JP6169500B2 - Electroless plating method, electroless plating apparatus and storage medium - Google Patents

Description

  The present invention relates to an electroless plating method, an electroless plating apparatus, and a storage medium for forming an electroless plating layer on a substrate.

  Metal formation in the LSI manufacturing process is performed by growing the entire surface of the substrate by CVD or PVD. For metal shape processing, in the past, etching with chemicals, dry etching of Al wiring, and in the recent BEOL process, the insulating film is first dry etched, and the inside of the formed groove or the like is used for wiring such as Cu. Metal shape processing is performed by a method such as embedding metal and etching by CMP (Patent Document 1).

  In such metal shape processing, a substrate is first prepared, a plurality of metal layers are formed on the substrate by PVD or CVD, and a resist pattern is provided on the plurality of metal layers to form a plurality of layers. A method of etching the metal layer is employed.

  However, when a plurality of thick metal layers are formed on a metal and then a plurality of metal layers are dry etched together, the current dry etching takes time and the load of the etching process is increased. Also, depending on the metal (for example, Cu), dry etching itself is very difficult, and etching cannot be performed with high accuracy, and it is difficult to form a plurality of metal layers patterned with high accuracy on a substrate.

Japanese Patent Laid-Open No. 11-297699

  The present invention has been made in consideration of such points, and a metal layer patterned with high precision is reliably formed on a substrate, and a metal layer that does not require shape processing by dry etching is formed on the metal layer. An object of the present invention is to provide an electroless plating method, an electroless plating apparatus, and a storage medium.

  The present invention relates to an electroless plating method for performing electroless plating on a substrate on which a patterned first metal layer made of a metal compound having no catalytic property and a metal sacrificial layer are sequentially formed. A step of forming a catalyst layer on the metal sacrificial layer by applying an aqueous solution containing an ionized metal that can replace the metal of the layer on the metal sacrificial layer, and applying electroless plating on the catalyst layer An electroless plating method characterized by comprising a step of forming a second metal layer.

  The present invention provides an electroless plating apparatus for applying an electroless plating layer to a substrate on which a patterned first metal layer made of a metal compound having no catalytic property and a metal sacrificial layer are sequentially formed. A catalyst layer forming portion for forming a catalyst layer on the metal sacrificial layer by applying an aqueous solution containing an ionized metal that can replace the metal of the sacrificial layer on the metal sacrificial layer, and electroless on the catalyst layer An electroless plating apparatus including a second metal layer forming unit that forms a second metal layer by plating.

  The present invention relates to a storage medium storing a program for causing a computer to execute an electroless plating method. The electroless plating method includes a patterned first metal layer made of a metal compound having no catalytic property, and a metal sacrificial layer. An electroless plating method for performing electroless plating on a substrate on which layers are sequentially formed, wherein an aqueous solution containing an ionized metal that can replace a metal of the metal sacrificial layer is applied onto the metal sacrificial layer Thus, there is provided a storage medium comprising a step of forming a catalyst layer on the metal sacrificial layer and a step of forming a second metal layer by performing electroless plating on the catalyst layer.

  According to the present invention, a plurality of metal layers patterned with high precision can be easily and reliably formed on a substrate.

1A to 1F are flowcharts showing an electroless plating method in the present invention. FIG. 2 is a block diagram showing an electroless plating apparatus according to the present invention. FIGS. 3A and 3B are diagrams showing a multilayer metal layer forming method as a comparative example.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1A, 1B, 1C, 1D, 1E, and 1F, a metal layer forming method according to the present invention is applied to a silicon substrate 11 (hereinafter also referred to as a substrate) 11 made of a semiconductor wafer or the like. On the other hand, the 1st metal layer 12, the metal sacrificial layer 15, the catalyst layer 16, and the electroless-plating layer 18 are formed in order. Note that the total thickness of the metal layer obtained by sequentially forming the first metal layer 12, the metal sacrificial pseudo control layer 15, the catalyst layer 16, and the electroless plating layer 18 is shown in FIG. A metal layer having the same thickness as the entire metal layer obtained by forming the first metal layer 12 and the second metal layer 18 is formed.

  In this case, a substrate body made of Si can be used as the substrate 11, or a substrate having a substrate body made of Si and a TEOS layer provided on the substrate body may be used.

  Next, an electroless plating apparatus 30 that sequentially forms the first metal layer 12, the metal sacrificial layer 15, the catalyst layer 16, and the electroless plating layer 18 on the substrate 11 will be described with reference to FIG.

  Such an electroless plating apparatus 30 includes a first metal layer forming portion 31 for forming a first metal layer 12 made of a metal compound having no catalytic property on the substrate 11, and a metal sacrifice on the first metal layer 12. A metal sacrificial layer forming portion 32 for forming the layer 15 and an aqueous solution containing an ionized metal that can replace the metal of the metal sacrificial layer 15 are applied onto the metal sacrificial layer 15, thereby forming a metal sacrificial layer 15 on the metal sacrificial layer 15. A catalyst layer forming portion 33 for forming the catalyst layer 16 and a second metal layer forming portion 34 for forming the second metal layer 18 by performing electroless plating on the catalyst layer 16 are provided.

  Further, an etching unit 35 that etches the substrate 11 using the second metal layer 18 as a mask and performs patterning on the substrate 11 is provided after the catalyst layer forming unit 33 and the second metal layer forming unit 34.

  Further, each component of the electroless plating apparatus 10 described above, for example, the first metal layer forming part 31, the metal sacrificial layer forming part 32, the catalyst layer forming part 33, the second metal layer forming part 34, and the etching part 35 are all included. Drive control is performed by the control device 40 in accordance with various programs recorded in the storage medium 41 provided in the control device 40, whereby various processes are performed on the substrate 11. Here, the storage medium 41 stores various setting data and various programs such as a metal layer forming program described later. As the storage medium 41, a known medium such as a computer-readable memory such as ROM or RAM, or a disk-shaped storage medium such as a hard disk, CD-ROM, DVD-ROM, or flexible disk can be used.

  Next, the operation of the present embodiment having such a configuration will be described with reference to FIG.

  First, the substrate 11 made of a semiconductor wafer or the like is transferred to the electroless plating apparatus 30.

  In this case, the surface of the substrate 11 may be flat (see FIG. 1A), or a recess may be formed on the surface of the substrate 11.

  Here, as a method of forming the concave portion in the substrate 11, a conventionally known method can be appropriately employed. Specifically, for example, as a dry etching technique, a general-purpose technique using a fluorine-based or chlorine-based gas or the like can be applied. In particular, a hole having a large aspect ratio (hole depth / hole diameter) is formed. Can adopt the method which adopted the technique of ICP-RIE (Inductively Coupled Plasma Reactive Ion Etching: Inductively Coupled Plasma-Reactive Ion Etching) capable of high-speed deep etching, more particularly, sulfur hexafluoride ( A method called a Bosch process in which an etching step using SF6) and a protection step using a Teflon-based gas such as C4F8 are repeated can be suitably employed.

  Next, in the electroless plating apparatus 30, the substrate 11 is sent to the first metal layer forming unit 31. In the first metal layer forming portion 31, the patterned first metal layer 12 is formed on the substrate 11.

  Specifically, as shown in FIG. 1A, a first metal layer 12 made of TiN or TaN is formed on a substrate 11 by CVD or PVD. These TiN or TaN is a metal compound that does not have catalytic properties for the second metal layer 18 formed by electroless plating described later.

  Next, the substrate 11 on which the first metal layer 12 is formed is sent to the metal sacrificial layer forming portion 32, and the metal sacrificial layer 15 is formed on the first metal layer 12 in the metal sacrificial layer forming portion 32 (FIG. 1 (b)).

  The metal sacrificial layer 15 includes a metal that can replace the metal constituting the catalyst layer 16 described later, and is formed on the first metal layer 12 by CVD or PVD in the metal sacrificial layer forming portion 32.

  The metal sacrificial layer 15 may be formed as a film thinner than the first metal layer 12 continuously connected to the first metal layer 12. Further, it may be formed as a discontinuous film on the first metal layer 12 or may be formed in a granular form. The thickness of the metal layer composed of the first metal layer 12 and the metal sacrificial layer 15 is made thinner than the metal layer composed of the first metal layer 12 and the second metal layer 18 of FIG.

  Next, a resist pattern 13 is provided on the first metal layer 12 and the metal sacrificial layer 15, and patterning is performed by etching the first metal layer 12 and the metal sacrificial layer 15 provided with the resist pattern 13. Thus, the first metal layer 12 and the metal sacrificial layer 15 are obtained (see FIG. 1C). Thereafter, the resist pattern 13 is removed from the first metal layer 12 and from the metal sacrificial layer 15 (see FIG. 1D).

  Any of Ti, W, Cu, Ni, and Co can be used as the metal constituting the metal sacrificial layer 15.

  Next, the substrate 11 on which the metal sacrificial layer 15 is formed on the first metal layer 12 is then sent to the catalyst layer forming unit 33. Next, in the catalyst layer forming unit 33, an aqueous solution containing ionized metal that can replace the metal of the metal sacrificial layer 15 is applied to the metal sacrificial layer 15 on the substrate 11, thereby Thus, the catalyst layer 16 is formed (see FIG. 1E).

  Specifically, when the metal sacrificial layer 15 is made of Ti or W, an aqueous solution such as a Pd chloride solution or a Pd sulfate solution is applied to the metal sacrificial layer 15. In this case, Pd ions in the aqueous solution are replaced with Ti or W of the metal sacrificial layer 15, and Pd ions break out on the metal sacrificial layer 15.

  In this way, the catalyst layer 16 made of any one of Pd, Au, and Pt can be formed on the metal sacrificial layer 15.

  Next, the substrate 11 on which the surface catalyst layer 16 is formed is sent to the second metal layer forming unit 34, and the second metal layer forming unit 34 performs electroless plating on the substrate 11 to form the second metal layer. 18 is formed.

  Specifically, by performing electroless plating of Ni metal on the substrate 11, plating using the Pd metal of the catalyst layer 16 as a catalyst is performed on the substrate 11, and second plating is performed on the catalyst layer 16 with Ni metal. A metal layer 18 is formed (see FIG. 1 (f)).

  At this time, the second metal layer 18 formed by electroless plating has a thickness equivalent to the thickness of the metal layer formed of the first metal layer 12 and the second metal layer 18 in FIG. To form. The second metal layer 18 formed according to the present invention is selectively formed only on the patterned metal layer.

  Note that the second metal layer forming unit 34 may form the second metal layer 18 made of Cu metal on the catalyst layer 16 by performing electroless plating using Cu metal without using Ni metal.

  Next, the substrate 11 on which the second metal layer 18 is formed is sent to the etching unit 35, and the etching is performed on the substrate 11 using the second metal layer 18 as a mask (see FIG. 5). 1 (g)).

  As described above, according to the present embodiment, after the first metal layer 12 and the metal sacrificial layer 15 are formed on the substrate 11, the first metal layer 12 and the metal sacrificial layer 15 are etched using the resist pattern 13. The catalyst layer 16 can be provided on the first metal layer 12 and the metal sacrificial layer 15 that have been applied and patterned, and then the second metal layer 18 can be provided by electroless plating using the catalyst layer 16. Thus, dry etching using the resist pattern 13 can be performed on the thin metal layers of the first metal layer 12 and the metal sacrificial layer 15, reducing the load of the etching process, and accurately patterning the first metal layer. 12 and the second metal layer 18 can be formed. Further, as compared with the case where a metal layer is formed on the entire surface of the substrate 11 by CVD or PVD, the second metal layer 18 is selectively selectively formed only on the patterned first metal layer 12 and metal sacrificial layer 15 via the catalyst layer 16. Can be formed.

  Next, a comparative example for the present invention will be described with reference to FIGS. As shown in FIGS. 3A and 3B, when a multilayer metal layer is provided on the substrate 11, the first metal layer 12 made of TiN or TaN and the second metal made of Ni are formed on the substrate 11 by CVD or PVD. It is also possible to form the patterned first metal layer 12 and second metal layer 18 by forming the layer 18 and then providing the resist pattern 23 on the second metal layer 18 and etching. .

  However, in FIGS. 3A and 3B, the thick metal layers of the first metal layer 12 and the second metal layer 18 on the substrate 11 need to be etched together, and the current dry etching takes time, etc. Therefore, it is difficult to form the first metal layer 12 and the second metal 18 patterned with high accuracy.

  On the other hand, according to the present embodiment, it is possible to reduce the load of the etching process and obtain the first metal layer 12 and the second metal layer 18 that are accurately patterned.

  In the present embodiment, the second metal layer 18 is used as a mask for etching the substrate 11. However, the present invention is not limited to this, and the second metal layer 18 is adjusted to a necessary thickness. Can be used as device wiring.

11 substrate 12 first metal layer 13 resist pattern 15 metal sacrificial layer 16 catalyst layer 18 second metal layer 23 resist pattern 30 electroless plating apparatus 31 first metal layer forming part 32 metal sacrificial layer forming part 33 catalyst layer forming part 34 Two metal layer forming part 35 Etching part 40 Control device 41 Storage medium

Claims (6)

In an electroless plating method in which a first metal layer and a replaceable metal layer are sequentially formed, and electroless plating is performed on a substrate on which the first metal layer and the replaceable metal layer are patterned,
Forming the first metal layer on the substrate;
Forming the replaceable metal layer on the first metal layer;
Forming a resist pattern on the replaceable metal layer;
Etching the first metal layer and the replaceable metal layer through a resist pattern;
Removing a resist pattern from the replaceable metal layer;
A catalyst layer is formed only on the patterned first metal layer and the replaceable metal layer by applying an aqueous solution containing an ionized metal replaceable with the metal of the replaceable metal layer onto the replaceable metal layer. Forming a step;
A step of forming a second metal layer by performing electroless plating on the catalyst layer;
The first metal layer is a metal compound having no catalytic property with respect to the second metal layer,
The substitutable metal layer is a metal layer for causing a substitution reaction with the ionized metal in the aqueous solution and folding out the ionized metal on the substitutable metal layer, and the first metal layer Formed thinner,
The electroless plating method, wherein the catalyst layer is a metal formed by folding an ionized metal in the aqueous solution.   The electroless plating method according to claim 1, wherein the metal compound of the first metal layer is made of TiN or TaN.   3. The electroless plating method according to claim 1, wherein the metal of the replaceable metal layer is made of Ti, W, Cu, Ni, or Co.   The electroless plating method according to any one of claims 1 to 3, wherein the metal of the catalyst layer is made of Pd, Au, or Pt.   The electroless plating method according to claim 1, wherein the second metal layer is made of an electroless plating layer of Ni. In a storage medium storing a program for causing a computer to execute an electroless plating method,
The electroless plating method is an electroless plating method in which a first metal layer and a replaceable metal layer are sequentially formed, and electroless plating is performed on a substrate on which the first metal layer and the replaceable metal layer are patterned. In
Forming the first metal layer on the substrate;
Forming the replaceable metal layer on the first metal layer;
Forming a resist pattern on the replaceable metal layer;
Etching the first metal layer and the replaceable metal layer through a resist pattern;
Removing a resist pattern from the replaceable metal layer;
A catalyst layer is formed only on the patterned first metal layer and the replaceable metal layer by applying an aqueous solution containing an ionized metal replaceable with the metal of the replaceable metal layer onto the replaceable metal layer. Forming a step;
A step of forming a second metal layer by performing electroless plating on the catalyst layer;
The first metal layer is a metal compound having no catalytic property to the second metal layer,
The substitutable metal layer is a metal for causing a substitution reaction with the ionized metal in the aqueous solution and folding the ionized metal on the substitutable metal layer, and from the first metal layer Thinly formed,
The storage medium according to claim 1, wherein the catalyst layer is a metal obtained by folding an ionized metal in the aqueous solution.

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