JP2006287270A - Semiconductor device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a semiconductor device and method of manufacturing the same, which can seal the ambient of a post metal with sufficient thickness with advantageous cost, and at the same time control the survival of voids in sealing resin. <P>SOLUTION: The semiconductor device comprises a circuit element, a plurality of electrode pads 20 conducting to the circuit element, a protection film 21 formed in such a way that a plurality of electrode pads 20 are made to be exposed on one surface side, where the circuit element is built, a plurality of re-circuit patterns 30, each of which conducts with each electrode pad 20, having a terminal 30a formed on the protection film 21, a post metal 4 formed on each terminal 30a, and resin layer 40 formed so as to surround the post metal 4. The height of the resin layer 40 is higher than that of the post metal 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method of manufacturing a semiconductor device using a wafer in which a plurality of regions to be individual semiconductor devices are provided, and each region is provided with a circuit element and a plurality of terminal pads that are electrically connected to the circuit elements. And to a semiconductor device.

  In recent years, a wafer level CSP (Chip Size Package) that performs a package process in a wafer state has attracted attention. The wafer level CSP is roughly classified into three types, that is, a sealing resin type, a rewiring type, and a wiring board type, depending on the structure. The sealing resin mold has a structure in which a plurality of columnar terminals (post metal) that are electrically connected to circuit elements are formed on the surface, and the periphery of these post metals is solidified with a sealing resin.

  The manufacturing process of a sealing resin type wafer level CSP having such a structure is usually performed by a process of forming circuit elements and wiring on a wafer, a process of forming passivation and a plurality of electrode pads, a rewiring process on the passivation, The method includes a step of forming a plurality of electrode portions, a step of forming a post metal on each electrode portion, a step of hardening the periphery of these post metals with a sealing resin, and a step of forming a solder terminal on each post metal. In the step of hardening the periphery of the post metal with a sealing resin, a transfer molding method using a mold or a spin coating method is generally employed.

  However, the transfer mold method is disadvantageous in terms of cost because it requires a mold, and when manufacturing several types of semiconductor devices, different molds are required according to the arrangement of the post metal, It is necessary to prepare multiple types of molds.

  On the other hand, the spin coating method uses a resin having a relatively low viscosity and coats the surface of the wafer by utilizing the centrifugal force generated by the rotation of the wafer, so that a resin layer having a relatively large thickness is formed. It is difficult. In addition, on the wafer surface on which a large number of post metals are formed, it is difficult for the post metal to obstruct the flow of the resin sufficiently, and this method is particularly unsuitable for highly viscous resins.

  Furthermore, the material resin contains not a little air and moisture, and when the periphery of the post metal is hardened using a thermosetting resin as a sealing resin, when the resin is heated and cured, There is a problem that moisture in the resin evaporates and expands, or air expands to form bubbles, which remain in the resin layer in the manufacturing process and eventually remain as voids.

  The present invention has been conceived under the circumstances described above, and can advantageously seal the periphery of the post metal with a sufficient film thickness in a sealing resin. It is an object of the present invention to provide a semiconductor device and a method for manufacturing the semiconductor device that can suppress the remaining of voids.

  In order to solve the above problems, the present invention takes the following technical means. That is, the semiconductor device provided by the first aspect of the present invention includes a circuit element, a plurality of electrode pads conducted to the circuit element, and the plurality of electrode pads on the one surface side where the circuit element is built. And a plurality of rewiring patterns each having a terminal portion formed on the protective film and electrically connected to the electrode pads, and formed on the terminal portions. The post metal and a resin layer formed so as to surround the post metal, and the height of the resin layer is higher than the height of the post metal.

  In a preferred embodiment, an external terminal is formed on each post metal.

  In a preferred embodiment, the plurality of terminal portions are arranged in a lattice pattern.

  According to a second aspect of the present invention, there is provided a method for manufacturing a semiconductor device, wherein a plurality of regions to be individual semiconductor devices are provided, and a circuit element and a plurality of electrode pads electrically connected to each of the regions are provided. A method of manufacturing a semiconductor device using a wafer provided with a step of forming a protective film on the wafer surface so as to expose the plurality of electrode pads, and each conducting with the electrode pads, And a step of forming a plurality of rewiring patterns having terminal portions formed on the protective film, a step of forming post metals on the terminal portions, and a resin layer so that the post metals are embedded. And forming the resin layer by a printing method. After the periphery of the barrel was filled with mucus Joka resinous, it is characterized by carried out by curing the resin.

  In a preferred embodiment, the method further includes a step of forming an external terminal on each of the post metals.

  In a preferred embodiment, in the step of forming the plurality of rewiring patterns, the plurality of terminal portions are arranged in a lattice shape.

  Here, as the “printing method”, for example, a mask on which a pattern is formed corresponding to the arrangement of the post metal is put on the wafer on which the post metal is formed, and in this state, the gap formed by each post metal is covered. There is a so-called screen printing method performed by imprinting a viscous resin.

  In the manufacturing method of the present invention, since the resin layer is formed by the printing method, there is no problem as in the case of forming the resin layer using the transfer molding method or the spin coating method described above. In other words, it is not only cost-effective because it does not require a mold, but it is also easy to form a relatively large resin layer, and even on the surface of a wafer on which many postmetals are formed, postmetal The resin layer can be formed with a uniform thickness over the entire wafer without much hindrance.

Also, in the resin layer formation process, when the resin layer is not sufficiently cured and the viscosity is not so large, the bubbles generated in the resin layer are usually accompanied by the growth of bubbles on the atmosphere side (outside of the resin layer). Try to move to). If the atmosphere is in a vacuum state, that is, a low pressure atmosphere (for example, a pressure range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mmHg), the movement of bubbles from the resin layer to the atmosphere side is promoted. In the process of forming the resin layer under vacuum, bubbles are gradually moved and discharged from the uncured resin layer into the atmosphere. Therefore, in the manufacturing method of this invention, it is suppressed that a bubble remains in a resin layer.

  Further, in the present invention, after performing the wafer stage in the same manner as in the prior art, the post metal and the resin layer are further formed in the wafer state without fractionating (dicing) the individual semiconductor chips. Individual semiconductor devices can be obtained by fractionating a wafer in this state (usually a wafer after external terminals are formed by solder or the like). As described above, in the present invention, all the processes until the semiconductor device is completed are performed in the wafer state, and the work is not performed in the semiconductor chip state. For this reason, in the manufacturing method of the present invention, the manufacturing process is simplified and the working efficiency is remarkably improved, which is advantageous in terms of cost. In addition, in the present invention, since the semiconductor device is obtained by dividing the wafer, the size of the provided semiconductor device is substantially the same as that of the semiconductor chip, and the miniaturization of the semiconductor device is achieved.

  Here, as the resin constituting the resin layer, in addition to a thermosetting resin such as a heat-melted epoxy resin or polyimide resin, a resin dissolved in an organic solvent and made viscous is used. For this reason, if the resin layer is formed in a heating atmosphere adjusted to an appropriate temperature, it is easy and convenient to adjust the viscosity and curing rate of the resin layer.

  Of course, each post metal itself may be used as a terminal for connection to a circuit board or the like, or an external terminal may be formed on the post metal by solder or the like, and this may be used as a terminal for connection. Examples of the method for forming the post metal include electroless plating, electrolytic plating, and printing. Here, the “printing method” is the same method as the printing method in the method of forming the resin layer described above. In this method, first, a resist layer (mask) in which appropriate through holes are formed is provided on a wafer, and a metal paste is applied to the resist layer. Then, the applied metal paste is spread with a squeegee or the like, and the paste is imprinted in the through hole. After the paste is cured, the resist layer is removed to form a post metal.

Further, the degree of vacuum at the time of forming the resin layer is set such that the pressure is 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mmHg in consideration of the apparatus cost for achieving the vacuum and the degree of suppression of remaining bubbles in the resin layer. A high vacuum that is in the range of about is preferable.

  Other features and advantages of the present invention will become more apparent from the detailed description given below with reference to the accompanying drawings.

  Hereinafter, preferred embodiments of the present invention will be specifically described with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of a semiconductor device obtained by the manufacturing method according to the present invention, and FIGS. 2 to 7 are diagrams for explaining the semiconductor device manufacturing method according to the present invention. However, in this embodiment, after first describing the semiconductor device obtained by the manufacturing method according to the present invention, the manufacturing method of this semiconductor device will be described.

  A semiconductor device 1 shown in FIG. 1 has a semiconductor chip 2 in which a circuit element (not shown) is integrally formed on one surface side. The semiconductor chip 2 includes a plurality of conductive elements connected to the circuit element. The electrode pad 20 is formed so as to be aligned with the peripheral edge thereof. A protective film 21 is further formed on one surface side of the semiconductor chip 2 so that each electrode pad 20 is exposed and the circuit element is covered.

  On the protective film 21, a plurality of rewiring patterns 30 that are electrically connected to the terminal pads 20 and have terminal portions 30a are formed. As described above, the electrode pads 20 are arranged on the peripheral edge of the semiconductor chip 2, but the terminal portions 30a of the rewiring pattern 30 are arranged in a grid, for example. That is, the arrangement of the electrode pads 20 of the semiconductor chip 2 is converted into a desired pattern on the protective film 21 by the rewiring pattern 30.

In addition, columnar terminals (post metal) 4 are formed on each terminal portion 30 a, and a resin layer 40 is formed so as to surround these post metals 4. The resin layer 40 is formed to have a thickness so that the surface thereof is flush with the front end surface of each post metal 4. On the front end surface of each post metal 4, a ball-shaped solder terminal 5 is provided. Is formed. The semiconductor device 1 having such a configuration can be surface-mounted on a circuit board or the like by remelting and solidifying the solder terminal 5.

  Next, a method for manufacturing the semiconductor device 1 having the above configuration will be specifically described with reference to FIGS.

  In the method for manufacturing a semiconductor device according to the present invention, a wafer Wf as shown in FIGS. 2 and 3 is used. The wafer Wf is entirely formed into a notch disk shape by silicon or the like, and a plurality of regions A to be individual semiconductor devices are provided. In each region A, a circuit element (not shown) is formed, and a plurality of electrode pads 20 that are conductive to the circuit element are provided so as to be arranged along the peripheral edge of each region A.

A protective film 21A is further formed on the wafer Wf so that each electrode pad 20 faces. The protective film 21A is formed, for example, by growing SiO ₂ or the like on the wafer Wf to have a predetermined film thickness by, for example, a CVD method, and then etching away portions corresponding to the electrode pads 20.

  In such a wafer Wf, as shown in FIG. 4, the rewiring pattern 30 is formed on the protective film 21A. The rewiring pattern 30 is obtained, for example, as an aluminum wiring having a terminal portion 30a, and is formed by photoetching or the like. As described above, each rewiring pattern 30 has terminal portions 30a arranged in a grid and is electrically connected to the corresponding electrode pad 20.

  Next, the post metal 4 is formed on the terminal portion 30 a of each rewiring pattern 30. As shown in FIG. 5A, the resist layer 6 that covers the rewiring pattern 30 is formed of, for example, a photosensitive material, and the portion corresponding to the terminal portion 30a is exposed and developed to form the through hole 60. Then, the terminal portions 30a are exposed. Next, as shown in FIG. 5B, each through hole 60 is filled with a conductor such as solder or gold to form a conductor portion 4 </ b> A to be the post metal 4. Filling the through hole 60 with the conductor is performed by plating or printing. The plating may be any method of electroless plating and electrolytic plating. In the printing method, for example, a relatively large amount of a paste-like conductor is applied onto the resist layer 6 and is spread into the through hole 60 using a squeegee while being spread. Finally, by removing the resist layer 6 by etching, a plurality of post metals 4 are simultaneously formed as shown in FIG.

Subsequently, as illustrated in FIG. 6, the resin layer 40 </ b> A is formed so as to seal the post metal 4. This resin layer 40A is formed under vacuum, for example, by a screen printing method or the like. That is, first, as shown in FIG. 6A, a mask M patterned corresponding to the arrangement of the post metal 4 is placed on the wafer Wf. Next, as shown in FIG. 6B, after a relatively large amount of resin 40a that has been made viscous by hot melting or solvent dissolution is applied onto the wafer Wf, the application resin 40a is flattened by the squeegee Sk. Then, the resin is imprinted around each post metal 4. Then, by removing the mask M and curing the coating resin 40a, as shown in FIG. 6C, each post metal 4 is embedded, and the front end surface of each post metal 4 and its surface are flush with each other. The resin layer 40A thus formed is formed. The degree of vacuum when forming the resin layer 40A is a high vacuum in a pressure range of 1 × 10 ⁻⁶ to 1 × 10 ⁻³ mmHg.

In this step, since the resin layer 40A is formed by the printing method, there is no problem as in the case of forming the resin layer 40A using the transfer molding method or the spin coating method. That is, since a mold is not required, it is advantageous in terms of cost, and it is easy to form a resin layer 40A having a relatively large film thickness, and a wafer Wf on which a large number of post metals 4 are formed is The resin layer 40A can be formed with a uniform thickness with respect to the entire wafer Wf without being obstructed by the post metal 4 so much.

  By the way, in a state where the resin layer 40A is not sufficiently cured and the viscosity is not so large, the bubbles generated in the resin layer 40A usually move to the atmosphere side (outside the resin layer 40A) with the growth. And If the atmosphere is a vacuum state, that is, a low-pressure atmosphere, the movement of bubbles from the resin layer 40A to the atmosphere side is promoted. Therefore, in the formation process of the resin layer 40A under vacuum, the resin layer in an uncured state Bubbles move from 40A into the atmosphere and are released. Therefore, in the manufacturing method of the present embodiment in which the formation of the resin layer 40A is performed under vacuum, it is possible to prevent bubbles from remaining in the resin layer 40A.

  Next, as shown in FIG. 7, solder terminals 5 are formed corresponding to the respective post metals 4. This step is formed, for example, by fixing a solder ball on the front end surface of the post metal 4 or by applying molten solder on the front end surface of the post metal 4.

  Finally, dicing is performed along the lines shown in phantom lines in FIG. 7, that is, the lines defining the region A in which the semiconductor device is to be formed, thereby obtaining the individual semiconductor devices 1 as shown in FIG. .

  As described above, in the manufacturing method of the present embodiment, after performing the wafer stage in the same manner as in the past, this is divided (diced) into individual semiconductor chips, and further in the wafer state in the post-metal state. 4. By forming the resin layer 40A and the solder terminals 5, and fractionating the wafer Wf in this state, individual semiconductor devices 1 can be obtained. That is, since all processes until the semiconductor device 1 is completed are performed in a wafer state and work is not performed in a semiconductor chip state, in the manufacturing method of this embodiment, the manufacturing process is simplified and the work efficiency is improved. Significant improvement and cost advantage. Moreover, in the manufacturing method of the present embodiment, since the wafer Wf is divided into the semiconductor device 1, the size of the semiconductor device 1 is substantially the same as that of the semiconductor chip 2, and the semiconductor device 1 is downsized. Has been achieved.

  The technical idea of the present invention is applicable to all semiconductor devices in which a plurality of post metals are formed so as to be electrically connected to electrode pads, and a resin layer is formed so as to surround these post metals. That is, in the present embodiment, the method of manufacturing the semiconductor device in which the rewiring pattern is formed on the protective film and the post metal is formed on the rewiring pattern has been described. However, the so-called interlayer insulation is formed on the protective film. The present invention is also applicable to a method of manufacturing a semiconductor device in which a film is formed, a rewiring pattern is formed on the interlayer insulating film, and a post metal is formed on the rewiring pattern. Of course, the post metal is formed directly on the electrode pad, or the post metal is formed so as to be indirectly connected to the electrode pad via the bump terminal provided on the electrode pad. The present invention is also applicable as a method for manufacturing a semiconductor device.

It is sectional drawing showing an example of the semiconductor device manufactured by the manufacturing method which concerns on this invention. It is the wafer in which the circuit element and the electrode pad were built, and its principal part enlarged view. It is sectional drawing which follows the III-III line of FIG. It is wafer sectional drawing for demonstrating the manufacturing method which concerns on this invention. It is wafer sectional drawing for demonstrating the manufacturing method which concerns on this invention. It is wafer sectional drawing for demonstrating the manufacturing method which concerns on this invention. It is wafer sectional drawing for demonstrating the manufacturing method which concerns on this invention.

Explanation of symbols

Wf wafer A region (semiconductor device should be formed)
1 Semiconductor Device 4 Post Metal 20 Electrode Pad 30 Rewiring Pattern 40A Resin Layer

Claims (6)

Circuit elements;
A plurality of electrode pads conducting to the circuit element;
On one side where the circuit element is built, a protective film formed so as to expose the plurality of electrode pads;
A plurality of redistribution patterns each having a terminal portion that is electrically connected to each of the electrode pads and formed on the protective film;
Post metal formed on each of the terminal parts,
A resin layer formed so as to surround the post metal,
The semiconductor device according to claim 1, wherein a height of the resin layer is higher than a height of the post metal.   The semiconductor device according to claim 1, wherein an external terminal is formed on each post metal.   The semiconductor device according to claim 1, wherein the plurality of terminal portions are arranged in a lattice pattern. A method of manufacturing a semiconductor device using a wafer in which a plurality of regions to be individual semiconductor devices are provided and each of the regions is provided with a circuit element and a plurality of electrode pads that are electrically connected to the circuit elements.
Forming a protective film on the wafer surface to expose the plurality of electrode pads;
Forming a plurality of redistribution patterns each having a terminal portion formed on the protective film and electrically connected to the electrode pads;
Forming a post metal on each of the terminal parts;
Forming a resin layer so that each post metal is embedded;
Dividing the wafer into the individual semiconductor devices by dividing the wafer into the regions,
The step of forming the resin layer is performed by filling the periphery of each post metal with a viscous resin by a printing method and then curing the resin.   The method of manufacturing a semiconductor device according to claim 4, further comprising a step of forming an external terminal on each post metal.   6. The method of manufacturing a semiconductor device according to claim 4, wherein, in the step of forming the plurality of rewiring patterns, the plurality of terminal portions are arranged in a lattice shape.

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