JPH03202499A - Controlling method for thickness of plated film - Google Patents

Abstract

PURPOSE:To control thickness of a plated film while indirectly and realtimely measuring it by providing a plating part for measuring thickness of the plated film as an integral body or a separated body for the member to be plated and measuring the electric resistance of the plated film which is coated to this plating part in a plating stage. CONSTITUTION:A coil is formed by providing a photoresist 4c having a coil pattern 4b on the surface of a wafer 4 and arranging the wafer 4 to the inside of a plating device and impressing plating current from the introduction parts 4d and coating a conductive film on a sealing layer. A plating part 4e for measuring thickness of a plated film is provided on the wafer 4. The resistance between the terminals 4e1, 4e2 of the plated film coated to this plating part 4e is measured in a plating stage. Thickness of the plated film is controlled on the basis of the measured value of this resistance while indirectly and realtimely measuring thickness of the film plated on the wafer 4.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a method for controlling the thickness of a plating film when, for example, a coil of a thin film magnetic head is formed by photolithography technology, plating technology, etc. By measuring the electrical resistance of the conductive material during the plating process, we can indirectly measure the coating thickness of the plated member in real time and control the coating thickness. In the plating process, a plating part for measuring the plating film thickness is provided either integrally or separately from the part to be coated, and the electrical resistance of the coating film applied to this measuring part is measured during the coating process. The present invention is characterized in that the thickness of the plating film plated on the member to be plated is controlled while indirectly measuring the thickness of the plating film.

[Industrial application field]

The present invention relates to a method for controlling the thickness of a plating film when, for example, a coil of a thin-film magnetic head is formed using photolithography technology, plating technology, or the like.

[Conventional technology]

In recent years, with the demand for faster and smaller computer systems, magnetic disk drives are also required to be faster, larger capacity, and smaller. For this reason, the
The R-film magnetic hen is required to have high recording density and high performance, and it is required to manufacture it with high yield.

As a requirement for this, for example, it is necessary to keep the electrical resistance of the coil of the thin-film magnetic head relatively low and constant, and to make the electromagnetic conversion characteristics constant.

For example, it is known that even if a constant current is passed through the coil, if the electrical resistance of the coil changes, the heat generation will change due to I2R, and the amount of thermal noise will change accordingly.

There are various methods for forming the coil of the thin-film magnetic hend as described above, such as plating, sputtering, and vapor deposition, but the one most commonly used at present is the Menki method as shown in FIG.

In this figure, l is a plating tank, 2 is an anode electrode placed in plating solution 3, and 4 is a plated member placed in plating solution 3. A wafer (base 1) on which a seed layer 4a is attached.

When the seed layer 4a of this wafer 4 is connected to one pole of the DC power source 5, and the anode electrode 2 is connected to a half pole of the DC type a5, and a current is applied, metal ions in the plating solution 3 are transferred to the seed layer 4a. adhere to. Note that 6 is an ammeter for measuring the plating current.

When forming a coil on the wafer 4 using such a plating technique, as shown in FIGS. A photoresist 4C is attached leaving the portion . Such a coil pattern may have a diameter of, for example, 3 inches (approximately 7.62 mm).
Approximately 800 of them are formed on the surface of the wafer of CI).

When the wafer 4 thus prepared is placed in the plating solution 3 of the plating bath 1 and plated as shown in FIG. 5, a conductive film is attached to the coil pattern 4b to form a coil.

[Problem to be solved by the invention]

The electrical resistance of the coil formed by such conventional plating method 7 should not be too large in view of the generation of heat generation and thermal noise. In order to reduce the electrical resistance of the coil, it is possible to increase the thickness of the conductive film formed by plating, but since the insulating layer and magnetic film are then attached to the coil, it must be kept uniform and not too thick. There is a need.

In order to control the conductive film thickness in this way, since the conductive film thickness increases almost in proportion to the plating time, the conductive film thickness can be controlled to a certain extent by controlling the plating time.

However, unless various conditions such as the concentration and temperature of the plating solution are accurately controlled, there is a problem in that the conductive film thickness will vary.

The purpose of this invention is to measure the electrical resistance of the plating film thickness of the measurement plating part during the plating process, thereby indirectly measuring the plating film thickness of the plated member in real time and controlling the film thickness. That is.

[Means for Solving the Problems] In order to solve the above-mentioned problems, the present invention, as shown in FIGS. A plated part 4e for measuring the thickness of the plating film is provided integrally with or separately from the member (wafer 4 in the example), and the electrical resistance of the plating film coated on this plating part 4e for measurement is measured during the plating process. Accordingly, this method is characterized in that the thickness of the plating film plated on the member to be plated is controlled while indirectly measuring the thickness of the plating film plated on the member to be plated.

[Effect]

According to this invention, by measuring the electrical resistance of the plating film coated on the plating part 4e for measuring the plating film thickness during the plating process, the plating film thickness of the member to be plated can be indirectly measured in real time. Plating film thickness can be controlled.

[Embodiment 1 ('IIE) Hereinafter, an embodiment of the method for controlling the plating film thickness of the present invention will be described.

The principle of forming the coil of the thin film magnetic head by the plating method is the same as that described above with reference to FIGS. 5 and 6.

In the plating process of depositing a conductive material in the form of a film, this invention provides a plating part for measuring the coating film thickness, either integrally or separately from the member to be plated, and the plating film adhered to the coating part for measurement. Control of plating film thickness, characterized in that the thickness of the plating film coated on the member to be plated is controlled while indirectly measuring the electrical resistance of the plated film during the plating process. is a method,
This will be explained in detail with reference to the embodiments shown in FIGS. 1 to 4, with the same parts as those of the conventional example being given the same reference numerals.

That is, it is the same as the conventional example in that a photoresist 4c is attached on a seed layer 4a of a wafer 4, which is a member to be polished, leaving the coil pattern 4b and the plating current introduction part 4d.

In this invention, the seed layer 4a of the wafer 4
A coating part 4e for measuring the plating film thickness is further provided on the top,
As shown in FIG. 3, this wafer 4 is placed in the plating solution 3 of the coating tank 1 and plated. At that time, the electrical resistance is measured at the terminals 4el and 4ez of the plating part 4e for measuring the plating film thickness. Connect device 7.

In this way, as shown by curve A in Figure 4, the electrical resistance decreases as the plating film thickness increases, so by measuring this electrical resistance, the plating film thickness can be indirectly measured. can do. In this case,
Terminals 4el and 4ez of the plating part 4e for measuring the plating film thickness
is shorted in the seed layer 4a, so the terminal 4e
The electrical resistance between 4ez and 4ez is relatively small. Therefore, terminal 4
In order to increase the electrical resistance between el and dez and increase the measurement sensitivity, the terminal 4e is connected to the lead-in part 4d of the current.
If the periphery of the pattern from the terminal 4e to the terminal 4e2 is separated from the node layer 4a in advance, the terminal 4el and
The measurement sensitivity can be increased by increasing the electrical resistance between 4e2.

As shown in FIG. 1, the reason why the plating portions 4e for measuring the plating film thickness are provided at two locations is to measure the plating film thickness more accurately by averaging the measurement results at the two locations.

Further, in this embodiment, the plating part 4e for measuring the plating film thickness is provided integrally with the wafer 4, which is the member to be plated. Even if the plating part for thickness measurement is provided separately, the plating film thickness can be measured indirectly in the same way as in the case of Habo.

In addition, in this example, a method for controlling the plating film thickness when forming a coil of a thin film magnetic head by a plating method was explained, but the method is not limited to this and can be applied to any method for controlling the plating film thickness. can do.

[Effects of the Invention] As explained above, in the plating process of depositing a conductive material in the form of a film, the present invention provides a coating part for measuring the plating film thickness, either integrally with or separately from the member to be plated, and performing this measurement. By measuring the electrical resistance of the coating film applied to the plating part during the plating process, the plating film thickness can be controlled while indirectly measuring the plating film thickness on the plated part. Since the method for controlling the plating film thickness is characterized by The advantage is that the plating film thickness can be accurately controlled while measuring the plating film thickness in real time.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a photoresist pattern on the surface of a member to be plated in the method for controlling plating film thickness of the present invention;
Fig. 2 is an enlarged view of the plating part for measuring the plating film thickness, Fig. 3 is a diagram showing the plating apparatus in the method of controlling the plating film thickness of the present invention, and Fig. 4 is an enlarged view of the plating part for measuring the plating film thickness. Figure 5 is a diagram showing the change in electrical resistance with respect to film thickness. Figure 5 is a diagram showing a conventional general plating equipment. Figure 6 (A) is a diagram showing a photoresist used when forming a coil on a wafer using conventional plating technology. It is a front view showing a pattern, and (B) is a left side view. 1... Plating bath 2... Anode electrode 3... Plating solution 4... Wafer 4a which is a member to be plated... Seed layer 4b... Coil pattern 4C... Photoresist 4d... Plating current introduction part 4e...Plating part 4e, 4e for measuring plating film thickness
z-terminal 5...power supply 6...ammeter 7...electrical resistance measuring device

Claims (1)

[Claims] In the plating process in which a conductive material is deposited in the form of a film, a plating part (4e) for measuring the plating film thickness is provided integrally with or separately from the member to be plated, and the plating part (4e) is deposited on the plating part (4e) for measuring the thickness of the plating film. A plating film thickness that is characterized by controlling the plating film thickness while indirectly measuring the plating film thickness on a plated member by measuring the electrical resistance of the plating film during the plating process. control method.