JPS6282305A - Monitor pattern for measurint thickness of plating film - Google Patents

Abstract

PURPOSE:To easily perform inspection according to whether there is continuity between monitors or not by providing the 1st monitor couple whose center distance between starts of plating growth is twice as large as the permissible maximum value of plating film thickness and the 2nd monitor couple whose distance between starts of plating growth is twice as large as the permissible minimum value of the plating film thickness. CONSTITUTION:Photoresist 7 is applied over a semiconductor substrate 1, the 1st and the 2nd monitoir couples 2 and 3, a gold projection electrode 4, etc., and patterned, and nearly square holes 8, 9, and 10 are bored in the monitor couples 2 and 3 and electrode 4. The hole 8 is square and the intersection of its diagonals is a start point 11 of plating growth; and the intersection of the diagonals of the hole 9 is a start point 12 of plating growth as well. The interval between start points 11 is twice as large as the permissible maximum value of the thickness of the plating film and the interval between start points 12 is twice as larga as the permissible minimum value of the thickness of the plating film. Then, the substrate 1 is dipped in a gold plating liquid and electric power is supplied between the substrate 1 and an anode electrode plate to perform a plating process. Consequently, when the plating film is grown and the processing is finished, a gold projection nearly in an umbrella shape is formed. Consequently, when a measurement is taken, a specific voltage is impressed between the electrodes 4 and the voltage between the electrodes 4 is measured to decide whether the film thickness is within a permissible range or not.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a monitor pattern for measuring coating film thickness, in particular, a method of growing a metal wiring of a semiconductor device or a metal protrusion electrode with a trowel.
The present invention relates to a coating thickness measurement monitor pattern for measuring the coating thickness during formation.

(Prior art) Metal wiring or metal protruding electrodes that are generally formed with folds in semiconductor devices must be kept within a certain allowable film thickness range, and if the film thickness cannot be kept within a certain range, pinholes may occur. , short circuits between wires, etc. occur, resulting in serious failures in the functionality of the semiconductor device.

Therefore, we are trying to improve the reliability of semiconductor devices by measuring the film thickness of metal protruding electrodes, etc. To measure the film thickness, we use a surface grof filer to mechanically measure the physical level difference of metal protruding electrodes, etc. Measure and make allowances for its film thickness.

(Problems to be solved by the invention) However, in the conventional film thickness measurement method, physical steps such as metal protrusion electrodes were mechanically measured, which required many steps and a long process. There are problems in that it takes time and the surface of the metal protruding electrodes etc. is easily damaged due to mechanical contact.

(Means for Solving the Problems) In view of the above-mentioned problems of the prior art, the present invention provides a method in which, when growing a conductor film, the distance between each film growth start point is twice the maximum allowable value of the conductor Nd. The gist is that at least one pair of monitors and a second pair of monitors in which the distance between the starting points of each plate growth is twice the minimum allowable value of the conductive plate are provided.

(Function) On the first pair of monitors and the second pair of monitors, the conductor WMI starts to grow isotropically from the starting point of the ridge growth when the conductor ridge grows, and the protective film thickness reaches the minimum allowable value. When the protective film thickness exceeds the maximum allowable value, the second monitor pair connects, and when the protective film thickness exceeds the maximum allowable value, the first monitor pair connects. As a result, 1. When no current flows between the second pair of monitors, and when no current flows between the second pair of monitors, and the first pair of monitors. When a current flows between the second pair of monitors, the protective film thickness is not within the allowable range, and no current flows between the first pair of monitors.
Only when current flows through the second pair of monitors can it be known that the coating thickness is within an acceptable range.

(Example) FIGS. 1 to 8 are diagrams showing an example of the present invention,
Reference numeral 1 in the figure shows a semiconductor substrate on which a resistor has already been formed. On the substrate 1, a first pair of platinum monitors 2 and a second pair of platinum monitors 3 are patterned together with all protruding electrodes 4. It is formed. The first monitor pair 2 and the second monitor pair 3 are connected by a resistor 5, and the first monitor pair 2 and the entire protrusion polarization 4
It is connected with aluminum wiring 6.

Next, to explain the manufacturing process of one embodiment, after a metal thin film is deposited on the semiconductor substrate 1, an etching method or an etching method is used.
The first method using the Tooff method. A second monitor pair 2.3 and all protruding electrodes 4 are formed, and a resistor 5 is obtained by introducing impurities into polysilicon using a phosphorography process and a diffusion process. Further, the aluminum wiring 6 is also obtained by depositing an aluminum film and then forming a pattern using a phosphorography process.

After obtaining the groove structure shown in FIGS. 1 and 2 in this manner, the semiconductor substrate 1. 1st. A photoresist 7 is applied on the second monitor pair 2.3 and all the protruding electrodes 4, etc., and is patterned to form approximately square holes 8.9.10 on the first. 12th
Drills are made on the monitor pair 2, 3 and the electrode 4, respectively (FIGS. 3 and 4). Since the hole 8 is a square with one side parallel to each other, the intersection of each diagonal line is the sill growth starting point 11, and similarly for the hole 9, the intersection of each diagonal line is the sill growth starting point 12. The interval between the ridge growth starting points 11 is twice the maximum allowable thickness of the protective film, and the interval between the ridge growth starting points 12 is twice the allowable minimum thickness of the protective film.

Thereafter, the semiconductor substrate 1 is immersed in gold plating, and electricity is applied between the substrate 1 and the anode electrode plate to perform the plating process. As a result, a broken membrane grows from within the holes 8 to 10, and when the protective membrane exceeds the film thickness of the photoresist 7, the protective membrane grows isotropically around the ridge growth starting point 11, 12. The plating process for the specified time is completed.
L. When the photoresist 7 is removed, the first.L. On the second monitor pair 2, 3 and 'ICIC, there is a roughly umbrella-shaped gold arrow 12.
, 13, and 14 are formed respectively (Fig. 5, 6).
figure).

Next, a method for measuring the thickness of the broken gold film grown in the process will be explained. During the measurement, a predetermined voltage is applied between all the protruding electrodes 4. First, if the film thickness is within the allowable range, all the protrusions 13 on the second monitor pair 2 are connected to each other as shown in FIGS. In between, the voltage drop across the resistor 5 is measured. On the other hand, if the film thickness is less than the minimum allowable value, none of the protrusions 12, 13 are connected, and therefore no current flows between the electrodes 4.

On the other hand, if the film thickness exceeds the maximum allowable value, all the protrusions 13 are also connected, so the first monitor pair 2 is short-circuited and the voltage drop between the electrodes 4 is reduced. Therefore, by measuring the voltage between the electrodes 4, it is possible to determine whether the film thickness is within the allowable range.

In addition, in the above embodiment, the first monitor pair 2 is connected to the full-projection electrode 4, and the electrode 4 is also used as an electrode for film thickness determination, so that the protective film is automatically detected during the calibration process of the semiconductor device. Thickness is also determined, and the number of inspection steps can be reduced.

Furthermore, if three or more pairs of monitors are provided and the distance between the ridge growth starting points is varied in multiple stages, precise film thickness measurements can be performed.

(Effects) As explained above, in the present invention, the first pair of monitors in which the distance between the centers of ridge growth initiation is twice the maximum allowable value of the protective film thickness;
Since there is at least a second pair of monitors in which the distance between the starting points of the ridge growth is twice the minimum allowable value of the protective film thickness, the film thickness can be inspected by checking the presence or absence of conduction between each pair of monitors. This has the effect that the film thickness can be easily inspected without damaging the conductor protective film.

[Brief explanation of drawings]

Fig. 1 is a plan view showing an embodiment of the invention, Fig. 2 fa)
1. FIG. 3 is a plan view showing an intermediate step in one embodiment. FIG. 4(a)
3. FIG. 5 is a plan view showing an example when the film thickness is within the allowable range. Figures (a) to (C) are cross-sectional views taken at the same positions as Figures 2 (a) to (C) in Figure 5, and Figure 7 shows an example in which the film thickness exceeds the maximum allowable value. The plan view and FIGS. 8(a) to fe) are cross-sectional views taken at the same positions as FIGS. 2(a) to (C) in FIG. 7. 1...-board, 2...-first monitor pair, 3
. . . 2nd monitor pair, 11. 12 . . . ridge growth starting point, 14 . Agent Patent Attorney Susumu Uchihara ゛Includes 15 1 drawing plan 2 drawing plot 3 plots plot 4 plot rough S plot plot 7th plot plot 8 plots

Claims (1)

[Claims] A monitor pattern for measuring the thickness of a conductive coating grown isotropically on a substrate, the monitor pattern having a distance between each coating growth starting point that is at least twice the maximum allowable value of the conductive coating. a first pair of monitors and a second pair of monitors in which the spacing between the starting points of each coating is twice the minimum allowable value for the conductive coating; is a monitor pattern for measuring the thickness of the conductive film that can be grown during the growth of the conductive film.