JPS596372A - Method and apparatus for partial vacuum vapor deposition of metal strip - Google Patents

Abstract

PURPOSE:To form a partial vacuum vapor deposition film on a metal strip in good efficiency, by a method wherein a metal strip and a strip shaped mask are run in a closely contacted state in a vacuum container to deposit a substance to be vapor deposited and subsequenty wound up separately to enhance positioning preciseness. CONSTITUTION:A metal strip 32 and a strip shaped mask 48 are mounted to delivery reels 30, 46 in a vacuum container 20. Reels 34, 50 are rotated to run the metal strip 32 and the strip shaped mask 48 in synchronous relationship and th metal strip 32 is heated by a preheater 60. After the positional alignment of the metal strip 32 and the mask 48 is carried out by sprockets 38, 56, both of which are superimposed between press rollers 40 to be passed through a cover 26 from a slit 28 and a metal such as Al evaporated from an evaporation tray 22 is continuously deposited on the metal strip 32 through the opening of the mask 48. The metal strip 32 and the mask 48 passing the cover 26 are separated through press rollers 42 and respectively wound up by the reels 34, 50.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a partial vacuum evaporation method for a metal strip, which allows metal coatings of a desired shape to be deposited on the metal strip at predetermined intervals in the longitudinal direction and direction with high positioning accuracy and efficiency. and regarding its equipment.

Nowadays, lead frames used for electronic components, etc., are coated with aluminum or aluminum alloy instead of gold plating, silver plating, etc. on predetermined positions such as bonding areas. There is a need for an efficient manufacturing method that is cost effective.

Electroplating is commonly used to form a metal film on a metal surface, but electroplating of aluminum has not yet reached the stage of industrialization.

Conventionally, in order to form such an aluminum film, a cladding method is generally adopted in which aluminum foil is crimped with appropriate rollers, etc., but it is difficult to partially form a film in a predetermined shape at regular intervals. In such cases, vacuum evaporation methods have been attempted.

In this vacuum deposition method, in order to obtain a metal strip partially coated with a vapor-deposited film as described in Section 2, it is necessary to first coat the entire surface of the metal strip with a vapor-deposited film, and then apply a vapor-deposited film. It is conceivable to attach the covering tape only to the necessary parts and remove the covering tape after removing the deposited film on unnecessary parts by chemical etching, etc., but it is also possible to apply small pieces of the covering tape to the necessary parts or peel it off. The work to do this is not easy and the workability is poor. In addition, considering the workability of peeling, a method of punching holes in a continuous covering tape and pasting it is considered, but in addition to being difficult to paste, accurate positioning cannot be performed because the covering tape expands and contracts. Furthermore, methods using these coated tapes have the disadvantage that the adhesive of the coated tape remains on the vapor-deposited film.

Furthermore, instead of using a covering tape, there is a method of applying a resist film to the necessary parts and corroding away the unnecessary parts, but this method requires a step of removing the resist film after treatment, which is not efficient.

Further, conventionally, as shown in FIG. 1(a) or (b), a lead frame 12.10 having a vapor deposited film region 10.10.
To manufacture 12', before applying the vapor deposition film, the metal strip is continuously pressed to form a lead frame strip, and then cut into a sheet shape in which multiple unit lead frames are connected. Alternatively, the IJ-1' frame formed by etching a metal sheet is mounted on an appropriate vapor deposition jig, covering the unnecessary parts with a metal mask, and the parts are etched using a vacuum process such as vacuum vapor deposition. A method of depositing a vapor-deposited film is also used.

However, in the above method, the work of attaching and removing the lead frame formed by pressing etc. to a vapor deposition jig equipped with a metal mask etc. requires manual labor, which not only results in poor workability but also The problem is that it is easy to cause deformation. Furthermore, since the metal strip cannot be continuously processed as it is, the amount of processing per time is limited, resulting in poor productivity and high costs.

The present invention was made to solve the above-mentioned difficulties in the vacuum vapor deposition method, and its purpose is to provide partial vacuum vapor deposition of metal strips that can continuously and efficiently form a vapor deposited film with good positioning accuracy. The method is characterized in that a metal strip and an opening having the shape of the vapor deposition film to be applied to the metal strip are provided in a vacuum container equipped with vapor deposition means including an evaporation pot. and a strip mask formed at regular intervals in the longitudinal direction are run in close contact at least in the evaporation region, and the material to be evaporated from the evaporation pot is passed through the opening and onto the metal strip. After being coated, the metal strip and the strip mask are wound up separately.

Another object of the present invention is to provide a partial vacuum deposition apparatus for metal strips, which is characterized by:
A vacuum container connected to an appropriate vacuum device, an evaporation pot that houses an evaporation source of aluminum or the like placed inside the vacuum container, a heating device that heats the evaporation source, and a heating device located on both sides of the evaporation pot. a metal strip unwinding means and a metal strip winding means respectively arranged in the evaporator, a strip mask unwinding means and a strip mask winding means respectively arranged on both sides of the evaporation pot, and the metal strip A metal strip fed out from the strip feeding means and wound up on a metal band winding means and a strip mask fed out from the strip mask feeding means and wound up on a strip mask winding means are arranged at least within a vapor deposition region. presser rollers located on both sides of the evaporation pot to bring them into close contact; and a constant-speed drive mechanism that runs the metal strip and the strip mask at a constant speed and synchronously at least within the evaporation region. It's because it's configured.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, the apparatus of the present invention will be explained.

In FIG. 2, reference numeral 20 is a vacuum container formed to have an appropriate pressure-resistant structure, and a vapor deposition device described below is housed inside the vacuum container.

Reference numeral 22 denotes an evaporation pot supported by appropriate members, into which aluminum, aluminum alloy, or the like as an evaporation source is charged. A heater 24 heats and melts the aluminum contained in the evaporating pot 22 to evaporate it. Note that the heating device is not limited to the above heater, and an electron beam may be used as a heating source.

Reference numeral 26 is an integrated cover that closes off the top and sides of the evaporation pot 22 to prevent aluminum evaporated from the evaporation pot 22 from scattering around.

Note that 28 is a slit provided on the side wall of the cover unit 26 for passing through the metal strip and the strip mask, and is located above the top surface of the evaporation pot 22.

30 is a feeding reel around which a metal strip 32 is wound;
Reference numeral 4 denotes a take-up reel for the metal strip 32, which are disposed on both sides of the cover unit 26 so as to be located above the slit 28.

As shown in FIG. 3, the metal strip 32 has reference holes 36 for positioning at predetermined intervals in the longitudinal direction on both sides in the width direction.
is transparent. Note that the metal strip 32 may be press-formed in advance into the shape of a lead frame as shown in FIG. 1.

After this metal strip 32 leaves the feeding reel 3o, it passes through a positioning sprocket 38 that meshes with the reference hole 36, passes through a pair of press rollers 4o, enters the cover unit 26 through the slit 28, and Passing above the evaporating pot 22 and penetrating the cover unit 26, a pair of presser rollers 42
, and is wound onto the take-up reel 34 via a pair of presser rollers 44.

46 is a feeding reel around which the metal strip mask 48 is wound; 50 is a take-up reel for the strip mask 48; It is located so that it is located at

As shown in FIG. 4, the strip mask 48 is provided with reference holes 52 for alignment on both sides in the width direction at the same pitch as the reference holes 36 made transparent in the metal strip 32, and furthermore, in the center part. Openings 54 having the shape of the desired vapor-deposited film are formed at predetermined intervals in the longitudinal direction.

After the strip mask 48 exits the feeding reel 46, it passes through a positioning sprocket 56 that meshes with the reference hole 52, is pinched between the pair of presser rollers 4o, and overlaps with the metal strip 32. It enters into the cover unit 26 through the slit 28, passes above the evaporation pot 22 facing the evaporation pot 22 side, penetrates the cover unit 26, and then passes through the pair of presser rollers 42 to form the metal strip 32. The film is separated and wound onto a winding reel 50 via a pair of presser rollers 58 .

The positioning sprocket 38 and the positioning sprocket 56 are formed to have exactly the same shape and size,
For example, by being connected and synchronized by a chain (not shown) or the like, the metal strip 32 and the strip mask 48 run in synchronization at the same speed, and at this time, the strip mask 4
The opening 54 provided in the metal strip 8 corresponds to a predetermined position where the vapor-deposited film of the metal strip 32 is to be formed.

A preheater 60 is provided between the alignment sprocket 38 and the presser roller 40, and is designed to heat the metal strip 32 to a required temperature before passing over the evaporating pot 22'.

In addition, it is preferable to arrange a preheating heater (not shown) also on the strip mask side for preheating, so that the metal strip does not come into contact with the strip mask and cool it.

Next, the operation of the above apparatus will be explained together with the method of the present invention.

First, the metal strip 32 and the strip mask 48 are respectively attached to the feeding reel 30.46, and the beginning ends of the metal strip 32 and the strip mask 48 are passed through each sprocket, each presser roller, etc. as described above, and then reeled onto the take-up reel. Wind it to 34°50.

Next, a vacuum device (not shown) is operated to reduce the pressure inside the vacuum container 20 to the required pressure (approximately 10 torr), and the preheater 60 is used to heat the metal strip 32 at an angle of approximately 50°.
The evaporating pot 22 is heated to
The aluminum put into the tank is melted and heated to a temperature that allows vapor deposition.

The appropriate drive motors (not shown) are then started to rotate each take-up reel 34.50, and the metal strip 32.50 is rotated. By running and winding the strip mask 48 in synchronization, aluminum vapor deposit can be continuously deposited on the metal strip 32 at desired positions through the openings 54 of the strip mask 48 ( (See Figure 5).

In order to make this aluminum coating a constant thickness, the vapor deposition pot 22
Metal strip 32 passing above. It is necessary to keep the running speed of the strip mask 48 constant. Alternatively, it is conceivable to increase or decrease the amount of evaporation by changing the evaporation conditions in accordance with the changing running speed, but there are some difficulties in setting the changing conditions.

In order to keep the traveling speed constant, the take-up reel 34
．． It is preferable to control a drive motor (not shown) using a variable speed motor as appropriate so that the rotational speed of 50 is decreased in accordance with an increase in the amount of winding.

Alternatively, the presser roller 4o or the presser roller 42 is connected to a drive motor (not shown) and rotated at a constant speed to continuously feed the metal strip 32 and the strip mask 48, and the take-up reel 34.50 It is also possible to wind it up while pulling it with a constant torque.

Note that the constant speed mechanism is not limited to the one described above, and it is of course possible to employ various other constant speed mechanisms.

In addition, each sprocket 38.5 is used as a positioning mechanism.
In addition to using the metal strip 32.6, other mechanical or optical positioning mechanisms may also be used, and the metal strip 32. A positioning mechanism is not necessarily required as long as the strip mask 48 can be fed completely synchronously.

FIG. 6 shows another embodiment.

This embodiment is the same as the above embodiment except that the strip mask 48 is formed endless and is fed at a constant speed in synchronization with the metal strip 32 by a sprocket 62. This embodiment also has the same effect as above, but the striped mask 4
8, because aluminum deposits gradually accumulate,
It is preferable to provide a scraping plate (not shown) as appropriate and scrape it off, or to replace the endless strip mask 48 as appropriate (reusable).

FIG. 7 shows yet another embodiment.

This embodiment is the same as the first embodiment except that the strip mask 48 is overlapped with the metal strip 32 and wound around one feeding reel 30.

In this embodiment, the metal strip 32 has the reference hole 36.
Alternatively, when the reference hole 36 and the IJ-F frame shape are press-molded in advance, the reference hole 52 and the opening 54 are press-formed on the strip mask 48 using another press device, or the reference hole 52 and the opening 54 are already press-formed. This is convenient for winding objects on one reel at the same time.

In yet another embodiment, the metal strip and the strip mask are wound on separate feeding reels, and these are attached to separate positions on the same axis, and then fed out and overlapped in front of the post-evaporation position. You may set it to match.

In any of the above embodiments, a plurality of reels can be attached to one reel shaft and run in multiple reels to increase processing efficiency. In this case, the metal strip and the strip mask can each be multi-striped, or only one can be made multi-striped, and the other can be preformed into a corresponding wide strip. .

Further, it is also possible to simply wind the metal strip and the strip mask onto a shaft and let it out without using a reel.

Furthermore, the direction in which the evaporated aluminum is thrown can be not only vertically upward, but also horizontally or diagonally, and in this case, it goes without saying that each device should be arranged corresponding to that direction.

In addition, in any of the embodiments described in section 2, when winding the metal strip 32, appropriate cooling is provided between the presser roller 42 and the take-up reel 34 so that the vapor-deposited film does not adhere to the back surface of the metal strip 32. A device (not shown) may be provided to cool and wind the metal strip 32, or a suitable spacer may be attached to the metal strip 32.
It is best to insert it in between and wind it up.

Furthermore, as the material of the strip mask 48, since the vapor deposition process involves a thermal process, a material having a coefficient of thermal expansion comparable to that of the metal strip 32, preferably a material made of the same material as the metal strip 32 is used. This results in the formation of an aluminum coating with good positioning accuracy.

Further, the metal to be vapor-deposited is not limited to aluminum or aluminum alloy, but any metal that can be vapor-deposited can be applied.

As described above, according to the method and apparatus of the present invention, a vapor deposited film of a desired shape can be continuously and efficiently formed at a desired position of a metal strip with high positioning accuracy, and the cost can be reduced. play.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of the drawing]

FIGS. 1(a) and 1(b) are explanatory diagrams showing the portions of the lead frame where the vapor deposition film is formed. FIG. 2 is a schematic explanatory diagram showing an embodiment of the device of the present invention;
FIG. 3 is a plan view of a metal strip, FIG. 4 is a plan view of a strip mask, and FIG. 5 is a plan view showing a state in which a vapor-deposited film is formed on the metal strip. FIG. 6 and FIG. 7 are schematic explanatory diagrams showing other embodiments. 10.10', , evaporation film area, 12.12', .
. Lead frame, 20. , , Vacuum container. 22. , evaporation pot, 24. ,,Heating heater. 26.,, one cover, 28. ,,slit. 30, , feeding reel, 32. ,,metal strip. 34, take-up reel, 360. , reference hole. 38, Sprocket, 40, 42, 4410. Presser roller, 46. ,, 1J-le for feeding. 48,, band mask, 50. ,, winding reel, 5
2. , , reference hole, 54. ,,Aperture. 56, Sprocket, 60. ,, preheating heater. Patent applicant Shinko Electric Industry Co., Ltd. Figure 2 32 36 Figure 6

Claims (1)

[Claims] 1. In a vacuum container equipped with vapor deposition means including an evaporation pot, a metal strip and openings having the shape of the vapor deposition film to be applied to the metal strip are spaced at regular intervals in the longitudinal direction. A strip mask formed with the above steps is run in close contact at least in the evaporation region, and the material to be evaporated from the evaporation pot passes through the opening and is deposited on the metal strip. A method for partial vacuum deposition of a metal strip, characterized in that the metal strip and the strip mask are each wound separately. 2. A method for partial vacuum deposition of a metal strip according to claim 1, wherein the strip mask is made of a metal having substantially the same coefficient of thermal expansion as the metal strip. 3. A vacuum container connected to a suitable vacuum device, an evaporation pot that houses an evaporation source of aluminum or the like placed inside the vacuum container, a heating device that heats this evaporation source, and both sides of this evaporation pot. a metal strip feeding means and a metal strip winding means respectively located on both sides of the evaporating pot; a strip mask feeding means and a strip mask winding means respectively arranged on both sides of the evaporation pot; At least a metal strip that is paid out from the metal strip delivery means and wound up on the metal strip winding means and a strip mask that is paid out from the strip mask delivery means and wound up on the strip mask winding means are vapor-deposited. constant speed drive for driving the metal strip and the strip mask at a constant speed and in synchronization at least within the vapor deposition region with press rollers located on both sides of the evaporation pot so as to be in close contact with each other within the vapor deposition region; A partial vacuum evaporation device for metal strips consisting of a mechanism. 4. The partial vacuum evaporation apparatus for metal strips according to claim 3, which uses an alignment sprocket that meshes with the metal strips and the strip mask as means for synchronizing the metal strips and the strip mask.