration test intermediary. Furthermore, the application of the present invention can improve the yield and be more stable. [Embodiment] The present invention relates to a multiple annealing process suitable for a semiconductor copper process. Please refer to the flow chart of the steel process with multiple annealing steps according to the present invention shown in FIG. 2. First, a substrate is provided: this substrate: a semiconductor structure has been formed in a previous process. Next, as shown in step 110, the interlayer and metal layer (or contact layer and metal layer) of ^ ;, and this step 110 can be, for example, electrochemical, and then, as shown in step 120, the pair is achieved. The fire step, ▲ in this first i fire step, the copper base material is the same as the first refund-in the reaction chamber == one: the temperature and time required for the electrochemical step ; The first-annealing of this step 120 for 1,000 seconds. For example, each may be 50. 〇 to 400 t and 10 seconds to then, let the temperature of the above substrate drop, ^ ^ The process of warming can also continue with the temperature of this substrate dropped to the room for the first genre / cattle Into /, or to move the substrate out of the reaction chamber of the < brother annealing step. 200426949

Next, as in step U η-the second step of this step 130 =, the second annealing step is performed on the substrate, which is 100 ° c to 5 0 0 1 = the temperature and time required for the fire step can be used separately Fang Φ minutes to 10 hours. As for the second annealing step, the hot plate (Hot P1 is better than the above steps and the temperature and time of the second annealing step may be lower than the second temperature). In the preferred embodiment, 'f -The temperature of the annealing step may be less than the temperature of the second annealing step; and the time of the second annealing step of the second annealing step is a feature of the present invention. Therefore, the first annealing step can reduce the stress in the copper film. The migration phenomenon is mentioned as the increase rate of the interlayer resistance in the j-low stress migration test, and can be used as the rate. However, the invention is not limited to using only two annealing steps 7 to 7 to form a copper film on the substrate. Then, at least two annealing processes are performed, all of which are within the scope of protection. That is, the present invention can be added to the single-annealing process only after the standard single-annealing process shown in Figure 2, or in: ί: — At least two additional annealing systems are added after the annealing process, which are all within the protection scope of the present invention. As shown in step 140, chemical mechanical research is performed on the surface of the steel film to achieve the desired surface of the copper film. Required flatness. Then, grind, borrow

Please refer to the diagram of the relationship between the T-layer resistance offset and the probability of occurrence of the multiple annealing process of the present invention, the conventional standard annealing process, and the single annealing process to increase the thermal budget shown in FIG. 3. As described above, the multiple annealing process of this embodiment can effectively suppress the stress migration phenomenon in the copper film, thereby reducing the increase in the interlayer resistance caused by the long-term stress migration. From Figure 3

200426949 V. Description of the Invention (5)-This effect of the present invention can be clearly seen. Corresponding data of the multi-annealing process of the invention; the display = the corresponding data of the process; and the legend c indicates; once === early; earthenware: 1 should data 'where the increase in thermal premise corresponding to this legend c =: 2 The total annealing energy of the fire process corresponds to Figure A; the total annealing energy of the fire process is approximately equal. As for ^ 之 夕 ’s regressive interlayer resistance offset (unit An, and the horizontal coordinate in the figure in the figure is Yetian, the early position is magic and the vertical coordinate is a certain medium # 雷 阳 推;: Probability (unit:%). In addition, the data in Figure 3 / Kelvin single-media acoustic measurement 1 commonly used in the industry of needle-biased conductors is based on the measurement of + into Luhan and Libi. + Early 7 丨 Thickness measurement δ The structure is obtained by performing a 100-hour private quasi-stress migration test. The multiple annealing process represented by a has the best performance η :: Example · Lightning resistance value sheep illustration AK Dielectric current of the multiple annealing process The P offset is approximately 10% lower than the offset resistance of the interlayer resistance represented by Fig. B and Fig. C. The multiple annealing steps of the present invention are illustrated in Fig. 4 with reference to Fig. 4 The yield rate of the annealing process is better than that of the sea bass. The 4th prince and the standard of good hands are compared. Figure 4 shows the yield rates of the Qiantai Lu ηη heavy annealing process and the conventional standard single annealing process. : Not as much as the present invention, each quasi-early annealing process has a large variation of white ^ knife cloth, and the multiple annealing system of the present invention 49 shoulders, and the multiple annealing process of the present invention has a yield rate of about this wool month. The multiple annealing process can increase the yield rate by at least about 10% compared with the conventional fire process. Therefore, the present invention: a car with a high yield rate. ^ It is only stable for k. Page 9 200426949 V. Description of the invention (6) From the above-mentioned preferred embodiments of the present invention, it can be seen that the application of the present invention can be used to migrate. XI should also be better implemented by the above-mentioned present invention It can be known from the examples that the application of the present invention reduces the increase rate of the interlayer resistance in the stress migration test. 9) Furthermore, from the above-mentioned preferred embodiments of the present invention, it can be seen that the application of the present invention improves the yield and is relatively stable. G Although the present invention has been A preferred embodiment is disclosed as above, but its combination = invention. Anyone who is familiar with this technique, without departing from the present invention, can make various modifications and retouches in the car loop. Therefore, the mouth of the present invention should be attached as a watch. The definition of the scope of patent application shall prevail.

Page 10 200426949 Brief Description of Drawings Figure 1 shows the flow chart of a conventional copper process with a single annealing step. FIG. 2 is a flowchart of a copper process with multiple annealing steps according to the preferred embodiment of the present invention. FIG. 3 is a graph showing the relationship between the interlayer resistance offset—the amount and the occurrence probability—of the multiple annealing process of the present invention, the conventional standard single annealing process, and the single annealing process to increase the thermal budget. FIG. 4 is a comparison chart of yields of the multiple annealing process of the present invention and the conventional standard single annealing process. [Simple description of the element representative symbols] 10 ·· Forming a steel film on the substrate 20: Performing annealing step 40: Performing chemical mechanical polishing 110: Forming a steel film on the substrate 120: Performing the first annealing step 130: Performing the second annealing Step 140: Chemical mechanical polishing A: Multiple annealing process B: Standard single annealing process C k Single annealing process with thermal budget j

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Claims (1)

200426949 6. Scope of patent application 1. A multi-anneal process includes at least: providing a substrate; forming a copper film to cover the substrate; and performing a plurality of annealing steps on the substrate. 2 · The multiple annealing process as described in item 1 of the scope of the patent application, wherein the step of forming the copper film is performed using electrochemical plating (ECP) 〇 3 · Multiple annealing as described in the scope of the patent application in item 1 In the manufacturing process, the annealing steps include at least one first annealing step and one second annealing step in sequence. 4. The multiple annealing process according to item 3 of the scope of patent application, wherein the temperature of the first annealing step is 50 ° C to 400 ° C. 5. The multiple annealing process as described in item 3 of the scope of the patent application, wherein the time of the first annealing step is 10 seconds to 1000 seconds. 6. The multiple annealing process according to item 3 of the scope of the patent application, wherein the temperature of the second annealing step is 100 1 to 50 ° C. 7. The multiple annealing process described in item 3 of the Shishen 5 Qing patent scope, wherein the time of the first annealing step is 1 minute to 0 hours. Page 12 200426949 VI. Patent application scope 1-1 ^ 8 · The multiple annealing process as described in item 3 of the patent application scope, wherein the first annealing step and the second annealing step further include cooling the substrate To a room temperature. 9. The multiple annealing process as described in item 3 of the scope of patent application, wherein the second annealing step uses a hot plate. 10. The multiple annealing process according to item 3 of the scope of the patent application, wherein the temperature of the first annealing step is lower than the temperature of the second annealing step. 11. The multiple annealing process according to item 3 of the scope of patent application, wherein the time of the first annealing step is less than the time of the second annealing step. 12. The multiple annealing process as described in item 1 of the scope of the patent application, wherein the annealing steps further include a chemical mechanical polishing (CMP) step on the substrate. 13. A multiple annealing process, at least comprising: providing a substrate; forming a copper film to cover the substrate; performing a first annealing step on the substrate; and performing a second annealing step on the substrate. Page 13 C η 200426949 VI. Scope of patent application 1 4 · The multiple annealing process as described in item 13 of the scope of patent application, wherein the step of forming the steel film uses an electrochemical bond. 15. The multiple annealing process described in item 13 of the scope of the patent application, wherein the temperature of the first annealing step is 50 °. (： 400 ° C ° 16 · The multiple annealing process as described in item 3 of the patent application scope, wherein the time of the first annealing step is from 0 seconds to 1000 seconds. 1 7 · As applied The multiple annealing process described in item 13 of the patent scope, wherein the temperature of the second annealing step is from 1000 to 500 ° C. 18. The multiple annealing process described in item 13 of the patent application scope, wherein the first The time of the second annealing step is 1 minute to 10 hours. 19. The multiple annealing process as described in item 13 of the scope of the patent application, wherein the first annealing step and the second annealing step further include cooling the substrate to form 1 room temperature. 20. The multiple annealing process described in item 13 of the scope of patent application, wherein the second annealing step uses a hot pad. 21. The multiple annealing process described in item 13 of the scope of patent application, The temperature of the first annealing step is lower than the temperature of the second annealing step. Page 14 200426949 6. Scope of patent application 22. The multiple annealing process described in item 13 of the scope of patent application, wherein the time of the first annealing step is less than the time of the second annealing step. 23. The multiple annealing process as described in item 13 of the scope of patent application, wherein the second annealing step further includes a chemical mechanical polishing step of the substrate I I Page 15