TW201012976A - Method for substantially uniform copper deposition onto semiconductor wafer - Google Patents

Abstract

The methods practiced in an electrochemical deposition apparatus with two or more electrodes, described in earlier inventions, are disclosed. The methods produce uniform copper films with WFNU less than 2.5% on semiconductor wafers bearing a resistive copper seed layer with a thickness ranging from 50 to 900 Å in a copper sulfate based electrolyte whose conductivity is between 0.02 to 0.8S/cm.

Description

201012976 VI. INSTRUCTIONS: [Related patent citation] This patent application is a continuation of the U.S. patent filed on Jan. 15, 1999 (patent application number 09/232,864, patent number 6391 166). U.S. Patent No. 6,391,166 issued to U.S. Patent Application Serial No. 60/074,466, filed on Feb. 12, 1998, and U.S. Patent Application Serial No. interest. At the same time, this application also declares the benefits of the international patent number PCT/CN2007/071008 filed on November 2, 2007. All of the above patents are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to a method of electrochemical deposition in the fabrication of ultra-large integrated circuits to produce a uniform copper film on an ultra-thin, large-impedance seed layer semiconductor workpiece. [Prior Art] Electro-crystals and interconnect elements are fabricated using a number of different processing steps on a semiconductor wafer. In the process of forming the interconnection elements, the semiconductor wafer may be subjected to treatment such as, for example, masking, etching, and deposition to form a semiconductor transistor and a desired electronic circuit to connect the terminals. Specifically. Multiple masks, ion implantation annealing and plasma etching, and chemical and physical vapor deposition steps can be performed to form narrow trenches, transistor well gates, polysilicon lines, and interconnect structures such as vias and trenches. . 3 201012976 • After the formation of vias and trenches, a conductive material is deposited in these structures to connect the transistors at the bottom. Excess conductive material is removed to form the conductive structure to form the desired circuitry. In the manufacture of ultra-large integrated circuits, a metal film layer is electrochemically deposited on an ultra-thin large resist seed layer to form a conductive line, which is usually a copper film. This deposition process can fill the via structure' trench structure or a hybrid structure of the two structures. When these structures are filled, copper is continuously deposited and a film is formed on the surface of the semiconductor wafer. The uniformity of the copper film that is ultimately formed by φ is critical because the subsequent process steps to remove excess copper (usually the planarization step CMP) require high uniformity, resulting in a final output between the device and the device. Get the same electrical performance. Advanced process technology generally controls the in-film heterogeneity (wFNU, which is the ratio of the film thickness standard deviation to the average film thickness) within 2.5%. The large WFNU has a negative impact on subsequent CMP process steps and will cause localized copper residues or excessive dielectric material loss during the copper throwing process. If the polishing process removes the copper on the wafer an equal amount, the original copper film at the edge of the wafer is relatively thicker than ®, causing copper or barrier layers to remain there. This incomplete removal process will cause the device to be shorted. If the polishing is used to remove the copper and barrier layers at the edge of the wafer, the dielectric material in the vicinity of the center of the wafer is excessively lost 'the height of the trenches and vias is lowered, and the resistance between the interconnects on the wafer is different. Both effects are very detrimental to the yield of the device. In order to meet the ever-increasing development of manufacturing technology, the wafer size has changed from 200 mm to 300 ram, and the thickness of the seed layer has continued to decrease, so that the ohmic resistance of the seed layer on the semiconductor wafer is significantly increased. In conventional electrochemical deposition processes (generally referred to as electroplating), the power supply supplies current or voltage to a single working electrode and a wafer substrate with a seed layer of 201012976. The wafer substrate, working electrode, power source and electrolyte form an electrolytic cell. Due to a phenomenon called "edge effect", the current density on an ultra-thin large-impedance wafer is not uniform and is relatively high at the edges. This current non-uniformity causes the plating rate to be high at the edge of the wafer and the center of the wafer to be low, thereby causing uneven thickness of the copper film deposited on the surface of the wafer. When the seed layer thickness is reduced and the wafer size is increased, the edge effect is more pronounced. In the most severe cases, deposition occurs only at the edge of the wafer.边缘 Edge effects can be improved by using a relatively low acid electrolyte, as shown in Figures 3a-3d. However, with the development of technology, it is still impossible to solve the uneven plating caused by the edge effect by using only a low acid electrolyte. Generally, this non-uniformity can be improved by increasing the thickness of the coating, as shown in Figures 3c-3d. However, this will severely limit the capacity of process equipment and greatly increase the cost of removing excess material from subsequent flat chemicals. In the existing patents, many designs have been applied to process equipment to solve the problem of unevenness caused by edge effects. U.S. Patent No. 6,391,166 (1999.1.15) discloses an electroplating apparatus and method that employs an independent power supply control electrode system to overcome the problem of uneven plating rates on the ultrathin seed layer of semiconductor wafers. U.S. Patent 6,575,954 (2004, 2.9) discloses an electroplating apparatus and method for electrodepositing a copper film which provides a relatively small film thickness deviation, in one of the embodiments 'on a 300 mm wafer having a 400A seed layer The thickness deviation of the copper film obtained by depositing 〇.6um (6000A) copper film was 394A. 5 201012976 SUMMARY OF THE INVENTION The present invention discloses a method for an electrochemical deposition apparatus having multiple electrodes and a power supply control system. In the text and illustration of the present invention, the device is referred to as the device. An embodiment of the apparatus is described in U.S. Patent No. 6,391,166 and the entire disclosure of PCT/CN2007/071 008. The disclosed method is applied to wafer plating having a seed layer thickness of 5 Å to 900 Å, and the conductivity of the electrolyte used is 〇 2 0.8 2 to 0.8 s / cm. _ The disclosed method can prepare an electrochemical clock copper film with a wafer inhomogeneity of only 0.33% (thickness deviation of 42A) on a wafer having a 35〇A seed layer, which is less uneven than the method disclosed in the prior patent. Several times. [Embodiment] The present invention discloses a method for an electrochemical deposition apparatus having a multi-electrode and a power supply control system. The disclosed method is applied to wafer plating having a thickness of 50 ° to 90 0 A, and the conductivity of the electrolyte used is 0·〇2 to 〇·8 S/cm. This method will be implemented in the apparatus disclosed in U.S. Patent No. 6,391,166. The method of the present invention comprises the steps of: injecting an electrolyte into the apparatus at a flow rate in the range of 1 to 20 LPM; transferring the wafer to the wafer holding device - the device is electrically conductive from the wafer; applying a small bias to the wafer The wafer is sent to the electrolyte 'and the front surface of the wafer is in full contact with the electrolyte 6 201012976; current is supplied to each electrode; each power source connected to each electrode can be switched from voltage mode to current mode at the required time Provide a relatively small current or voltage to each electrode, the total current is preferably 2A to 10A, and the current density ratio between the electrodes is 〇. 5: 丨 to 300:1; provide a relative to each electrode a large current or voltage, the total current φ is preferably 10A to 40A, and the current density ratio between the electrodes is 0.5:1 to 300:1; switching to a small bias mode is applied to the semiconductor wafer; Take the wafer out of the electrolyte; stop the power supply' and remove residual electrolyte from the wafer surface. In the sixth step and the seventh step described above, the current distribution on each electrode and the current density ratio between the electrodes were varied within a small range depending on the number of electrodes used and the electrolyte conductivity. In the following examples, these ranges will be specifically described for the specific number of electrodes and electrolyte conductivity. In one embodiment, a method of applying the two-electrode device is disclosed, wherein the electrolyte conductivity is 0.0 2-0. 2 S/cm. </ RTI> In one embodiment, a method of applying the two-electrode device is disclosed. In one embodiment, a method of applying to the three-electrode device is disclosed wherein the electrolyte conductivity employed is 002_0·2 s/cm. </ RTI> In one embodiment, an electrolyte is used in the three-electrode device. In an embodiment, a method of applying the electrolyte to the four-electrode device is disclosed in which the conductivity of the electrolyte is 0.0 2-0. 2 S/cm. In one embodiment, a method of applying the electrolyte to the four-electrode device is disclosed in which the electrolyte conductivity is 0.2-0. 8 S/cm. In one embodiment, 'a method of applying to the ten-electrode device' is disclosed in which the electrolyte conductivity is 〇〇2_〇 2s/cjn. </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> Figure 2 depicts a conventional electroplating apparatus having a single electrode 2〇1. Figures 3a-3d show the deposition curves obtained on the surface of a 3 mm semiconductor wafer using this single electrode plating apparatus. Specifically, Figures 3a-3b illustrate deposition curves of a 3〇〇〇A thick copper film deposited on a semiconductor wafer having a thickness of 350A to 900A, using low conductivity and high conductivity electrolytes, respectively. . Figures 3c-3d illustrate the deposition curves of a 3000A to 6000A thick copper film deposited on a semiconductor wafer with a 350A seed layer, using a low conductivity and high conductivity electrolyte, respectively, as shown in Figures 3a-3b The WFNU values calculated from the thickness curves are listed in Table 1. The WFNU value increases as the thickness of the seed layer decreases, indicating that it is difficult to uniformly deposit a copper film on the surface of the semiconductor wafer when the enamel layer is thin. The WFNU value is less than 2.5% when the thickness of the enamel layer is less than 700 Å. The situation is even worse when the electrolyte conductivity increases. 201012976 Table 1 Seed layer thickness Low conductivity Electrolyte high conductivity electrolyte - WFNU -WFNU 350A 3. 72% 13.91% 550A 2. 95% 11.45% 700A 2. 58% 10.19% 900A 2.21% 8. 94% As shown in Figures 3c-3d, WFNU is improved as the thickness of the plated layer increases over the same 350A seed layer. The corresponding values are listed in Table 2. This phenomenon is due to the reduced ohmic resistance of the thickened film during deposition, which reduces the edge effect. In the case where the plating thickness is less than 5000 A, the WFNU value is more than 2.5%, and when the conductivity of the electrolyte is high, the WFNU value is much larger than 2.5%. Although increasing the plating thickness improves WFNU, the subsequent CMP steps in the 1C process require high cost to remove excess copper film, which does not allow the deposited film to be too thick. Table 2 Deposition Thickness Low Conductivity Electrolyte High Conductivity Electrolyte - WFNU -WFNU 3000A 3. 72% 13·91% 4000A 2. 98% 11.25% 5000A 2. 48% 9. 93% 6000A 2. 12% 8. 83% 9 201012976 All analyses of the present invention are based on a thinner seed layer (35〇A) and a plating thickness (3000A), such a combination making the disclosed method highly sensitive. [Embodiment 1] In one embodiment of the present invention, a method of depositing a copper film on a semiconductor wafer applied to the apparatus shown in Fig. 4 is disclosed. The device is a diagram

An embodiment of the invention comprising a first electrode 401a and a second electrode 4〇1b, wherein the first electrode area is 50%-90% of the total electrode area, and the ratio of the total electrode area to the semiconductor wafer area is greater than 〇85 . The method comprises the following steps: Step 1: Opening the fluid control devices 4233 and 423b to control the flow rate of each electrode working region 'in the working region of the first electrode 4Gla' flow rate is 5 to 20 LPM, at the second electrode 4 () In the working area of 11), the flow rate is 1 to H5 LPM. In one embodiment of the present invention, the devices 423a and 423b are opened when the door is raised, and in another embodiment of the invention, the flow control devices 423a and 423b are opened at different times. The semiconductor wafer of the crystal layer is electrically conductive to the crystal of the wealth; the seed layer of the flat conductor is contacted by the seed layer: step 3: applying a 0.01-10V to the semiconductor wafer of the semiconductor wafer; 4: using the wafer holding device 曰&amp; hair to send the sun piece to the electrolyte, and the front surface of the ruthenium film is completely immersed in the electrolyte on the 4th; sub 4 step 5: to the electrode 4〇la盥〃 401b &amp; Current, and keep ^ 10 201012976 The voltage on the pole 40 la is positive, the voltage on the electrode 40 lb is positive or negative (the sign of the voltage in this paper is relative to the wafer); the working current of the electrode 401 a is 5 to 20A, the electrode 401b The operating current is 0.01 to 10A. The current density ratio on the electrodes 401a and 401b is 1:1 to 300:1. This step lasts 5 to 30 seconds to fill the vias and trenches on the surface of the semiconductor wafer 422. In one embodiment of the invention, the power supplies connected to electrodes 401a and 401b are simultaneously switched from voltage mode to current mode; in another embodiment of the invention, 'the power source connected to electrodes 401a and 401b is Switching from voltage mode to current mode at different times; Step 6: Supply current to electrodes 401a and 40 lb, and keep the voltage on electrode 401a positive, the voltage on 4〇lb is positive or negative; the operating current of electrode 4〇1&amp; For 15 to 40 A, the operating current of the electrode 401b is from on to 20A. The current density ratio on the electrodes 401a and 401b is ι:1 to 300:1. This step exerts a relatively large current on the electrodes 4〇1a and 4〇11}, thereby increasing the efficiency of electrochemical deposition. This step is terminated when the desired thick ruthenium film is deposited. Step 7 - Apply a small bias voltage to the semiconductor wafer. In one embodiment of the invention, electrodes 401a and 401b are simultaneously switched from a current mode to a voltage mode, and in another embodiment of the invention electrodes 401a and 40bb are switched from a current mode to a voltage mode at different times; The wafer is taken out from the electrolyte and rotated to remove residual electrolyte on the surface of the wafer. In steps 5 and 6, the positive and negative signs of the voltage of the electrode 401b are determined by the electrochemical connection. For example, when the conductivity of the electrolyte is low, the conductivity of the semiconductor wafer is low, the surface of the semiconductor wafer is thick, and the electrodes 401a and 401b are simultaneously applied with a positive voltage, as shown in FIG. 5a. When the conductivity of the electrolyte is high, the surface of the semiconductor wafer is thin, A positive voltage is applied to the electrode 401a, and a negative voltage is applied to the electrode 40 lb as shown in FIG. 5b. In step 5, the current density ratio and uniformity of each of the copper films are uniformly plated on a 300 mm semiconductor wafer having a seed layer of 200 to 2000 Å. The positive and negative sign of the electrode voltage, as shown in Table 3, the conductivity of the electrolyte used is 0. 02-0· 2S/cm and 0. 2-0. 8S/cm : Table 3 ..... - - - - - electrode 401a symbol electrode 401b symbol current density ratio (401a: 401b) conductivity 0. 02-0. 2S / cm + + 1:1-30:1 + - 15:1-30:1 - —2:1 二15_______ ❹ --- Plant 0. 2-0. 8S/cm After the thickness of the deposited copper film reaches 1500A, start step 6. The current density ratio and the positive and negative sign of each electrode voltage are uniformly plated on a 300 mm semiconductor wafer with a seed layer of 200 to 2000 A. The specific settings are as shown in Table 4. The conductivity of the electrolyte used is 〇. 0 2 -0. 2S/cm and 〇.2-0.8S/cm : 12 201012976 Table 4 Symbol 401b symbol current density ratio of electrode 401a (401a: 401b) Conductivity + + 1:1-30:1 0. 02-0 2S/cm + a 15:1-30:1 Conductivity 0. 2-0.8S/cm + a 10:1-20:1

Figures 6a and 6b illustrate the deposition curves of a 3000A thick steel film deposited on a 350A seed layer, using electrolytes of low conductivity and high conductivity, respectively. Among them, the curve of Method 1 is obtained by using the process parameters in Tables 3 and 4, and the curve of Method 2 is outside the range described in Tables 3 and 4. Obtained in the process parameters of Figures 6a-6b and Table 5. The WFNU values are shown in the table, and the disclosed method provides a large improvement in the surface of the 3_A film deposited by the high conductivity and low conductivity electrolyte. The field of the curve is deposited on the 3 〇〇 (4) semiconductor wafer, which is much more stringent than that used in the general industry. WFNU calculation excludes edge 2 3mm area excludes edge 3. 0 to 6· 5nm area meter

Method 1 (Revelation) - ___WFNU Low Conductivity Electrolyte High Conductivity Electrolyte

Method 2 (traditional) - WFNU 3. 65% 12.94% 13 201012976 In the case of the use of local conductivity and low conductivity electrolyte, the method is disclosed (method D is more traditional than method (method 2), making WFNU In the case of using a low conductivity electrolyte, the WFNU obtained is less than 2.5%. Embodiment 2 In one embodiment of the present invention, one is disclosed for use in FIG. 6 is a method for uniformly depositing a copper film on a semiconductor wafer. The device is an embodiment of the invention of FIG. 1, which comprises a first electrode 7a, a second electrode 701b, and a third electrode 7?lc, Wherein the first electrode area is 40%-60% of the total electrode area' ratio of the total electrode area to the semiconductor wafer area is greater than 0.85. The method comprises the following steps: Step 1: opening the fluid control devices 723a, 723b and 723c to control The flow rate of the working area of the parent electrode is 'in the working area of the first electrode, the flow rate is 5 to 20 LPM, and the flow rate in the working area® of the second electrode 701b is 5 to 20 LPM, in the working area of the third electrode 701c. Internal 'flow rate is 1 to 15 LPM. In this In one embodiment of the invention, the fluid control devices 723a, 723b and 723c are simultaneously opened, in another embodiment of the invention the 'fluid control devices 723a, 723b and 723c are opened at different times; Step 2: the transfer has a seed layer The semiconductor wafer is transferred to the wafer holding device 721 in the device. The device is in contact with the seed layer of the semiconductor wafer to conduct electricity. Step 3: Apply a small bias voltage to the semiconductor wafer, and the radius 14 201012976 is around 0. 01-10V; Step 4: Using a wafer holding device to send the wafer into the electrolyte and completely immersing the front surface of the wafer into the electrolyte; Step 5: supplying current to the electrodes 701a, 7〇lb and 7〇lc, and maintaining The voltages on the electrodes 701a and 701b are positive, the voltage on the electrode 7〇ic is positive or negative; the operating current of the electrode 701a is 2 to 20A, and the operating current of the electrode 701b is 〇·〇1 to 2〇A, and the operating current of the electrode is On φ to 20 A. The current density ratio on the electrodes 701a and 7〇lb is 1:1 to 50:1, and the current density ratio on the electrodes 70la and 701c is 1:1 to 3〇〇:1. 5 to 30 seconds, a through hole filling the surface of the semiconductor wafer 722 And a trench. In one embodiment of the invention, the power supply connected to the electrodes 7〇1 &amp; 701b and 701c is simultaneously switched from a voltage mode to a current mode; in another embodiment of the invention, the electrode 7〇la The power supplies connected to 701b and 701c are switched from the voltage mode to the current mode at different times; Step 6: supplying current to the electrodes 701a, 701b, and 701c, and maintaining the voltage on the electrodes 7〇la and 701b as positive, on the electrode 701c The voltage is positive or negative; the operating current of the electrode 701a is 4 to 30 A, the operating current of the electrode 701b is 4 to 30 A, and the operating current of the electrode 701c is 0.1 to 20 A. The current density ratio on the electrodes 701a and 701b is 1:1 to 50:1, and the current density ratio on the electrodes 7〇la and 701b is 1:1 to 300:1. This step applies a relatively large current to the electrodes 701a, 701b, and 701c, thereby improving the efficiency of electrochemical deposition. When the desired thick film is deposited, this step is terminated. Step 7: Apply a small bias voltage to the semiconductor wafer. At 15 201012976, electrodes 701a, 7〇lb, and 701c are simultaneously gas-extracted. In another embodiment of the invention, c is switched from current mode to step 8 at different times: the wafer is removed from the electrolyte, and the wafer surface remains removed by rotation. Electrolyte

In the above steps 5 and 6, the positive and negative signs of the voltage of the electrode 7〇lc are determined by the electrochemical deposition conditions. For example, when the conductivity of the electrolyte is low, the surface of the semiconductor wafer is electrically conductive, and the counter electrode 7〇la, 7〇 Lb* 7〇ic applies a positive voltage at the same time, as shown in Figure 8a; when the conductivity of the electrolyte is high, the conductive layer on the surface of the semiconductor wafer is thin, and a positive voltage is applied to the electrodes 7〇1 &amp; and 7〇lb, which is negative to the electrode 701c. The voltage is as shown in Fig. 8b. In step 5, the current density ratio and the positive and negative sign of each electrode voltage are uniformly plated on the 300 mm 2000 semiconductor wafer with a seed layer of 150 to 2000 A, as shown in Table 6. The electrolyte mode conductivity is used in one embodiment of the present invention. The current mode is switched to the voltage mode electrodes 701a, 701b, and 701. The voltage mode is 0. 02-0. 2S/cm and 〇·2-0. 8S /cm : Table 6 Electrode electrode current density ratio 701a of 701b of 701c (701a : (701a : symbol symbol 701b) 701c) Conductivity + + + 1:1-2:1 1:1-300:1 0.02 -0.2S/cm + + — 1:1-2:1 10:1-40:1 Conductivity + + - 5:1-20:1 2:1- 10:1 0.2-0. 8S/cm 16 201012976 When the thickness of the deposited copper film reaches 1500A, start step 6. The current density ratio and the positive and negative sign of the voltage of each electrode on the 300 mm semiconductor wafer of 50 to 2000 A· on the Xuan crystal layer are set as shown in Table 7. The conductivity of the electrolyte used is 0. 0 2-0. 2S/cm and 0.2-0.8S/cm : Electrode electrode electrode—symbol of symbol 701c of symbol 701b of current density ratio 701a (701a : 701b) (701a : 701c) Conductivity + + + 1:1-2:1 1:1-300:1 0. 02-0. 2S/cm + + a 1:1-2:1 50.1-300.1 Conductivity 0.2-〇. 8S/cm + + a 1: 1-2:1 ~~------ 20:1-80:1

Figures 9a and 9b illustrate the deposition curves of a 3〇〇〇A thick copper film deposited on a 350A seed layer. The (4) electrolytes are low conductivity and high conductivity electrolytes, respectively. The curve of Method 1 is that the curve of Method 2 in Table 6 and Table 7 is taken as the range outside the range described in Tables 6 and 7. The WFNU values are listed in Table 8. The method disclosed in Figures 9a-9b and Table 8 provides a significant improvement in the use of high conductivity and low conductivity electrolytes. The WFNU calculation of the deposition curve on the erased conductor wafer excludes the edge 2 3ffim area 17 201012976 domain ' This is much stricter than the usual industry, and the exclusion edge is used 3. 0 to 6. 5 mm area meter ❹

Low conductivity electrolyte high conductivity electrolyte

2. 81% 8. 55% using inter-conductivity and low-conductivity electrolytes, revealing methods, and more than traditional methods (method 2), make wFNU significantly good, especially in low conductivity 5%。 The WFNU is less than 2.5%. [Embodiment 3] In one embodiment of the present invention, a method of depositing a copper film on a semiconductor wafer applied to the apparatus shown in Fig. 1A is disclosed. The device is an embodiment of the invention of FIG. 1 and includes a first electrode 1001a, a second electrode 1001b, a second electrode i〇〇lc, and a fourth electrode, wherein the first electrode area is 30% of the total electrode area - 50 %, the ratio of the sum of all electrode areas to the area of the semiconductor wafer is greater than 0.85. The method comprises the following steps: Step 1: Opening the fluid control devices 13a, 23b, 1023c and 10 2 3d to control the flow rate of each electrode working region at the electrodes i〇〇ia, l〇〇lb and i〇 In the working area of 01c, the flow rate is 5 to 2 〇 lpm, and the flow rate is 1 to 15 LPM in the working area of the electric 18 201012976 pole 1 〇 01 d. In one embodiment of the invention, the 'fluid control devices i〇23a, 1 023b, 1 023c and 1 023d are simultaneously opened. In another embodiment of the invention, the fluid control devices 1023a, l23b, 1023c and l〇 23d is opened at different times; Step 2. Transfer the semiconductor wafer having the enamel layer to the wafer holding device 1021 in the device, and the device is in contact with the seed layer of the semiconductor wafer to conduct electricity; φ Step 3: The semiconductor wafer is applied with a small bias voltage ranging from 0.01 to 10 V. Step 4: The wafer holding device is used to send the wafer to the electrolyte, and the front surface of the wafer is completely immersed in the electrolyte; Step 5: To the electrode i 01a, i〇olb, i〇〇ic, and l〇〇ld provide current, and keep the voltages on electrodes 1〇〇la, 1〇〇113, and 1〇〇lc positive, and lOOld is positive or negative when energized; The operating current of iQoia is 1 to 15A'. The operating current of the electrode i〇〇ib is 〇5 to 1〇A, and the operating current of the electrode i〇〇lc ❹ is 〇〇1 to i〇A. The current density ratio of the electrodes i〇〇ia and i〇〇ib is 0.5:1 to 1〇:1, and the current density ratio of the electrodes 1〇〇1&amp; and i〇〇lc is 〇.5:1 to 50: 1. The current density ratio of the electrodes 1〇〇1&amp; and 1〇〇ld is 1:1 to 300: this step lasts 5 to 3 seconds, filling the vias and trenches of the surface of the semiconductor wafer 1 022. In one embodiment of the invention, the power supplies connected to the electrodes 10a, 1001b, 1〇01, and 1001 (1 are simultaneously switched from voltage mode to current mode; in another embodiment of the invention 'with electrodes L〇01a, 1001b, 1〇〇1 (: and 1001 (1 connected power supply switches from voltage mode to current mode at different times; 19 201012976 Step 6: To the electrodes l〇〇la, l〇〇lb, 1001c and L〇〇ld provides current and keeps the voltage on electrodes 1001a, 1001b and 1001c positive, the voltage on electrode 1001d is positive or negative; the operating current of electrode 1001a is 2 to 30A, and the operating current of electrode l〇〇lb is 1 to 30A, the operating current of the electrode 1001c is 1 to 30A, and the operating current of the electrode 100Id is 〇. 01 to 2 (^. The current density ratio of the electrode 1〇〇1&amp; and 1〇〇1!3 is 〇.5:1 To 10:1, the current density ratio on the electrodes l〇〇la and 1001c is from 0:5 to ❹50: the current density ratio on the electrodes 1001a and 1001d is 1:1 to 300:1. This step is at the electrode 1001a. , i〇〇lb, 1〇〇1 (: and 1〇〇1 (1 applies a relatively large current, thereby improving the efficiency of electrochemical deposition. This step is terminated by depositing the desired thick film. Step 7: Apply a small bias voltage to the semiconductor wafer. In one embodiment of the invention, the electrodes 1〇〇la, i〇〇ib, i〇01c Switching from current mode to voltage mode simultaneously with 1001d; in another embodiment of the invention 'electrode l〇〇la, l001b, 1001c* i001 (i switches from current mode to voltage mode at different times; step 8: The wafer is taken out from the electrolyte and rotated to remove residual electrolyte on the surface of the wafer; in the above steps 5 and 6, the positive and negative signs of the voltage of the electrode lld are determined by electrochemical deposition conditions. For example, when the conductivity of the electrolyte is low 'The surface of the semiconductor wafer is electrically conductive, and the electrodes l〇〇la, l〇〇lb, 1001c and looid are simultaneously applied with a positive voltage, as shown in FIG. 11a; when the conductivity of the electrolyte is high, the surface of the semiconductor wafer is thin, The electrodes l〇〇la, 1001b, and looic apply a positive voltage, and a negative voltage is applied to the electrode 1〇〇ld, 20 201012976 as shown in lib. In step 5, uniform on the 30 mm semiconductor wafer with a seed layer of 50 to 2000 Å. The current density ratio of the copper plating film and the positive and negative sign of each electrode voltage are set as shown in Table 9. The conductivity of the electrolyte used is 0. 0 2-0. 2S/cm and 0_ 2-0· 8S/ Cm : Table 9 Symbolic current density ratio of the symbol electrode 1001c of the symbol electrode 1001b of the electrode 1001a (1001a: 1001b) (1001a: 1001c) (1001a: 1001d) Conductivity 0. 02-0. 2 S/cm + + + + 0.5:1-2: 1 0.5:1-10 :1 1:1-300: 1 + + + - 0.5:1-2: 1 0.5:1-3: 1 10:1-100 :1 Conductivity 0. 2-0.8S /cm + + + 1:1-2:1 4:1-30:1 2:1-20:1 Reference Step When the thickness of the deposited copper film reaches 1500A, start step 6. The current density ratio and the positive and negative sign of each electrode voltage on the 300mm semiconductor wafer with a seed layer of .50 to 2000A are set as shown in Table 10. The conductivity of the electrolyte used is 0.02-0.2. S/cm and 〇.2-0.8S/cm : 21 201012976 Table ί The symbol current density ratio of the symbol electrode 1001d of the symbol electrode 1001b of the electrode 1001a of the electrode 1001a (1001a: 1001b) (1001a: 1001c) (1001a: 1001d) The conductivity is 0. 02-0. 2 S/cm + + + + 1:1-2:1 1:1-10: 1 1:1-300 :1 + + + a 0.5:1-2 :1 0.5 :1-1 0:1 10:1-30 0:1 Conductivity 0. 2-0. 8S /cm + + + 1:1-2:1 1:1-2:1 1:1-250 :1 Figures 12a and 12b illustrate the deposition curves of a 300 0A thick copper film deposited on a 35 0A seed layer, using electrolytes of low conductivity and high conductivity, respectively. The curve of Method 1 is obtained by using the process parameters of Table 9 and Table 10, and the curve of Method 2 is obtained by using the process parameters outside the range described in Table 9 and Table 10. The WFNU values are listed in Table 11. The method disclosed in Figures 1 2 a-1 2b and Table 11 provides a significant improvement in the deposition of the 3000A film layer with high conductivity and low conductivity electrolyte. The WFNU calculation of the deposition curve on the 300 mm semiconductor wafer excludes the edge 2. 3 mm area, which is much stricter than the exclusion edge used in the usual industry 3. 0 to 6. 5 mm area. 22 201012976 Low conductivity electrolyte High conductivity electrolyte Method 1 (disclosed = 〇 · 333⁄4 λ 66% Method 2 (conventional) _

WFNU

The use of high conductivity and low conductance (method 1) is more traditional than the method (method of the method, revealing the improvement of the method. Especially in the case of the use of the world "2), both make WFNU visible. You use low conductance WFNU is less than 2. 5%. In the case of a liquid, the obtained example 4 of the present invention is used in a simple electrode structure apparatus disclosed in U.S. Patent No. 6,391,166, and the method of the present invention is applied to a similar method. In an apparatus having an electrode structure of more than four electrodes, wherein the first electrode area of the structure is the total electrode area #5% to 3%, and the ratio of the sum of all the electrode areas to the area of the semiconductor wafer is larger than. 85. The current density ratio and the positive and negative sign of each electrode voltage are uniformly electric forged on a 300 mm semiconductor wafer of 50 to 2000 A in a layer of 50 to 2000 A. The specific setting is as shown in Table 12, and the electrolyte conductivity used is as shown in Table 12. 2·0-0. 2S/cm and 〇. 2-0. 8S/cm. In this case, the electrominening device has N electrodes and N can vary between 5 and 15. 23 201012976 Table 12 First to Nth N-1 Nth electric current density ratio electrode N-2 electrode electrode polarity symbol El : E2... (El : (El : symbol symbol En-2 En-1) En Conductivity + + + + 0.8:1-2: 0.5:1-10 1:1-30 0. 02-0. 2 1 :1 0:1 S/cra + + + - 0.5:1-2: 0.5 :1-3: 10:1-1 1 1 00:1 Conductivity + + + - 1:1-2:1 4:1-40:1 2:1-10 0. 2-0.8S 0:1 / After cm, the current density ratio and the positive and negative sign of each electrode voltage are uniformly plated on a 300 mm semiconductor wafer with a seed layer of 50 to 2000 A. The specific settings are as shown in Table 13, and the electrolyte is used. The rate is 0. 02-0. 2S/cm and 0. 2-0. 8S/cm : 24 201012976 Table 13 First second to N-1 Nth electric -----^ Current density tl* - - Electrode No. N-2 Electrode is El: -----(E1 : ------- (E1 : symbol electrode symbol No. E2... En-l) En) No. En-2 Conductivity + + + + 1:1-2:1 ----. 1:1-10 ------- 1:1-30 0.02-0. :1 0:1 2S/cm + + + - 0.5:1 -2 1 — A 0.5:1- 10:1-3 :1 10:1 00.1 Conductivity + + + A 1:1-2:1 1:1-2: —— 1:1-30 0. 2-0. 8 1 0:1 S/cm ❹ Table 13 shows the use of low conductivity electrolyte 1 and high conductivity electrolyte 2 respectively. In the case of the apparatus, a deposition curve of a beta 300 0 thick copper film on a 350A seed layer is used, wherein the apparatus of the embodiment has ten independently controllable electrodes. The WFNU value obtained by the method of the present invention is much lower than 2.5%, which is 〇26% in the electrolyte i and 〇.59% in the electrolyte 2. Based on the method disclosed in the present invention, the obtained WFNU can be improved as the number of electrodes N increases. When a device having a larger number of electrodes than J is used, the copper film is plated on a 350A seed layer wafer by these methods to obtain less than 2. 2.5% of WFNU. When N is increased to 4, the WFNU obtained by electrowinning on the same wafer and seed layer is reduced to 〇, 33%. 25 201012976 The method disclosed in the present invention is compared with the method disclosed in U.S. Patent No. 6,755,954. All conditions are met (4)·(1) Multi-electrode liquid-repellent electric material=〇.5 s/Cffi, (8) Xuanjing layer thickness=400A(4) Second, degree= 6_, and (5) exclude the edge of the wafer 2n s For direct comparison, replace the WFNU with a uniform thickness range. The green color shows the deposition curve calculated by the method disclosed in the present invention. Contrast values for the uniform range of thickness are listed in Table 14 e Table 14

Uniform range 240A reveals the uniform thickness range of the method

138. 4A The deposited copper film obtained by the method of the present invention has a WFNu of 0.72% and a uniform thickness range of 138.4 A, which is 2 times better than the method disclosed in U.S. Patent No. 6,555,954. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing the apparatus of the prior invention used in the method; FIG. 2 is a partial schematic view showing a single electrode plating apparatus; and FIGS. 3a-3d are diagrams showing deposition by a single electrode plating apparatus. Figure 4 is a partial schematic view of a two-electrode plating apparatus; Figures 5a and 5b show waveform diagrams used in a two-electrode device; 26 201012976 Figures 6a and 6b show the deposition curves obtained using a two-electrode device; A partial schematic diagram of a three-electrode plating apparatus is shown; Figures 8a and 8b show waveform diagrams used in a three-electrode apparatus; Figures 9a and 9b show deposition curves obtained using a three-electrode apparatus; FIG. 11a and lib show waveform diagrams used in a four-electrode device; FIGS. 12a and 12b show deposition curves obtained using a four-electrode device; ❹ FIG. 13 depicts deposition obtained using a ten-electrode device Fig. 14 shows the calculated deposition curve; [Major component symbol description] 401a, 701a, 1001a: first electrode 401b, 701b, 1001b: second electrode 701c, 1001c: electric three Electrode 1001d: fourth electrode 421 421, 721, 1021: wafer holding device 422, 722, 1022: semiconductor wafer 423a, 423b, 723a, 723b' 723c, 1023a, 1023b, 1023c, 1023d: fluid control device 27

Claims (1)

201012976 VII. Patent Application No. 1 A method for electrochemically depositing a uniform copper film device having two electrodes, comprising the following steps, wherein the first electrode area is 50%-9% of the total electrode area: electrolysis of sulfuric acid steel The liquid is injected into the apparatus at a flow rate of 1 to 2 〇LpM; the semiconductor wafer is transferred to the wafer holding device to make the device electrically contact with the wafer conducting layer; the 参 打开 opens the power source, and the semiconductor crystal g1 τ is kept weak. A bias voltage of up to 1 〇V is supplied; the semiconductor wafer is brought into contact with the electrolyte; the first electrode voltage is kept positive with respect to the wafer; and the first electroplating process is performed to the respective gates of the thunder The total current of the hinge is 2A to 10A. When the second electrode is positive with respect to the wafer, the current density ratio of the first electrode to the first electrode is au ^ field.1, when the second electrode voltage is relative to the day slice When it is negative, the ratio of the current density of the first electrode to the first electrode is 2:1-3〇:1; ^ The first step of the electroplating process is performed, and the supply of each of the λα minus α 10 to 40 总 total electricity Flow, when the second electrode voltage is relatively positive with respect to T曰曰, the current density ratio of the first electrode to the first electrode is 1 1-3 曰 κ &amp; 6 ± . .1, * the second electrode voltage is relative to the 曰 片When negative, the first electrode and 10:1-30:!; (4) current density ratio for the switching power supply to the semiconductor wafer to provide the maximum 崁 to the bias of ιον; the semiconductor wafer is taken out of the electrolyte. As in the method described in claim 1, the ratio of the total area of the electrodes to the wafer area is greater than 〇85. 3. If the method described in the third paragraph of the patent application is applied, the hole T is extended to the step-by-step plating time, when the voltage of the second electrode is negative with respect to the wafer, the conductivity is 0.02 to 2 S/cm electrolyte. The ratio of the first electrode to the _th current density is 15:1-30:1. The method of claim 1, wherein when the first step clock is performed, when the voltage of the second electrode is negative with respect to the wafer, the conductivity is 0.2 to 0.8 s/cmf: in the solution The ratio of the first electrode to the second current density is 2:1-15:1. 5. Please ask for the scope of patents! The method according to the item, wherein, when the second step of the electroplating process is performed, when the voltage of the second electrode is negative with respect to the wafer, in the electrolyte having an electric conductivity of 0.02 to 2.2 s/cm, the first electrode and the second electrode ❷ current The density ratio is 15: 1-30:1. 6. The method according to claim 1, wherein in the second step of the electric clock process, when the voltage of the second electrode is negative with respect to the wafer, the conductivity is 〇·2 to 〇.8^ electrolyte The ratio of the current density of the first electrode to the first electrode is 1 〇: 卜2〇.1. 7. The method of claim 1, wherein the semiconductor wafer layer has a thickness of 5 Å to 9 Å. 29 201012976 凊 The method of claim 1, wherein the semiconductor 趟 趟 趟 steel film is adjusted to within 2 2% to 2 5%. 9·4 Please refer to the method described in item i of the patent garden, in which the electrodes are placed at the same 1-direction height. Electrode The method described in claim 1 is placed at different longitudinal heights. U.- A method for an electrochemical deposition uniform copper film apparatus having three electrodes, comprising the following steps 'where [electrode area is 40%-6% of total electrode area: copper sulfate electrolyte is injected into the Equipment, traffic is! Up to 2〇LpM; send the semi-conductive wafer to the wafer holding device, so that the device has conductive contact with the wafer conducting layer; ❹ turn on the power supply to provide the semiconductor wafer with a bias voltage of up to 1〇V. Sending to the electrolyte to be in contact with it; maintaining the first electrode voltage positive with respect to the wafer; performing the first step of the plating process 'providing a total current of 2A to 1-8 to each electrode, when the third electrode voltage is relative to the wafer Timing, the ratio of the current density of the electrode to the second electrode of the flute is 4: the current density ratio of the first electrode to the third electrode is 1:1-300:1', when the third electrode voltage is negative relative to the wafer, the first The current density ratio of the electrode to the second electrode is 11-20^, and the current density ratio of the first electrode to the third electrode is 2:1-40:1; 201012976 performs the second step electroplating process, providing a sum of 1 〇A to each electrode The total current to 4〇A -, when the third electrode voltage is positive with respect to the wafer, the current density ratio of the first electrode to the second electrode is 1: 2:1, and the current density ratio of the first electrode to the third electrode is 1 : 1 -300: 1. When the third electrode voltage is negative relative to the wafer, The current density ratio of the first electrode to the second electrode is 1: 2:1, and the current density ratio of the first electrode to the third electrode is 20: 300: 1; the switching power supply provides a maximum of 1 〇v to the semiconductor wafer. Dust; The semiconductor wafer is taken out of the electrolyte. 12. The method of claim 2, wherein the ratio of the total area of all of the electrodes to the area of the wafer is greater than 〇85. The electrolyte is 0. 02至〇. 2S/cm electrolyte, when the first electrode is subjected to the first step of the electroplating process, when the voltage of the third electrode is negative with respect to the wafer, in the conductivity of 0. 02 to 2. 2S / cm electrolyte, The ratio of the first electrode to the _ pole current density is 1: Bu 2:1, and the first electrode and the first electrode are buds. The current density ratio of one electrode is 10:1-40:1. 14. The method of claim 11, wherein in the first step of the electroplating process, when the voltage of the third electrode is negative relative to the wafer, the conductivity is 〇. 2 to 8. 8s/cm in the electrolyte 'first The ratio of the electrode to the first in-phase current density is 5:1-20:1, and the ratio of the first electrode to the first electrode &amp;&amp; electro-deuterium current density is 2:1-10:1. Φ 31 201012976 15·Fangzhong, as described in the scope of patent application, in the second step of the plating process, when the voltage of the third electrode is negative relative to the wafer, the conductivity is 0_ 02 to 〇. 2S/CID In the electrolyte, the first life, the second lightning current density ratio in the electrode is 胄1: 2:1, and the ratio of the first electrode to the third power is 50·· 300:1. ; 11 up to 16. As described in the patent application, the method described in item 11, and... In the second step of the keying process, when the third electrode is negatively opposite to the wafer, the conductivity is 0.2S 〇.8S/cm. In the electrolyte, the _th electrode virtual second electrode current density ratio is, the first electrode and the third electrode current density ratio is 20: Bu 80:1. Wherein the semiconductor substrate has a seed layer thickness of 50 to 900 Å as described in claim U. 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。 。. 19. The method of claim U, wherein each electrode is placed at the same longitudinal height. 20 · If the pole of the patent application is placed at a different vertical height. The method of claim 11, wherein each of the electricity 32 201012976 21. A method for an electrochemical deposition uniform copper film apparatus having four or more electrodes, comprising the steps of: wherein the first electrode area is a total electrode 5% to 50% of the area, the copper sulfate electrolyte is injected into the apparatus at a flow rate of 2 〇LpM; the semiconductor wafer is transferred to the wafer holding device to make the device in conductive contact with the wafer conducting layer; Providing a semiconductor wafer with a bias voltage up to 丨〇v; _ bringing the semiconductor wafer into contact with the electrolyte; maintaining the first electrode voltage positive with respect to the wafer; performing a first step of electroplating to provide a sum to each electrode For the total current, when the first electrode voltage is positive with respect to the wafer, the current density ratio of the first electrode to the second electrode is 0.5:1-10:1, and the current density ratio of the first electrode to the last electrode is i : Bu 300: Bu current electrode and other electrode current density ratio of 0.5: 1-2: When the first electrode voltage is negative relative to the wafer, the first electrode and the second electrode current density ratio is 〇 5:12: 1, second The current density ratio of the φ electrode to the first electrode is Id-300:1, and the current density ratio of the first electrode to the other electrode is 0.5: Bu 30:1; the second step of the key bonding process is performed, and the sum of the electrodes is 1 〇A The total current to 4〇a, when the first electrode voltage is positive with respect to the wafer, the first electrode and the second electrode current density ratio is 〇.5:1-1〇:1, the first electrode and the last electrode current The density ratio is 1:1 -300:1, and the current density ratio of the first electrode to the other electrode is 0.8: 2: When the first electrode voltage is negative relative to the wafer, the current density ratio of the first electrode to the second electrode is 〇5:1_2:1, the first – the current density ratio of the electrode to the last electrode is 1: 1-300: 1, the first electrode and 33 201012976 other electrode current density ratio is 〇. 5 : 1 __丨〇. Summer, · 1 bias; switching power supply to the semiconductor wafer to the maximum to remove the electrolyte from the semiconductor wafer. 22. The method of claim 21, wherein the ratio of the total area of the electrodes to the area of the wafer is greater than 〇85. 23. The method of claim 21, when the first step of the electroplating process is carried out, when the voltage of the first electrode is 曰J曰曰月舄, the conductivity is 0. 02至〇. In the 2S/cm electrolyte, the current-density ratio of the first electrode to the second electrode is 0.5M-3: the current density ratio of the first electrode to the first electrode is 10:1-100:1, The current density ratio of one electrode to the other electrode is 0. 5: 1-2: 1» 24. The method according to claim 21, wherein the voltage of the first electrode is performed when the first step of the key process is performed. The relative density of the first electrode and the second electrode is 4:1-40:1, and the current density of the first electrode and the second electrode is negative in the electrolyte of 0.2 to 8 S/cm. The ratio is 2: 1-100: 1. The current density ratio of the first electrode to the other electrodes is 1: Bu 2:1. 25. The method of claim 21, wherein when the second step of the electroplating process is performed, when the voltage of the first electrode is negative relative to the wafer, in an electrolyte having a conductivity of 0.02 to 2.2 S/cm. The first electrode and the second electrode 34 and the first electrode electrode are in close contact with the other electrodes. ❹ 201012976 The electrode current density ratio is 〇. 5: 卜10: 丨 current density ratio is 1 (^ 1 - 200:1, The first ratio is 0.5:1-2:1. When the patent method is mentioned, the method is to make the second film in the second step of the electric ore process, when the last film is in the conductivity of 0.2 to 〇.8s/ c is negative with respect to the cymbal, the electrode current density ratio is m - H, the ratio of the first electrode to the second flow is the first electrode and the last electrode is 1:1 - 2: 1. The polarity of the electrode and other electrodes Ratio 27. The thickness of the seed layer of the 21st body wafer is 5 〇 to 9 〇〇 a. ^ 'Method, where the semi-guide 28. As claimed in the scope of the 21st I* a LJ L Φ method, which is rich The WFNU of the galvanized steel film on the body wafer is in the range of 0.2% to 2.5%. 29. If the scope of the application is in the 21st paragraph, the punch is placed in the same longitudinal direction. Height. A method 'wherein each electrically 3〇. Patent application range as item 21 placed at different longitudinal height of the pole. Method L' wherein each electrically 35