TW594895B - Method for forming redistribution layer on semiconductor device - Google Patents

Abstract

A method for forming a redistribution layer on a semiconductor device is disclosed. First, a titanium layer is formed on a surface provided with a plurality of contact pads of the semiconductor device, an aluminum layer is formed on the titanium layer and a copper layer is formed on the aluminum layer. Then, the copper layer, the aluminum layer and titanium layer are patterned to form a patterned copper layer, a patterned aluminum layer and a patterned titanium layer. Then, the patterned copper layer is removed but the patterned aluminum layer and the patterned titanium layer are left intact to form a plurality of conductive traces, wherein each conductive trace has one end connecting with one contact pad of the semiconductor device. A dielectric layer is formed on the semiconductor device and conductive traces. A plurality of blind vias are formed on the dielectric layer and correspond to the other end of the conductive traces. A plurality of bumps are formed on the conductive traces through the blind vias and electrically connected with the conductive traces.

Description

594895 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a method for forming a redistribution layer on a semiconductor device. [Prior art] Traditionally, integrated circuits have been formed on the surface of a silicon substrate and have conductive pads formed on the periphery of the silicon substrate. Generally speaking, wire bOnds are connected to the conductive pads so that the conductive pads are electrically connected to the package substrate. The electronic circuits included in the integrated circuit are becoming more and more complicated. , The number of input connections (input connection) and output connections (out connection) of the integrated circuit also increases. Due to the increase in the output connection and the input connection, the input and output I electrical pads of the integrated circuit () npU 'and output conductive ρ & (〇 are distributed closer to each other: Γ .: Use Λ as the integrated circuit The distance between the conductive pads of the input or output (PUch) should be reduced as the circuit becomes more complicated. 绫 ί L! Ί The distance between the conductive pads of the input or output is reduced to make the structure = connect, dlngwire). The width should be more narrow and: The connection: the distance is not enough, and the increased output is based on the circuit's circumference Iflm + the connection should be set around the package bag, so a longer connection line is required. Increasing the mechanical limit of the vehicle. First, the long-distance cable's electrical properties and the safety of the machine include considerable inductance. 594895 5'Inventance (2) (inductance) 〇 Zenglikou's electronic signal transmission Speed. This movement may be at least temporarily their mechanical stability. The mechanical stability of the soldering bumps instead of wire bonding on the electrical connection is generally greater than the conductive pads required for wire bonding. even It is usually comparable to this soldering, and it is difficult to form solder bumps that provide electrical connection to the inside of the conductive pad provided on the surface of the Shi Xi substrate than the physical distance. Therefore, the number of blocks can be increased. However, The electrical pads are designed around the silicon substrate and the original manufacturing process. The end redistribution layer (I / O redistribut is connected to the surface of the silicon substrate. However, the material surface forming the port end redistribution layer is formed. A plurality of conductive lines are formed separately from the conductive metal. Since the conductive pads are mostly formed of aluminum. When forming aluminum circuits, the surface of the hair substrate is easily formed when exposed to air. The inductance of the etching line will be reduced by passing through the connection line, and the increase of the length of the connection line will be reduced due to a short circuit between the jitters. The inductance of the connection line can be reduced by forming on the conductive pad connection. In addition, the good connection is good 'However, the solder bumps are spaced or spaced. That is, the solder bumps are formed more densely. Because the solder pads are originally formed on the conductive pads. The conductive pads < Allow the conductive pads to protrude from the solder that is electrically connected to the integrated circuit. Many integrated circuit designs have this conductive edge. In order not to change the integrated circuit, a port layer could be formed on the surface of the silicon substrate). An important step is to electrically connect the conductive pads with solder bumps. An important step is to connect the silicon-based electrical pads and the solder bumps as inscribed pads. Therefore, the clothing of the metal circuit needs to be The metal is patterned by means of etching. However, since aluminum has an oxide layer and the aluminum oxide layer is not difficult. Therefore, when etching aluminum metal,

Page 9 594895 V. Description of the invention (3) There are often problems with slow etching and uneven etching. SUMMARY OF THE INVENTION The main object of the present invention is to provide a method for forming an aluminum circuit on a semi-conductor device to overcome or improve the aforementioned problems. A method for forming a redistribution layer on a semiconductor device according to the present invention. First, a titanium layer is formed on a surface of the semiconductor device having a plurality of contacts, a inscription layer is formed on the titanium layer, and a copper layer is formed on the inscription layer, so that the inscription layer directly contacts the titanium layer and The copper layer directly contacts the aluminum patterned patterned resist layer to benefit the patterned patterned layer. And an electric layer that has been wired is formed into a plurality of layers. Then, after the copper layer, the copper layer, the aluminum layer and the copper layer have been mapped, the patterned copper layer, the copper layer of the Ming layer and the copper layer are removed, and then the patterned titanium layer is removed to secure the end connection. The blind holes of the semiconductor device pass through the blind patterned copper acid solution to the bumps. The dilute 1 deionized water (the aluminum layer and the patterned copper layer of the titanium layer are covered by the photoresist layer), and the patterned aluminum layer has been patterned and the copper is completely formed to form the semiconductor wafer and the lead should be on the lead. Porous electrical connection layer and removing the acid-soluble ionized wa, aluminum layer and titanium layer to form a patterned and a patterned titanium layer. At the moment, a patterned light, aluminum layer and titanium layer will be formed The steps can be performed by masking. In addition, the photoresist layer can be removed, and the layer can be patterned using the mask but the patterned aluminum layer can be formed into a plurality of leads. Pad. Then, a dielectric surface is formed. The other end of the dielectric layer is shaped. Finally, it is formed on the lead. The remaining etchant of the copper layer may be a dilute liquid mainly composed of nitric ter, Cool acid

594895 V. Description of the invention (4) ac id) and hydrogen peroxide. In addition, the patterned copper layer can also be removed by electrochemical etching, but the patterned aluminum layer and titanium layer can be kept intact. The etchant suitable for patterning the aluminum layer may be a diluted acid-filled solution. The dilute scale acid solution is mainly composed of phosphoric acid, deionized water, and acetic acid. The etching solution for engraving the titanium layer is mainly composed of ammonium hydroxide, hydrogen peroxide, and deionized water. ^ The titanium layer is also etched with an etching solution mainly composed of hydrogen fluoride, hydrogen peroxide, and deionized water. The present invention uses a copper layer to protect the aluminum in the redistribution layer on the semiconductor device: the surface is not exposed to the air, so that it can be engraved smoothly and the aluminum layer, and finally the pattern is set to be patterned. I line. Because the tank is under the copper layer: under the guarantee, it will not hinder the corrosion. You can save money by engraving the inscription layer and get uniform inscription lines. 4 sets of moon daggers are effective = Ming Yi Er is used to form — The method. One hundred years ago, a protective layer was formed on the aluminum layer, such as a copper layer, on the aluminum layer, and a metal layer (such as a copper layer) was formed on the aluminum layer. Then, β is patterned; the protective metal layer is made straight-the patterned protective metal layer is formed of the metal layer and the indentation layer to form the patterned protective metal layer but the inscription layer is formed. Finally, when the protective metal layer is a copper layer, the case layer remains intact. The etchant for removing the copper layer may be a patterned copper layer and a diluted stone acid solution. The diluted nitrate page 11 594895

The acid solution is mainly composed of nitric acid, deionized water, acid donating, and hydrogenated gas. In addition, the patterned copper layer can also be removed in an electrochemical manner, but the patterned aluminum layer and titanium layer can be kept intact. / The #etching agent suitable for patterning the layer may be a diluted phosphoric acid solution. The diluted phosphoric acid solution is mainly composed of phosphoric acid, deionized water, and acetic acid. The method provided by the present invention may further include forming a titanium layer on the semiconductor device before the aluminum layer forming step. When patterning the protective metal layer, the shao layer and the Chin layer, a patterned photoresist layer will be formed on the protective metal layer. The patterned protective metal layer, Ming layer and titanium layer can be used together. The patterned photoresist layer is performed as a mask. In addition, the photoresist layer can also be removed after the step of patterning the copper layer and the aluminum layer, and the patterned protective metal layer and the patterned aluminum layer can be used as a mask to etch the titanium. Floor. The remaining etching solution for engraving the titanium layer is mainly composed of ammonium hydroxide, hydrogen peroxide, and deionized water. In addition, it can also be an etching solution mainly composed of hydrogen fluoride (hydrogen fluoride), hydrogen peroxide, and deionized water. [Embodiment] Figures 1 a-1 d illustrate the main steps of forming a conductive circuit in a semiconductor device according to an embodiment of the present invention. Referring to FIG. 1a, an aluminum layer 108 is first formed on the semiconductor device. The semiconductor device includes a 9 substrate 102, a plurality of metal pads 104 (usually aluminum pads or copper pads), and a dielectric layer (such as a protective layer 106). The substrate 102 may include a layer and a half

Page 12 594895 V. Description of the invention (6) Conductor materials (such as silicon, gallium arsenide, silicon carbide, diamond, or other well-known substrate materials). The protective layer 106 can be a polyimide layer, a silicon dioxide layer, a silicon nitride layer, or another protective layer material known in the industry. As shown in the figure, the protective layer 106 preferably covers the entire upper surface of the substrate 50 and has a plurality of openings corresponding to the positions of the pads 104, so that the pads 104 are It is exposed on the protective layer 106 and directly contacts the aluminum layer 108. Then, a protective metal layer such as a copper layer 110 is formed on the IS layer 108, so that the | g layer 108 is completely covered without being exposed to the air, thereby preventing the aluminum layer 108 from generating surface oxidation. The phenomenon. In the next step, a photoresist layer 112 is coated and the photoresist layer 2 is patterned. Referring to FIG. 1 b ′, using the pattern structure of the photoresist layer 112 as a mask, the copper layer 110 and the aluminum layer 08 are formed to form a patterned copper layer 11 0 a and Patterned aluminum layer 108a. At this time, the patterned surface layer 108a has a pattern of a predetermined conductive line. In this step of this embodiment, the etchant used to pattern the copper layer and the aluminum layer may be a diluted nitric acid solution and a diluted phosphoric acid solution, respectively. The diluted acid solution is mainly composed of nitric acid, deionized water, acetic acid, and hydrogen peroxide. In this embodiment, the ratio of each main component of the diluted nitric acid solution is 84% of deionized water, 5% of acetic acid, 5% of hydrogen peroxide, and 10% of nitric acid, and the etchant is heated to 50%. 〇Etching. The patterned food engraver can be a dilute phosphoric acid solution. The diluted phosphoric acid solution is mainly composed of phosphoric acid, deionized water, and acetic acid. In this embodiment, the

594895 V. Description of the invention (7) The ratio of each main component of the diluted phosphoric acid solution is 6% of deionized water, 11% of acetic acid, and 83% of phosphoric acid, and the etchant is heated to 60 t for the last name engraving. Referring to FIG. 1c, the photoresist layer 2 on the copper layer 110a is removed. Referring to FIG. 1d, the patterned copper layer 110a is then removed by an etchant patterning the copper layer, but the patterned aluminum layer 1083 is kept intact, thereby obtaining a uniform aluminum circuit at the remaining time. In this embodiment, this step can also be performed in an electrochemical manner. The electrolytic solution used in the electrochemical coining process is mainly composed of potassium sulfate (K1SO.) And glycerol (glycer0). In this embodiment, the electrolyte solution contains 0.4 M potassium sulfate and 1.5 M glycan oil. Referring to FIGS. 2a-2e, the present invention further provides a process for forming a redistribution layer on a semiconductor wafer 2000 by using the method described in FIGS. 1a to 1d. Referring to FIG. 2a, first, a titanium layer 206, an aluminum layer 208, and a copper layer 210 are sequentially sputter-deposited on the surface of the wafer 200 having the bonding pad 202. The thickness of the titanium layer 206 is about lkA, and the thickness of the aluminum layer 208 is about 4 women. Referring to FIG. 2b ', the titanium layer 206, the inscription layer 208, and the copper layer 2 10 are selectively etched to form a lead 2 1 2. One end portion of the lead 2 1 2 is connected to the aluminum pad 20 2, and the other end portion thereof extends on the protective layer 204. In this example, "the copper layer 2 10 is etched by using the aforementioned diluted nitric acid solution I and the aluminum layer 208 is etched by using the aforementioned diluted phosphoric acid solution, and then the original photoresist layer is used as a mask or The titanium layer 206 is etched with the patterned copper layer 21a and the aluminum layer 208a as a mask. An etching solution for etching the titanium layer 206, the main

Page 14 594895 V. Description of the invention (8) It should be composed of ammoni um hydroxi de, hydrogen peroxide and deionized water. In addition, an etching solution mainly composed of hydrogen f luori de, hydrogen peroxide, and deionized water may be used to etch the chin layer 206. Referring to FIG. 2c, the patterned copper layer 2 10a is removed first, so that the patterned copper layer 208a and the titanium layer 206a are kept intact. Then, a dielectric layer 214 (preferably made of polyimide) is covered on the leads 212 and the protective layer 204, and a light-defining blind hole is formed on the dielectric layer 214 ( Mouth 11〇1: 〇- (16 to 116 (11) 1111 (1- ¥ 13) 2143 corresponds to the end of the lead 212 away from the aluminum pad 202.... Refer to FIG. 2d 'A bump under the metal layer 216 cover In the blind hole 214a. The under bump metal layer 216 preferably includes a nickel / starved layer 2i6a as a barrier layer covering the blind hole 214a and the aluminum layer 208a of the lead 212; and The copper layer 216b serves as a wetting layer on the nickel / vanadium layer 2 1 6a. Referring to FIG. 2e, a solder bump 218 is provided on the copper layer 216b. The solder bump 2 1 8 It can also be replaced by a gold bump. The invention uses a copper layer to protect the aluminum layer on the semiconductor device, so that the surface of the aluminum layer is not exposed to the air, thereby smoothly and simultaneously engraving the copper layer and the aluminum layer, Finally, the patterned copper layer is removed to obtain a pre-set patterned inscription circuit. Since the ILu layer is under the protection of the copper layer, it does not As for the oxide layer that hinders the etching, the aluminum layer can be efficiently etched and uniformly patterned. In addition, the copper layer can also be replaced by gold or other precious metals to protect the aluminum layer, and the same can be achieved. Of ^ 594895

As described above, the method for forming a conductive circuit provided by the present invention can be used to form a port-side redistribution layer to electrically connect conductive pads scattered around a semiconductor device to external and external points of an array distributed inside the semiconductor device ( (Such as solder bumps). In addition, referring to Figures 3a-3c, the method for forming a conductive circuit provided by the present invention can also be used to distribute a plurality of conductive pads 3 02 (as shown in Figure 3a) distributed in a central area of a semiconductor array 3/0. (Shown) The conductive line 304 formed by the method described in the la-Id diagram is electrically connected to the external connection point 306 (as shown in FIG. 3b) distributed in the area around the semiconductor device 300, and then The semiconductor device 300 is electrically connected to a US board 308 in a wired manner. In the present embodiment, the wiring configuration "that is not conducive to wire bonding" (that is, the pad 302 concentrated in the semiconductor device's central region shown in Figure 3a) is redistributed to allow wire bonding. (That is, the contacts 3 0 6 that distribute the half area shown in Figure 3b). The example reveals, but it is not intended to be limited to the spirit and modification of the present invention. Therefore, the protection scope of the present invention shall prevail. Although the present invention has been formulated with the foregoing preferred implementation, anyone skilled in the art can make various changes and repairs within the scope of the scope of patents attached to the application. 594895 Description] In order to make the above and other objects, features, and advantages of the present invention obvious, the following describes the preferred embodiments of the present invention in cooperation with the following descriptions. Detailed description is as follows. No. 1 a-Id diagram : A cross-sectional view illustrating the main steps of forming a circuit in a semiconductor device according to an embodiment of the present invention; and e diagram: a cross-sectional view illustrating the main steps of forming a ^ 3a circuit in a semiconductor device according to another implementation of the present invention; And the conductive diagram ^ The above view shows the main steps of forming a semiconductor device into a semiconductor device according to another embodiment of the present invention. Description of the drawing number: 100 semiconductor substrate 10 4 pad 10 8 aluminum layer 110 Copper layer 112 Photoresist layer 2 0 0 Semiconductor wafer 204 Protective layer 2 6 Titanium layer 2 0 8 Aluminum layer 210 Copper layer 212 Lead 214 Dielectric layer 102 Substrate 106 Protective layer 108a Patterned aluminum layer 110a Patterned steel Layer 2 02 Aluminum pad 206a patterned titanium layer 2 0 8 β patterned | Lu layer 210a Patterned copper layer 214a Blind hole 594895 Brief description of the diagram 216 216a 218 300 304 308 Metal layer under the bump nickel / vanadium Layer solder bump semiconductor device conductive circuit substrate 2 1 6b copper layer 2 30 2 conductive pad 30 6 external point

Page 18

Claims (1)

594895 VI. Application Patent Scope 1. A method for forming a redistribution layer on a semiconductor device, which includes the following steps: forming a titanium layer on a surface of the semiconductor device, wherein the semiconductor device has A plurality of pads are disposed on the surface; forming an aluminum layer on the titanium layer so that the aluminum layer directly contacts the titanium layer; forming a copper layer on the aluminum layer so that the copper layer directly contacts the aluminum layer; patterning the Copper layer, layer, and titanium layer to form a patterned copper layer, a patterned aluminum layer, and a patterned titanium layer; remove the patterned copper layer but make the patterned | Lu layer and The patterned titanium layer remains intact to form a plurality of leads, wherein one end of each lead is connected to one of the pads of the semiconductor wafer; forming a dielectric layer on the semiconductor device and the surface of the leads; and A plurality of blind holes are formed on the dielectric layer respectively corresponding to the other ends of the leads; and a plurality of bumps are formed on the leads through the blind holes and are electrically connected to the leads. . The method for applying to a semiconductor device described in item 1 of the patent application scope "wherein the patterning of the copper layer is performed in step two, and the second remaining two two two to two steps include the use of a first food engraving agent. Carved the copper layer, ac id), X ^ is a dilute nitric acid solution containing nitric acid (ni tr ic black water, acetic acid, and hydrogen peroxide. It is used in a semiconductor as described in the first item of the patent scope On device Page 19 594895 VI. Method for forming a heavy cloth layer in the scope of patent application, wherein the patterning step of the inscription layer includes etching the inscription layer with a second etchant, the second etchant is a diluted phosphoric acid solution Containing phosphoric acid, deionized water, acetic acid 〇4, as described in the scope of the first patent application for a semiconductor device > method of forming a redistribution layer The step of removing the patterned copper layer is achieved by an electrochemical etching process. 5. The method for forming a heavy cloth layer on a semiconductor dream f as described in item 1 of the scope of the patent application, the bean paste and the engraving agent are engraved, and the third decoration step is-the third silver hydroxide ) ^ i5 ir ^ ^ 『ammon i um hydroxide has been treated with hydrogen peroxide and deionized water. 6. According to the scope of the patent application, the method of forming a heavy distribution layer = as described in item 1 is used for etching on a semiconductor device, in which the etching step of the titanium layer is a third etching. f luoride), peroxy, and each etchant contains hydrogen fluoride (hydrogen emulsified oxygen and deionized water. 7. As described in the patent application method ^ j method of forming a heavy cloth layer) used on a semiconductor device ^ Contains forming a patterned #, wherein the step of cladding and the titanium layer before the step of patterning the copper layer is layered on the copper layer, and the patterned copper layer and inscription are used. The step is to use the patterned Photoresist layer for mask Page 594 895 8. If you apply for a patent, please give us a picture! κ Forming-re-layout layer: The first method used to form a patterned semiconductor layer on a semiconductor device is described in the first step of cladding and aluminum layer before the step of patterning the copper layer = ° On the Hai steel layer, and on the patterned copper system, the patterned copper layer is used to perform the step of masking the titanium layer. Said μ has a patterned layer as a mask. 9. The method of forming a redistribution layer as described in the scope of the patent application, to form the dielectric layer. Item 1 is used on a semiconductor device in the form of polyimide (P 〇 1 y i m i d e) 10. A method for forming a semiconductor device comprising the following steps: forming a conductive layer on a semiconductor device to form an aluminum layer on the semiconductor device so that the protective metal layer is directly connected Forming a metal retaining layer on the aluminum to contact the aluminum layer; 9 to form a patterned protective gold but to pattern the protective aluminum layer and the protective metal layer and the aluminum layer and a patterned aluminum layer ; Remove the patterned protective metal with ^; complete. q 11 594895 Six 'application reversal — The step of patterning the copper layer and the step of removing the patterned copper layer include etching the copper layer with two or one etchant, the first etchant is a diluted 1 nitric acid solution containing Nitric acid, deionized water, acetic acid, and hydrogen peroxide. t 1 2. The method for forming a conductive line = a semiconductor device as described in item 10 of the scope of patent application, wherein the step of patterning the aluminum layer includes the step of etching the aluminum layer with a second etching agent, The second etchant is a diluted dish acid solution containing phosphoric acid, deionized water, and acetic acid. 13. The method for forming a conductive circuit in a semiconductor device as described in item 10 of the scope of patent application, wherein the step of removing the patterned protective metal layer is achieved by an electrochemical I-etching process. 14. The method for forming a conductive circuit on a half-body device as described in item 10 of the scope of patent application, further comprising forming a titanium layer on the semiconductor device before the aluminum layer forming step, and using the patterned The protective metal layer and the patterned aluminum layer serve as a mask to etch the titanium layer. _15. The method for forming a conductive circuit on a semiconductor device as described in item 10 of the scope of patent application, further comprising forming a titanium layer on the conductive device before the aluminum layer forming step, and in which The step of patterning the protective metal layer includes forming a patterned photoresist layer on the protective metal. 594895 6. Scope of patent application On the layer, the step of patterning the protective metal layer, the aluminum layer, and the layer is performed by using the patterned photoresist layer as a mask. 16. The method for forming a conductive circuit on a semiconductor device as described in item 14 or 15 of the scope of the patent application, wherein the remaining step of the thin layer is performed with a third I insect engraving agent | insect engraving, The third etching agent includes ammonium hydroxide, hydrogen peroxide, and deionized water. 17. The method for forming a conductive circuit in a semiconductor device as described in item 14 or 15 of the scope of the patent application, wherein the remaining step of the titanium layer is etched with a third etchant, and the third etch The agent contains hydrogen fluoride, hydrogen peroxide, and deionized water.