JPS5938725B2 - Method of manufacturing thin film capacitors - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for depositing Ta2NO, Ta, etc. on an insulating substrate such as glass.
The present invention relates to a method for manufacturing a thin film capacitor having a dielectric thin film such as No. 205.

When manufacturing a thin film capacitor, it is difficult to obtain a desired capacitance without adjusting the capacitance value.

For this reason, conventionally, Ta2N or Ta was placed on a glass substrate.
A lower electrode such as TaNO51J or Ta2o is provided in a state where the lower electrode is divided into a first part and a second part, and this lower electrode is anodized. An upper electrode for the main capacitance is provided on the dielectric thin film of the second portion, and a plurality of upper electrodes for capacitance adjustment are provided on the dielectric thin film of the second portion.At this stage, the lower electrode and the upper electrode for the main capacitance are Connect a meter to measure the capacitance, and if the desired capacitance value is not obtained, use a laser beam to selectively cut between the main capacitance upper electrode and multiple capacitance adjustment upper electrodes. The desired capacitance value was determined from this value.

However, since the protective insulating layer is provided, the melt amount is measured, and the laser beam is projected, there is a possibility that the characteristics of the capacitor may deteriorate or be damaged during this step.

Furthermore, even if the capacitance is adjusted, if a protective insulating layer is subsequently provided or soldered to the circuit board, the capacitance will change due to thermal effects, mechanical effects such as stress, etc., and the desired capacitance value will not be achieved. It was sometimes difficult to obtain.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a method for manufacturing a thin film capacitor that can easily obtain a certain capacitance value.

To achieve the above object, the present invention comprises a step of forming a lower electrode on a light-transmissive insulating substrate, comprising at least a first portion and a second portion continuous with the first portion; forming a dielectric thin film on a portion of the first portion and the second portion by treatment; and providing an upper electrode for main capacitance on the dielectric thin film on the first portion; A plurality of capacitance adjustment upper electrodes are provided on the dielectric thin film on the second portion, and the main capacitance adjustment upper electrode and the plurality of capacitance adjustment upper electrodes are electrically connected to each other. a step of providing a plurality of connection parts on the insulating substrate, the main capacitance upper electrode, the plurality of capacitance adjustment upper electrodes, the plurality of connection parts, the exposed surface of the dielectric thin film, and at least the connection. a step of providing a protective insulating layer so as to cover the insulating substrate near the section; and after providing the protective insulating layer, connecting the lower electrode and the upper electrode for main capacitance with a capacitance measuring instrument; measuring the capacitance; and projecting one or more laser beams from the back surface of the insulating substrate opposite to the surface on which the lower electrode is provided to connect the connecting portions. This relates to a method for manufacturing a thin film capacitor, which comprises the steps of cutting and adjusting the capacitance value to a predetermined value.

According to the above invention, since the capacitance is adjusted by projecting a laser beam from the back surface of the glass substrate after forming the protective insulating layer, it is also possible to correct the change in capacitance due to the formation of the protective insulating layer.

Further, since capacitance measurement and laser beam projection are performed after forming the protective insulating layer, deterioration or damage to characteristics in this process can be prevented.

Next, a method for manufacturing a thin film capacitor according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

1A to 1E are plan views showing the first thin film capacitor in the process order, and FIGS. 2A to 2E are sectional views of various parts of FIG. 1.

First, the upper part of the transparent glass substrate 1 of about 0.5 mm is made of Ta2.
By forming an N film to a thickness of approximately 6,000 yen by sputtering or vapor deposition, and photoetching this into a predetermined pattern, as shown in A1 of FIGS. 1 and 2,
Lower electrode 2 consisting of a first part 2a and a second part 2b
form.

Note that the second portion 2b is connected to the first portion 2al and is placed opposite to the first portion 2al with the separation region 3 interposed therebetween.

Next, by partially anodizing the lower electrode 2, a dielectric thin film 4 of about 3,000 layers made of TaNx0Y is formed, as shown in FIGS.

Next, NiCr is sputtered or vapor-deposited to a thickness of 500 mm and Au to a thickness of 1000 mm, and this is etched into a desired pattern.Thus, as shown in C of FIGS. 1 and 2, the lower electrode 2 is formed. the first part of 2
A corresponding upper electrode 5 for main capacitance, a plurality of upper electrodes 6 for capacitance adjustment corresponding to the second portion 2b of the lower electrode 2
, a connecting portion 7 for connecting the main capacitance upper electrode 5 and the adjustment upper electrode 6 is provided.

At this time, a lower electrode terminal portion 8 and an upper electrode terminal portion 9 are provided from the same metal.

As is clear from FIG. 1C, one or more capacitance adjusting upper electrodes 6 and connecting portions 7 are provided in a state in which they protrude from the main capacitance upper electrode 5 in a comb-like shape.

Next, place one layer to cover the main capacitance upper electrode 5, the plurality of capacitance adjustment upper electrodes 6, the plurality of connection parts 7, the exposed surface of the dielectric thin film 4, and at least the glass substrate 1 in the vicinity of the connection parts 7. The protective insulating layer 10 made of epoxy resin is shown in FIGS.
1) Provide as shown in the figure.

The insulating layer 10 is formed to have a thickness of about 12 μm by applying an epoxy resin and heating it in air at 150° C.

Next, a capacitance measuring instrument (not shown) is connected to the lower electrode 2 and the upper electrode 5 for main capacitance via the terminal parts 8 and 9,
Perform capacitance measurement.

As a result, the sum of the capacitance between the first portion 2a of the lower electrode 2 and the main capacitance upper electrode 5 and the capacitance between the second portion 2b of the lower electrode 2 and the capacitance adjustment upper electrode 6 is be measured.

Next, since this embodiment is designed to obtain a larger amount of melt than the desired capacity, some of the plurality of connecting portions 7 are shown in the partially cutaway plan view of FIG. As shown in the cross-sectional view of Figure E, the structure is analyzed using a laser beam, and the capacitance value is adjusted once to the desired value.

At this time, by utilizing the fact that the glass substrate 1 is transparent, the second
As shown by an arrow 11 in the diagram, an Nd:YAG laser beam is projected onto the connection portion Tf from the back side of the glass substrate 1, and the connection portion 7 is cut by the energy of the laser beam.

Next, on a circuit board (not shown) on which one wiring conductor has been previously soldered, place the elements shown in the face-down bonding format (FIGS. 1 and 2), and place the elements shown in FIGS.
The terminal portions 8, 9 are connected to the circuit board by a solder reflow method at 70°C.

This makes it possible to see the connection part 7 from the glass substrate 1 side, so after mounting the circuit board element, measure the capacitance and set the laser beam to the desired capacitance. It is possible to adjust the capacitance by analyzing the connection part 7 with the beam.

As is clear from the above, this embodiment has the following advantages.

(a) When the protective insulating layer 10 is formed, the capacitance value is 0.5
The capacitance increases by ~2.5%, but since the capacitance is adjusted once after forming the protective insulating layer 10, it is possible to adjust the capacitance so as to eliminate changes and variations in capacitance due to the formation of the protective insulating layer 10. .

(b) After providing the protective insulating layer 10, measurement and capacitance adjustment using the laser beam I are performed, so that deterioration of characteristics and damage during these steps can be prevented.

(C) Since the capacitance can be adjusted even more after face-down bonding, it is also possible to correct capacitance changes caused by heat during solder bonding.

Although the embodiments of the present invention have been described above, the present invention is limited to the first embodiment and can be further modified.

For example, the lower electrode 2 is made of Ta, and the dielectric thin film 4 is made of Ta205.
etc.

Further, the insulating layer 10 may be formed of SiO2, silicone resin, or the like.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing the thin film capacitor according to the first embodiment of the present invention in the order of steps;
They are cross-sectional views a, b, c, d, and e in the figure. In the reference numeral 1 used in the drawings, 1 is a glass substrate, 2 is a lower electrode, 2a is a first part, 2b is a second part, 4 is a dielectric thin film, and 5 is an upper electrode for main capacitance. , 6 is an upper electrode for capacitance adjustment, 7 is a connecting portion, and 10 is a protective insulating layer.

Claims (1)

[Claims] 1. A step of forming a lower electrode on a light-transmissive insulating substrate, comprising at least a first portion and a second portion continuous with the first portion; and oxidation treatment. forming a dielectric thin film on a portion of the first portion and the second portion; providing an upper electrode for main capacitance on the dielectric thin film on the first portion; A plurality of capacitance adjustment upper electrodes are provided on the dielectric thin film on the portion, and one or more connections are provided to electrically connect the main capacitance adjustment upper electrode and the plurality of capacitance adjustment upper electrodes, respectively. a step of providing a part on the insulating substrate 1, the upper electrode for main capacitance, the upper electrode for adjusting capacitance of corrosion, the plurality of connection parts, the exposed surface of the dielectric thin film,
and a step of providing a protective insulating layer so as to cover at least the insulating substrate in the vicinity of the connection portion, and after providing the protective insulating layer, connecting a capacitance measuring instrument to the lower electrode and the upper electrode for main capacitance. projecting a laser beam onto one or more of the plurality of connection portions from the back side of the insulating substrate opposite to the surface on which the lower electrode is provided; A method for manufacturing a thin film capacitor, comprising the steps of: cutting the connecting portion; and adjusting the capacitance value to a desired value.