JP2002521575A - Electroplating system for conductive pattern and electroplating method thereof - Google Patents

Abstract

The present invention provides a method and system for plating a conductive pattern that provides at least a high degree of uniformity and avoids parasitic plating effects. A plating system for plating a conductive pattern formed on a first surface of a substrate is disclosed. This system prevents exposure to surfaces that should not be plated. The first electrode of the system is immersed in the plating solution while the second electrode is in contact with something other than the first surface of the substrate. The conductive pattern to be plated is temporarily electrically connected to the second electrode. Substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method and a system for electroplating a conductive pattern.

BACKGROUND ART In the solid-state electronic industry, not only active devices but also electronic components such as passive devices are processed on the surface of a semiconductor wafer when forming an integrated circuit, for example. The formation of such integrated circuits requires metallized structures to be part of the aforementioned devices and to connect these devices. Forming such a metallized structure comprises electroplating a conductive pattern formed on a first surface of a substrate, such as a wafer, as part of the metallized structure. Note that this first surface of the substrate may be the front surface of the wafer or the back surface.

One of the problems here is that the first surface of the substrate, which is opposite to the first surface, is subjected to electrolytic plating without being exposed to an electrolytic plating solution. . Such exposure is undesirable because other surfaces may get wet, adhere, or corrode. Also, in order to allow the material to be deposited by electroplating, the electroplating solution must be in contact with the first surface of the substrate comprising the conductive pattern to be electroplated, and the two electrodes that can be electrically connected It is necessary to provide. Generally, a first surface is immersed in an electroplating solution and a second surface is electrically connected to a conductive pattern to be electroplated. In a conventional electrolytic plating method, a peripheral portion of a first surface of a substrate having a conductive pattern to be electroplated is in contact. Usually, these peripheral contact portions are electrically connected not only to the second electrode but also to a conductive pattern to be electroplated.

However, there is a problem in that a long metal wire is required to connect each conductive pattern to be plated to a peripheral contact. In particular, since the difference in distance between the conductive pattern to be plated near the edge of the wafer and the conductive pattern to be plated in the center of the wafer is very large, there is a problem when performing electrolytic plating on a wafer scale. is there. These differences are generally of the order of centimeters. Therefore, the difference in resistance between the metal wires connecting the conductive patterns becomes very large. This often results in a very uneven electrolysis process. The metal connection between the conductive pattern to be plated and the periphery is
It cannot be easily removed after the completion of electrolytic plating, and a wafer having a large area is required to achieve such connection, which hinders high density. Another problem is that the peripheral contact means is exposed to the electrolytic plating solution. In this case, the contact means is parasitically plated and needs to be periodically cleaned. Further, when the contact means is not used as the sealing means at the same time, there is a problem that a separate sealing means is required. These sealing means need to be located between the contact means and the edge of the wafer to avoid leakage of the plating solution to other surfaces of the wafer. Therefore, the area that can be plated is further reduced.

DISCLOSURE OF THE INVENTION Technical Problem to be Solved The present invention provides a method for electrolytic plating a conductive pattern having at least a high degree of uniformity and capable of avoiding a parasitic plating effect. System.

(Solution) In one aspect of the present invention, there is disclosed an electrolytic plating system for plating a plurality of conductive patterns formed on a surface of a substrate. A plating solution is applied to this surface to prevent other surfaces of the substrate from being exposed to the plating solution. The first electrode of the system is immersed in the plating solution while the second electrode is in contact with another surface of the substrate. Since the conductive pattern to be plated is temporarily electrically connected to the second electrode, it is uniformly and selectively attached to the exposed surface of the substrate. In particular, according to the invention according to this aspect, there is disclosed a system for plating at least one conductive pattern positioned on a first surface of a substrate having at least a first surface and a second surface,
The system comprises a support having electrically connectable electrodes, and a sealing element for preventing exposure of a second surface of the substrate to a plating solution, such that the electrodes contact the second surface of the substrate. The base can be placed on the support, and a contact with the first surface of the substrate is provided, and the conductive pattern is temporarily electrically connected to the contact, The contact is configured to be electrically connected to the electrode.

According to another aspect of the invention, a substrate having at least a first surface adapted to be exposed to a plating solution and a second surface opposite the first surface, the substrate comprising: A conductive pattern positioned on the first surface, and a contact with the first surface of the substrate, wherein the conductive pattern is temporarily electrically connected to the contact via a polysilicon or amorphous silicon conductor. A substrate is disclosed in which the contact is electrically connected to the second surface.

According to another aspect of the present invention, there is provided a method of plating at least one conductive pattern formed on a surface of a substrate having at least a first surface and a second surface, the method comprising: Placing a substrate on an electrode that is part of a plating holder, such that the second surface is in contact with the electrode and the conductive pattern is temporarily electrically connected to the conductive pattern; Applying a plating solution to said first surface to prevent exposure of said second surface to said plating solution.

BEST MODE FOR CARRYING OUT THE INVENTION In one aspect, the present invention discloses an electroplating system for plating a plurality of conductive patterns formed on a surface of a substrate. A plating solution is applied to this surface to prevent other surfaces of the substrate from being exposed to the plating solution. The first electrode of the system is immersed in the plating solution while the second electrode is in contact with another surface of the substrate. Since the conductive pattern to be plated is temporarily electrically connected to the second electrode, it is uniformly and selectively attached to the exposed surface of the substrate. In particular, according to the invention according to this aspect, there is disclosed a system for plating at least one conductive pattern positioned on a first surface of a substrate having at least a first surface and a second surface, the system comprising: A support having electrodes that can be electrically connected; and a sealing element for preventing the second surface of the substrate from being exposed to a plating solution, wherein the base is placed such that the electrodes are in contact with the second surface of the substrate. The support can be placed on the support, and a contact with the first surface of the substrate is provided, the conductive pattern is temporarily electrically connected to the contact, and the contact is It is configured to be electrically connected to the electrodes. In particular, the electrical connection between the contact on the first surface of the substrate and the electrode on the second surface of the substrate may be made from a doped semiconductor region, either n-type or p-type, or from the first surface of the substrate. It may be a metal via connection extending to the second surface. Also, a metal contact may be provided on the second surface of the substrate.

In a preferred embodiment of the present invention, a system for plating a plurality of conductive patterns formed on a surface of a substrate is disclosed. Each conductive pattern to be plated is temporarily electrically connected to a contact to the first surface of the substrate via a polysilicon or amorphous silicon conductor. In particular, the conductive pattern is positioned on a first die, and the corresponding contacts are positioned on a second die separate from said first die. Preferably, the second die is close to the first die and the polysilicon or amorphous silicon conductor is made as short as possible to minimize the resistance of the connection. Thereby, plating can be performed almost uniformly.

In another embodiment of the present invention, there is provided a system for plating a plurality of conductive patterns formed on a surface of a substrate, the system comprising: a contact between at least a portion of the conductive pattern and a first surface of the substrate. A system is disclosed in which either or both are coated with a layer that prevents the portion from being plated. In particular, this layer may be a resist layer. In this way, plating, which is generally undesirable, on the contact to the first surface of the substrate can be avoided.

The substrate may be made of a conductive material, or may be made of a doped semiconductor material. In particular, an n-type or p-type silicon semiconductor wafer can be used. Any plating solution may be used as long as it is commercially available. In particular, Ag, Cu, Au, Pt, Ti
, Ni, and a plating solution containing an element selected from the group consisting of Co are preferable. The conductive pattern is usually a metal pattern. In particular, an Al-containing or Cu-containing pattern can be used.

In another aspect of the invention, a substrate having at least a first surface adapted to be exposed to a plating solution and a second surface opposite the first surface, wherein A conductive pattern positioned on the first surface, and a contact with the first surface of the substrate, wherein the conductive pattern is temporarily electrically connected to the contact via a polysilicon or amorphous silicon conductor; A substrate having the contact electrically connected to the second surface is disclosed.

According to another aspect of the present invention, there is provided a method of plating at least one conductive pattern formed on a surface of a substrate having at least a first surface and a second surface, the method comprising: Placing a substrate on an electrode that is part of a plating holder, such that the second surface is in contact with the electrode and the conductive pattern is temporarily electrically connected to the conductive pattern; Applying a plating solution to said first surface to prevent exposure of said second surface to said plating solution.

[0015] In another embodiment of the present invention, a plating solution is disclosed, wherein a polysilicon or non-conductive material temporarily connects a conductive pattern formed on a first surface of a substrate with a contact to the substrate. A crystalline silicon conductor is formed, and an electrical connection is provided between the contact and the electrode to temporarily electrically connect the electrode and the conductive pattern.
The resistance of the electrical connection between the contact and the electrode is substantially independent of the position of the contact on the first surface of the substrate. Therefore, in order to obtain a high degree of uniformity across the substrate in the plating operation, it is desirable to minimize the length of the polysilicon or amorphous silicon conductor. On the other hand, it is easy to break the connection formed by the silicon or amorphous silicon conductor after the plating operation. Therefore, it is preferable that the conductive pattern is positioned on the first die and the contact is positioned on the second die different from the first die. By doing so, the connection portion can be cut at the time of dicing the substrate. More preferably, the first and second dies are close to each other.

In another embodiment of the present invention, a resist layer is provided on the conductive pattern before applying the plating solution, and the resist layer is provided with at least one coating portion,
A method is disclosed for patterning to form at least one uncoated portion that can be exposed to a plating solution.

In the embodiments of the present invention, as an example, a system and a method for selectively performing electrolytic plating on a plurality of aluminum patterns are disclosed. The aluminum pattern to be plated is formed on the front surface of a silicon wafer having p-type conductivity. Each aluminum pattern to be plated (FIG. 1) is connected via a polysilicon line to an aluminum contact to the p-type substrate region of the wafer on the front side of the wafer. This contact is provided on an adjacent die. The polysilicon line is insulated from the wafer via at least one dielectric. This polysilicon line extends along the dicing line (FIG. 2). Thus, all aluminum patterns to be plated are electrically connected to the backside of the wafer, which may be provided with aluminum metal contacts.

Prior to applying the plating solution, the wafer is placed on a support having electrodes that can be electrically connected so that the back surface of the wafer and the electrodes are electrically connected. This support is
It is a part of a wafer holder devised so as to be suitable for a plating operation. During the plating operation, the plating solution is brought into contact with the front surface of the wafer, while the back surface is sealed with a sealing element constituting a part of the wafer holder (FIG. 3). In particular, the sealing element is a sealing ring that prevents the backside of the substrate from being exposed to the plating solution. The back surface of the wafer is electrically connected to a back electrode of the same size. By immersing a similar electrode as the counter electrode in the plating solution, a homogeneous electric field is created. In the plating operation, the current is kept constant by a constant current electrolytic plating method, for example, by adjusting the potential between the back electrode and the counter electrode. According to this example, silver is electrolytically plated, and an alkaline silver solution is used as a plating solution.
A negative potential is applied to the back electrode.

In order to avoid plating on the aluminum contact to the substrate on the front surface of the substrate, a positive photoresist layer (AZ4562) is used to cover an area where plating does not occur.

Finally, the wafer is peeled off and diced. 4 and 5 show a cross-sectional view and a top view, respectively, of a polysilicon line. By dicing the polysilicon lines, the electrolytically plated structures are separated from their respective substrate contacts.

By using the substrate as a contact layer for the electrodes, the electrical resistance between the area to be plated and the electrical contacts is increased over all the plated structures, in particular the length of the polysilicon line. Can be made substantially the same by making the resistance of the polysilicon line sufficiently short and the resistivity of the polysilicon line sufficiently low. This length must be short enough so that the resistance of the polysilicon line is negligible to the total resistance of the connection between the conductive pattern and the backside of the wafer. No. Therefore, the uniformity of the plating operation can be increased. If reduced, the uniformity of the adhesion thickness of the plated material over the entire wafer can be increased. In this example, the plated material is silver.

By dicing over the polysilicon lines, the individual electroplated patterns are separated from one another and are no longer in contact with the substrate. Utilizing polysilicon or amorphous silicon lines extending across the dicing lines can reduce the likelihood of forming an electrolytic plating pattern that will short circuit with the substrate after dicing. If metal or lead wires are used to form connections to contacts that extend across the dicing line, the electroplated pattern will remain in contact with the substrate even after dicing due to metal chips and residues. It may be.

The same plating application system and method as described above according to the invention uses a different solution,
If a positive potential is applied to the back electrode instead of the negative potential, it can be used for wafer-scale electrochemical chloridation. In particular, it is suitable for electrochemical chlorination of silver. Electrochemical chlorination of bulk silver electrodes (wires) can be used to form standard reference electrodes. The advantage is that the quality of the AgCl layer formed using the electrochemical chlorination method is better than that formed using the chemical chlorination method. Thus, according to the present invention, a wafer-scale Ag / AgCl reference electrode is formed by electroplating silver and electrochemically chloridized silver.
chloride).

[Brief description of the drawings]

FIG. 1 shows a plurality of structures to be plated. Each structure (with boundary (2)) is connected to a polysilicon stripe crossing the dicing line (1).

FIG. 2 shows a first die metal (3) and a second die in close proximity to each other. A polysilicon stripe (4) extends from the metal (3) over the dicing line (1) and is connected to a substrate contact (5) on the second stage.

FIG. 3 shows a plating system comprising a plating holder with a back contact. Sealing means (6) are visible which prevent the second surface of the wafer from being exposed to the plating solution. There is also a back contact means.

FIG. 4 shows a cross-sectional view of a polysilicon stripe. Dicing across the polysilicon stripe separates the electroplated structure from the substrate contacts.

FIG. 5 shows a top view of a polysilicon stripe.

[Procedural Amendment] Submission of translation of Article 34 Amendment of the Patent Cooperation Treaty

[Submission date] August 31, 2000 (2000.8.31)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

──────────────────────────────────────────────────続 き Continuation of front page (81) Designated country EP (AT, BE, CH, CY, DE, DK, ES, FI, FR, GB, GR, IE, IT, LU, MC, NL, PT, SE ), OA (BF, BJ, CF, CG, CI, CM, GA, GN, GW, ML, MR, NE, SN, TD, TG), AP (GH, GM, KE, LS, MW, SD, SL, SZ, UG, ZW), EA (AM, AZ, BY, KG, KZ, MD, RU, TJ, TM), AE, AL, AM, AT, AU, AZ, BA, BB, BG, BR , BY, CA, CH, CN, CU, CZ, DE, DK, EE, ES, FI, GB, GD, GE, GH, GM, HR, HU, ID, IL, IN, IS , JP, KE, KG, KP, KR, KZ, LC, LK, LR, LS, LT, LU, LV, MD, MG, MK, MN, MW, MX, NO, NZ, PL, PT, RO, RU, SD, SE, SG, SI, SK, SL, TJ, TM, TR, TT, UA, UG, US, UZ, VN, YU, ZA, ZW (72) Inventor Philip van Steinkiste Belgium, Bö-9870 Machelen, Hufestraat 12 (72) Inventor Chris Beert Belgium, Bée-3001 Louvain, Sint-Jörisland 9 (72) Inventor Walter Gumbrecht Germany Day 91074 Herzoge Naurach, In Der Rote No. 1 (72) Inventor Filippe Alkwind Germany Day-91074 Herzoge Naurach, Stegerstr. None (reference) 4K024 AA01 AA03 AA09 AA10 AA11 AA12 AB01 BA06 BA09 BB12 BC10 CB26 FA07 FA08 GA16 4M104 BB04 BB05 BB06 BB08 BB09 BB14 DD52

Claims (14)

[Claims] 1. A system for plating at least one conductive pattern positioned on a first surface of a substrate having at least a first surface and a second surface, comprising: a support having electrically connectable electrodes; A sealing element for preventing exposure of the second surface of the substrate to the plating solution, wherein the substrate can be placed on the support such that the electrode contacts the second surface of the substrate. Also, a plating system is provided, wherein a contact with the first surface of the substrate is provided, the conductive pattern is temporarily electrically connected to the contact, and the contact is electrically connected to the electrode. 2. The method of claim 1, wherein the conductive pattern is temporarily electrically connected to the contact to the first surface of the substrate via a polysilicon conductor or an amorphous silicon conductor. A plating system consisting of: 3. The method according to claim 2, wherein the conductive pattern is positioned on a first die, and the contact is positioned on a second die different from the first die. Plating system. 4. The plating system according to claim 1, wherein a part of the conductive pattern on the first surface is covered with a resist layer to prevent the part from being plated. 5. The plating system according to claim 1, wherein the substrate is made of a conductive material or a doped semiconductor material. 6. The plating system according to claim 1, wherein a metal contact is provided on the second surface of the substrate. 7. The method according to claim 1, wherein the plating solution is Ag,
A plating system comprising an element selected from the group consisting of Cu, Au, Pt, Ti, Ni, and Co. 8. At least a first surface adapted to be exposed to a plating solution;
A substrate having a second surface opposite to the first surface, comprising: a conductive pattern positioned on the first surface of the substrate; and a contact point with the first surface of the substrate; Is electrically connected to the contact via a polysilicon or amorphous silicon conductor, and the contact is electrically connected to the second surface. 9. A method for plating at least one conductive pattern formed on a surface of a substrate having at least a first surface and a second surface, wherein the second surface of the substrate contacts the electrode. Placing a substrate on an electrode that is part of a plating holder so that the conductive pattern is temporarily electrically connected to the conductive pattern; and applying a plating solution to the first surface of the substrate. And preventing the second surface from being exposed to the plating solution. 10. The method according to claim 10, wherein the electrode and the conductive pattern are polysilicon that temporarily connects the conductive pattern formed on the first surface of the substrate to a contact to the substrate. A plating method comprising forming an amorphous silicon conductor and providing an electrical connection between the contact and the electrode to temporarily make an electrical connection. 11. The plating method according to claim 10, wherein the conductive pattern is positioned on a first die, and the contact is positioned on a second die different from the first die. 12. The plating method according to claim 11, further comprising a step of dicing the substrate after plating the conductive pattern. 13. The method according to claim 9, wherein a resist layer is provided on the conductive pattern before applying the plating solution, and the resist layer is exposed to at least one coating portion and the plating solution. A plating method comprising patterning to form one uncoated portion. 14. The method according to claim 9, wherein the plating solution is Ag.
, Cu, Au, Pt, Ti, Ni, and a plating method comprising an element selected from the group consisting of Co.