JPS6248886B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a method for manufacturing a laminated transformer.

A conventional transformer consists of a magnetic core having an E-I shape, an E-shape, an E-Y shape, etc., and an insulated conductor wire wound around any leg of the core to form a pair of coils. However, the transformer using this method requires a complicated winding process, and the manufactured transformer becomes large.

The present inventors proposed a method of manufacturing a transformer using a lamination method in Japanese Patent Application No. 127899/1989 in order to solve the problems of the conventional transformer using a winding method. The method of the same application prepares a paste containing magnetic powder and a paste containing conductive powder, and applies printing technology to print and laminate them in an appropriate order.
The overall arrangement is to provide two equivalent coils and a magnetically permeable core for the magnetic path passing through these coils. The printed laminate is sintered at high temperature in a firing furnace. Therefore, an expensive heat-resistant metal material such as Pd or Ag-Pd is required as the conductive powder, and high-temperature treatment is also required.
Furthermore, the stacked layers cannot be made very thin, so the reduction in size is still insufficient, and it is difficult to achieve large mutual and self-induction coefficients. Furthermore, accuracy may not be sufficiently controlled in some cases.

The present invention aims to further improve the manufacturing technology of laminated transformers, and provides a method for manufacturing laminated transformers using a film forming technique using sputtering instead of printing. Since the method of the present invention does not require a firing process, it not only allows the use of any conductive material such as Cu, Al, Ag, etc., but also enables the creation of a laminated transformer with uniform and thin thickness for each layer and with good precision. Can be provided.

The invention is implemented using a sputtering method. Forming two or more coils of a transformer requires metal for forming a coiled or spiral conductive pattern and a magnetic material for insulating the conductive pattern. According to the sputtering method, MO・
Formation of magnetic layers such as oxide ferrite represented by Fe ₂ O ₃ (M: metal) and
Conductive metal layers such as Al, Cu, and Ag can be formed without difficulty. Therefore, a firing process is not necessary, and the object of the present invention can be sufficiently achieved using inexpensive metals.

The major feature of the multilayer transformer obtained by the method of the present invention is that the thickness of each layer can be close to the angstrom unit (10 ^-1 〓m).
The advantage is that even relatively thin stacks can have large mutual inductances, and that laminated transformers with a very wide range of mutual inductance values can therefore be produced at will.

Although the sputtering method has a somewhat slower film formation rate than other methods, high-speed sputtering methods have recently been developed. The sputtering method has the characteristic that the composition of the insulator source or metal source can be transferred almost directly to the composition of the produced film, and furthermore, the adhesion strength is high and the produced film is uniform, so it is a particularly preferred method. Note that the sputtering method increases the wrap-around phenomenon, so the mask is placed as close to the surface of the substrate as possible.

Embodiments of the invention will now be described in detail with reference to the drawings.

Figure 1 is a diagram showing the principle of the sputtering method, in which a negative electrode A and a ground electrode B are placed facing each other in a vacuum chamber sealed with argon gas of about 10 ^-3 to ^{10 -2} Torr, and a high-frequency voltage ( ~10MHz, etc.). A plate C of metal or oxide to be vapor-deposited is held on the surface of the negative electrode A, a substrate D for vapor deposition is positioned on the surface of the ground electrode B, and a mask E is placed on the surface of the substrate D. When a high frequency voltage is applied between electrodes A and B, the metal or oxide plate C is bombarded with positively ionized gas, and atoms or molecules of the metal or oxide are ejected from the surface of the plate C at a large speed. It is sputtered toward the substrate D to form a thin film. Incidentally, since the sputtering method is well known, there is no need for further detailed explanation.

2 to 7 are process diagrams showing a first embodiment of the method for manufacturing a laminated transformer according to the present invention, and FIG. 8 is an equivalent circuit diagram of the same laminated transformer. First, the second
As shown, an insulating ferrite magnetic film 1 is sputtered onto a substrate (D in FIG. 1) through a suitable mask (not shown). The substrate is, for example, a metal plate with a removable surface, or a plate with an appropriate thickness and the same size as the magnetic film 1, and these substrates can be peeled off later, or can be used as an integral part of the laminate. It may be a part of it. Furthermore, a large number of identical-shaped through holes or patterns may be formed on the mask to manufacture a large number of laminated transformers at the same time. In the following, when referring to a magnetic film, we refer to the same ferrite magnetic material, and when referring to a conductor, we refer to the same conductor (Al, Cu, Ag, etc.).

Returning to the explanation of FIG. 2, after the formation of the magnetic film 1 is completed, symmetrical hook-shaped conductors 2 and 3 are formed on the surface of the magnetic film 1 by sputtering through a mask (not shown). Reference numerals 4 and 5 are lead-out portions of the single bodies 2 and 3 exposed at the lower side of the magnetic film 1, and 6 and 7 are inner ends of the conductors 2 and 3. Next, as shown in FIG. 3, magnetic materials 8 and 9 are formed by sputtering on the other portions of the conductors 2 and 3, except for the inner ends 6 and 7. Next, as shown in FIG. 4, the substantially circular conductors 10, 11 are overlapped with the inner ends 6, 7 of the lower conductors 2, 3, and the outer ends are exposed to the upper side of the laminate. 13. In this way two closely spaced coils of one turn each are formed. Although the above-mentioned coil consists of only one turn, the number of laminated magnetic films and conductors may be increased to obtain the required number of turns, if necessary. Finally, as shown in FIG. 5, a magnetic film 16 is formed on the entire surface to complete the lamination process. After taking out the laminate from the vacuum chamber, a suitable conductive paste (conductive paste containing metal powder) is baked into the corners of the four sides of the laminate as shown in FIGS. 6 and 7 to form external terminals 17, 18, 1
9,20. The external terminals are located in contact with the lead-out portions 4, 5, 12, and 13 of the conductors.

FIG. 7 shows the completed laminated transformer, and FIG. 8 is its equivalent circuit diagram.

The above example was a parallel type transformer, but the method for manufacturing a laminated transformer with a high degree of coupling is described in Section 9-18.
As shown in the figure. This example also uses the sputtering method. Referring to FIG. 9, first, the magnetic film 2
1 is formed, and then an L-shaped conductor 22 is formed.
The outer end 23 of the conductor 22 is exposed at the lower side of the magnetic film 21, and the inner end 24 remains inside the magnetic film 21. Next, as shown in FIG. 10, a magnetic material 25 is formed on the left part of the magnetic film 21, leaving the inner end 24 of the conductor 22, and then the outer end 27 is exposed on the upper side of the laminate as shown in FIG. Furthermore, a conductor 26 is formed whose inner end 28 terminates on the magnetic film 25 . As shown in FIG. 12, a wide L-shaped magnetic film 29 is formed leaving the ends 24 and 28 of the conductors 22 and 26, and then a conductor extending from the end 28 of the conductor 26 is formed as shown in FIG. 30
form. As shown in FIG. 14, a magnetic film 33 is formed leaving the end 32 of the conductor 30, and then the 15th
As shown, a generally U-shaped conductor 34 is formed extending from the distal end 24 of the conductor 22, with its outer end 36 exposed at the top side of the laminate. Moving on to the process shown in FIG. 16, a magnetic film 37 is formed on the entire surface leaving the end of the conductor 30, and then as shown in FIG.
An outer end 40 extending from 2 and terminating at the bottom edge of the laminate.
A conductor 38 is formed. When the lamination is completed as described above, take out the laminated body from the vacuum chamber and
External terminals 42, 44, 43, 4 connected to the outer ends 23, 27, 36, 40 of the conductor, respectively, as shown in the figure.
Burn 5. In the laminated transformer shown in FIG. 18, the magnetic path of each coil is almost the same as the magnetic path of the other coil.

19 to 29 show an example in which the method of the present invention is applied to a rotary transformer. An example of a rotary transformer, as shown in FIG.
The rotor R held at 6 is placed close to the rotor R, and the coupling of the coils is changed by the rotation of the rotor R. According to the invention, rotor R is manufactured as follows.

As shown in FIG. 19, the magnetic film 51 is first formed in a disk shape, and then the magnetic film 51 is formed with S ₁ as the starting point.
A conductor 52 having a small circular arc exposed at the lower side and terminating at the end 50 is formed. As shown in FIG. 20, a magnetic film 54 is formed over the entire surface of a magnetic film 51 having holes 53 that expose the ends 50 of the conductors 52. As shown in FIG. Next, as shown in FIG.
A conductor 55 forming a small arc connected to S 2 and a conductor 56 forming a large arc starting from S ₂ and terminating at 58 are formed, and the ends 57 and 58 are formed as shown in FIG.
A magnetic film 61 having holes 59 and 60 exposing the magnetic material is formed over the entire surface. 23, small arc and large arc conductors 62, 63 connected to the ends 57, 58 of the lower conductor are formed, and the ends 62, 63 of the conductors 62, 63 are formed thereon as shown in FIG. , 65 is formed, and as shown in FIG. The end of is exposed at the bottom side of the laminate to form the terminal end _F1 . Conductor 70 as shown in FIG.
A magnetic film 7 having a hole 72 exposing an end 71 of the magnetic film 7
3 on the entire surface, then conductor 7 as shown in Fig. 27.
4 is formed so as to be connected to the end 71 of the lower conductor 70, and its outer end is exposed around the laminate and terminated.
Let it be F ₂ . Next, as shown in FIG. 28, a magnetic film 75 is formed on the entire surface, and finally the terminal ends S ₁ , S ₂ , F ₁ , F ₂
External terminals 77, 78, 79, and 80 to be connected to are formed by baking conductive paste. Since the rotor R of the laminated transformer is formed as described above, it can be used together with the stator S by adhering the rotating shaft 76 to the rotor R. The equivalent circuit of FIG. 29 is as shown in FIG. 30.

The method for manufacturing a laminated transformer using the sputtering method has been described above for three embodiments.

As described above, since the present invention utilizes a thin film forming technique using a sputtering method, a laminated transformer can be manufactured with high precision through a consistent process. Since each layer of the laminate is extremely thin, the dimensions of the product can be made small, and the number of conductor turns can be adjusted arbitrarily, making it possible to provide an extremely wide range of inductance values with a small laminate transformer. Moreover, since the laminated transformer obtained by the present invention is in the form of a chip having external terminals, it is convenient for direct attachment to a printed circuit board or soldering. Furthermore, since no firing is required, inexpensive metals can be used as conductors.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an example of an apparatus for carrying out the method of the present invention, and FIGS.
FIG. 7 is a perspective view of a completed multilayer transformer, FIG. 8 is an equivalent circuit diagram, and FIGS. 9 to 18 are plan views showing the sequential steps of the second embodiment of the present invention. Plan views shown in Figures 19 to 28
29 is a side view of a completed rotor combined with a stator, and FIG. 30 is an equivalent circuit diagram of FIG. 29. In the figure, the main members are as follows. 1, 8, 9, 16: magnetic film, 2, 3, 10,
11: Conductor, 17, 18, 19, 20: External terminal, 21, 25, 29, 33, 37, 41: Magnetic film, 22, 26, 30, 34, 38: Conductor, 4
2, 43, 44, 45: external terminal, 51, 54,
61, 66, 73, 75: magnetic film, 52, 5
6, 62, 63, 69, 70, 74: Conductor, 7
7, 78, 79, 80: External terminals.

Claims (1)

[Claims] 1. An insulating oxide magnetic layer and at least two sets of metal conductors are alternately laminated on a substrate by a sputtering method, and at that time, the conductors of each set are continuously stacked from between the magnetic layers. 1. A method of manufacturing a laminated transformer, comprising forming a single coil-shaped conductive path that circulates around the conductor, and then providing an external terminal connected to an end of the conductor on the outer surface of the laminated body.