KR20100064042A - Apparatus of electroplating and manufacturing method of through via filling for wlp - Google Patents

Abstract

PURPOSE: An electrolytic plating device and a method for manufacturing a wafer penetration electrode are provided to improve electrical reliability by increasing adhesion inside a hole with a metal seed layer. CONSTITUTION: An electrolytic plating device includes a cathode auxiliary device(10) and an anode and fills a penetration hole of a wafer with conductive materials. A cathode auxiliary device includes an elastic pad, a pressure unit(16), and a metal film(13). The wafer is arranged on one side of the elastic pad. The pressure unit pressurizes the elastic pad in the direction of the wafer. The metal film is interposed between the elastic pad and the wafer, is replaceable, and is electrically connected to the anode.

Description

Apparatus of electroplating and manufacturing method of Through Via Filling For WLP}

The present invention relates to an electroplating apparatus and a wafer through electrode manufacturing method.

In order to form a via of the wafer, a through hole is formed by using a sand blasting, laser, and deep reactive ion etching (DRIE) method, and a through electrode is formed by filling the through hole with a conductive material.

In recent years, with the trend toward miniaturization and thinning of electronic components, research on 3D wafer level packaging (WLP) has been actively conducted, and the through hole inner diameter for wafer level packaging becomes smaller, and more conductive materials filling the through holes are used. There is a need for a technique of uniformly filling.

Existing methods for filling through holes are plugging or photosensitive resin, solder, metal thin film, etc. (plugging or PR bonding or metal bonding) to block one side of the hole and fill the inside of the through hole with electroplating.

The method of plugging one surface of the through hole by electroplating may include forming a metal seed layer for electroplating by sputtering and metal evaporation on one surface of the through hole, and plugging one surface by electroplating. And filling the inside of the through hole with electroplating. This method ensures adhesion inside the through hole, but causes excessive plating on the wafer surface to plug one side of the through hole. This causes wafer warping and cracking, and increases the cost and time of chemical mechanical polishing (CMP) for removing unnecessary plating layers. In addition, the plating layer formed on the inner side of the hole during plugging increases the occurrence of internal defects such as voids and seams during electroplating for complete metal filling in the hole.

In the method of bonding one surface of a through hole using solder, a photosensitive resin, and a dry film, many detailed processes are added before and after the electroplating process to fill the hole. In order to form and remove the metal seed layer used as the conductive layer, an additional process such as a photolithography process and a thermal curing is required, which increases cost and time, and a wafer damage problem due to thermal shock because a heating process is added after filling through holes. You should also consider. In addition, when solder is introduced into the through-holes generated during the use of solder, and the photosensitive resin is used, the inside of the hole is contaminated with the residue of the photolithography process inside the hole, making it difficult to manufacture a through-hole of uniform size.

Other methods have been proposed in which through-hole inlets are covered with a conductive tape, a conductive film, etc., and a through-electrode is manufactured using the conductive layer as a conductive layer. It is difficult to manufacture through, and it is difficult to secure electrical and structural reliability of the package process due to weak adhesion inside the through hole.

The present invention provides an electrolytic plating apparatus and a wafer that can perform a highly reliable plating by using a cathode auxiliary device for plating a wafer, and electroplating a through-hole having a high aspect ratio using the same. It is to provide a through electrode manufacturing method.

According to an aspect of the present invention, an electroplating apparatus including a negative electrode auxiliary device and a positive electrode, and filling the through-holes of the wafer with a conductive material, the negative electrode auxiliary device includes an elastic pad on which a wafer is seated; A pressing device for pressing the elastic pad toward the wafer at the other surface of the elastic pad; And a replaceable and electrically connected metal foil interposed between the elastic pad and the wafer.

The elastic pad may include at least one of silicon, foamed silicone, and rubber, and may further include a wafer holding device for holding the wafer in contact with an end of the wafer, and the wafer holding device may have elastic sealing at a portion in contact with the wafer. Can be further formed.

Providing a wafer having through holes formed therein; Physically pressing and fixing the metal foil on one surface of the wafer; And electrically connecting the metal foil with the conductive material to be plated, thereby filling the through holes with the conductive material.

The physical pressing method may be performed by pressing the pressing pad toward the wafer via a metal foil between the pressing pad including the elastic member and the wafer.

Before fixing the metal foil, the method may further include forming a metal seed layer on an inner wall of the through hole on one side of the wafer.

The metal seed layer may be further formed on one surface of the wafer. The method may further include removing the metal foil after the filling of the through hole.

According to a preferred embodiment of the present invention, the electroplating process for plugging can be omitted, the chemical mechanical polishing process of the plugging surface can be minimized, and defects in the holes such as voids or seams are generated. I never do that. In addition, since the metal foil is in close contact with the physical pressing method, a process for a separate detachment process may be omitted, and damage to the wafer due to thermal shock applied during detachment may be minimized. The presence of the metal seed layer increases the adhesion within the hole, resulting in an electrically structurally reliable package.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, preferred embodiments of an electroplating apparatus and a method of manufacturing a through-electrode electrode according to the present invention will be described in detail with reference to the accompanying drawings. In the following description with reference to the accompanying drawings, the same or corresponding components are the same reference numerals. And duplicate description thereof will be omitted.

1 is a plan view showing an electroplating apparatus according to an aspect of the present invention, a wafer fixing device 11, an elastic pad 12, a metal foil 13, a cathode terminal 14, a sealing 15, a pressurized device ( A negative electrode assisting device 10, plating bath 20, positive electrode 21, plating liquid injector 22, shielding plate 23, plating liquid outlet 24 and wafer 30 including 16 are shown. .

An electroplating apparatus is a device for attaching a plating object to the cathode and a plating metal such as copper platinum to the anode to coat the plating metal on the surface of the object to be plated. When an electric current flows, the metal ions and electrons are separated from the anode. . Electrons move along the wire to the cathode, and metal ions are precipitated into the plating liquid. The metal ions separated from the positive electrode move to the negative electrode through a plating solution, which is an electrolyte, and in the negative electrode, electrons and metal ions received through a wire are combined to form an electrolytic plating on the surface of the plated object connected to the negative electrode.

The present embodiment relates to an electroplating apparatus for connecting a wafer 30 having a through hole to a cathode of a power supply and filling the through hole with a conductive material. The anode auxiliary device to which the anode 21 and the wafer 30 are fixed ( 10) and the positive electrode 21 and the negative electrode auxiliary device 10 is electrically connected.

The plating liquid injection device 22 may be provided to supply the plating liquid to the plating bath 20 containing the plating liquid, and to secure the fluidity of the ions to enable efficient plating. In particular, when the plating liquid is injected from the anode 21 toward the wafer 30, the metal ions separated from the anode 21 are easily moved toward the wafer 30.

Since the plating liquid is continuously supplied, the plating liquid outlet 24 can be formed to remove the plating liquid from the plating bath 20. It is also possible to repeatedly use the plating liquid drawn out through the plating liquid injection device 22 into the plating bath 20 again.

Since a high current density is formed at the edge of the wafer 30, there is a problem that the plating of the edge of the wafer 30 is formed thicker, so that the shielding plate 23 covering the edge of the wafer 30 is prevented. It may be further provided.

The negative electrode assisting device 10 is a device for fixing the wafer 30, which is the plated body of the electroplating, and electrically connecting the anode 21 and the wafer 30 so as to perform electroplating in the through hole. In the example, the wafer holding device 11, the elastic pad 12, the metal foil 13, the negative electrode terminal 14, the sealing 15, and the pressing device 16 are constituted.

Conventionally, an additional process was required by providing a base for plating by attaching a photoresist, an adhesive, or the like to one surface of the wafer 30. However, in this embodiment, without the additional process, it is possible to provide a negative electrode auxiliary device 10 that can be removed by applying a pressure in a physical method to close the metal foil 13, which is the base for plating, and to remove the pressure.

The elastic pad 12 includes an elastic member. When the elastic pad 12 is pressed in a direction facing the wafer 30 through the metal foil 13 between the wafer 30 and the elastic pad 12, the elastic pad 12 is elastic. Due to the elasticity of the pad 12, the wafer 30 and the metal foil 13 may be in close contact with each other without gaps. Examples of the elastic member include rubber, silicon, foamed silicon, and the like, and the size of the elastic pad 12 is equal to or larger than the size of the wafer 30 because the wafer 30 must be seated.

The metal foil 13 interposed between the wafer 30 and the elastic pad 12 is a base for plating the through-holes, and serves as a member that serves as copper, nickel, titanium, aluminum, gold, silver, and the like. have. The metal foil 13 is connected to the positive electrode 21 through the negative electrode terminal 14 and is integrated with the through electrode of the wafer 30 after plating is completed, so that the metal foil 13 can be separated and replaced from the negative electrode auxiliary device 10. The size of the metal foil 13 is sufficient if it can cover the part in which the through-hole of the wafer 30 was formed.

Next, the pressing device 16 presses the elastic pad 12 in the direction of the wafer 30 to serve to bring the metal foil 13 into close contact with the wafer 30.

The wafer holding device 11 for supporting the force of the pressing device 16 may be provided. That is, the wafer holding device 11 is in contact with the wafer 30 at the end of the wafer 30, and when the pressing device 16 presses the elastic pad 12, the wafer holding device 11 holds the wafer 30 at the other side of the wafer 30. I support it. In addition, if the sealing member 15, which is an elastic member, is further interposed in a portion in close contact with the wafer 30, the plating liquid may be prevented from leaking into the plating apparatus.

The negative electrode assisting device 10 may fix the wafer 30 by a physical crimping method at a position facing the anode 21 in the plating bath 20 to fill the through hole of the wafer 30 through electroplating. . A separate detachment process for closely contacting the metal foil 13 can be omitted, and thus damage to the wafer 30 due to thermal shock applied during detachment can be minimized.

Next, look at the wafer manufacturing method according to another aspect of the present invention.

3 is a flowchart illustrating a method for manufacturing a wafer through electrode according to another aspect of the present invention, and FIGS. 3 to 7 are flowcharts illustrating a method of manufacturing a wafer through electrode according to another aspect of the present invention. 3 to 7, a wafer 30, a through hole 31, a through electrode 34, a metal seed layer 32, a metal foil 13, and an elastic pad 12 are illustrated.

First, as shown in FIG. 3, a through hole 31 is formed in the wafer 30 (S100). The wafer 30 may be made of silicon, glass, pyrex, borosilicate, or the like, and the through hole 31 for forming the through electrode (34 of FIG. 7) may be formed of a laser. Drilling, reactive ion etching methods, chemical etching and the like can be used.

Next, as shown in FIG. 4, the metal seed layer 32 is formed on the inner wall surface of the through hole 31 on one side of the wafer (S200). Only the metal foil 13 may form the metal seed layer 32 in advance on the inner wall surface of the through hole 31 in order to secure the adhesion between the through hole 31 and the through electrode (34 in FIG. 6).

At this time, the metal seed layer 32 is formed on one surface of the wafer 30, that is, the surface where the wafer 30 and the metal foil 13 are in contact with each other. If the metal seed layer 32 is formed on the other side, the plating may be plated not only on one side but also on the other side, so that both ends of the through-hole 31 are blocked with an empty space (void) formed therein. In order to prevent such voids, the metal seed layer 32 is formed on the inner wall surface of the through hole 31 only on one surface side.

The metal seed layer 32 may use a metal such as titanium (Ti), ruthenium (Ru), copper (Cu), aluminum (Al), nickel (Ni), gold (Au), sputtering, physical vapor deposition, chemical The seed layer 32 can be formed by methods, such as a vapor deposition method.

Since the seed layer 32 must also be electrically connected through the metal foil 13, the seed layer also appears on the surface of one surface of the wafer 30 as shown in FIG. 4 to connect the metal foil 13 and the seed layer 32. 32 can be formed.

Next, as shown in FIG. 5, the metal foil 13 is physically compressed and fixed to one surface of the wafer 30 (S300). It should be tightly coupled so that the inlet hole 31 on one side of the wafer 30 is sealed. In the case of physically pressing and contacting, the wafer 30 is a material having no elasticity, and the metal foil 13 has a weak strength, which may deform or tear. Elastic pads 12 may be used to bring these two materials into close contact. Since the elastic pad 12 includes an elastic member, when the elastic pad 12 is pressed against the wafer 30 through the metal foil 13, the elastic pad 12 may closely contact the wafer 30 and the metal foil 13 without gaps.

Since the elastic pad has been described in detail in the description of the elastic pad 12 used in the electroplating apparatus described above, it will be replaced with this. The electroplating apparatus described above may be used for such close contact.

Next, the metal foil 13 and the anode are electrically connected to each other, and the through hole 31 is filled by electroplating (S400). The metal foil 13 is connected to the cathode corresponding to the anode, and the metal of the anode is plated on the metal foil 13 and the metal seed layer 32 through the through hole 31, and as shown in FIG. 6, the through hole ( 31) is filled with metal. Since the seed layer 32 is formed, an adhesive force with the inner wall surface of the through hole 31 is secured, and since there is a metal foil 12, no additional plugging operation is required.

After filling the through hole 31 to form the through electrode 34, the metal foil 13 is removed as shown in FIG. 7 to expose the through electrode on one surface (S500). Removing the metal foil 13 may be performed through chemical mechanical polishing.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It will be understood that the invention may be varied and varied without departing from the scope of the invention.

Many embodiments other than the above-described embodiments are within the scope of the claims of the present invention.

1 is a plan view showing an electroplating apparatus according to an aspect of the present invention.

Figure 2 is a flow chart showing a method for manufacturing a wafer through electrode according to another aspect of the present invention.

3 to 7 is a process flow diagram showing a wafer through electrode manufacturing method according to another aspect of the present invention.

<Description of the symbols for the main parts of the drawings>

10: cathode auxiliary device 11: wafer holding device

12: pad 13: metal foil

14: negative terminal 15: sealing

16: pressurizing device 20: plating bath

21: anode 22: plating liquid injector

23: shield plate 24: plating liquid outlet

30: wafer 31: through hole

32: metal seed layer 34: through electrode

Claims (9)

In the electroplating apparatus including a negative electrode auxiliary device and a positive electrode, to fill the through-holes of the wafer with a conductive material, The negative electrode auxiliary device, An elastic pad on which one side of the wafer is seated; A pressing device for pressing the elastic pad toward the wafer on the other surface of the elastic pad; And An electroplating apparatus including a metal foil interposed between the elastic pad and the wafer and replaceable and electrically connected to the anode. The method of claim 1, The elastic pad is electroplating apparatus characterized in that it comprises at least one of silicon, foamed silicone, rubber. The method of claim 1, Electrolytic plating apparatus further comprises a wafer holding device for fixing the wafer in contact with the end of the wafer. The method of claim 3, The wafer holding device further comprises an electrolytic sealing formed in the portion in contact with the wafer. Providing a wafer having through holes formed therein; Physically pressing and fixing the metal foil on one surface of the wafer; Electrically connecting the metal foil with a conductive material to be plated, and filling the through holes with the conductive material. The method of claim 5, The physical compression method Between the compression pad including the elastic member and the wafer And pressing the pressing pad in the direction of the wafer via the metal foil. The method of claim 5, Before fixing the metal foil, And forming a metal seed layer on an inner wall of the through hole on one side of the wafer. The method of claim 7, wherein The metal seed layer is Wafer through electrode manufacturing method, characterized in that further formed on the one surface of the wafer. The method of claim 5, After filling the through hole Wafer through electrode manufacturing method characterized in that it further comprises the step of removing the metal foil.

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