JP3773573B2 - Substrate transport method and hybrid integrated circuit device manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for transporting a substrate and a method for manufacturing a hybrid integrated circuit device, and more particularly to a method for transporting substrates having different irregularities or thicknesses without affecting the surface, and a predetermined amount on the surface of the hybrid integrated circuit substrate. The present invention relates to a method for leaving the etching solution. Furthermore, in the latter, when Ni is applied on Cu, the Ni wrinkles are removed to prevent the occurrence of nickel whiskers.
[0002]
[Prior art]
In general, in a hybrid integrated circuit device, for example, Cu may be used as a conductive path. FIG. 7 shows an example thereof. For example, a conductive path (2) for achieving a desired circuit is formed on a substrate (1) having at least an insulating surface, and this conductive path (2) or an integral or island is formed. The circuit is realized by mounting a semiconductor chip, a chip resistor, or the like on conductive lands that are independently formed.
[0003]
Here, the substrate (1) is made of Al metal, the surface is anodized to produce aluminum oxide (3), and an epoxy resin (4) is deposited on the entire surface in consideration of adhesion to the conductive path. ing. The conductive path is thermocompression bonded by a so-called hot press.
In the above configuration, Ni (6) is plated on the surface in consideration of the oxidation prevention of Cu (5) and the bonding property of the fine metal wires.
[0004]
On the other hand, there are two main types of etching, dry etching and wet etching, but wet is the mainstream in consideration of throughput. In general, when a metal of several μm to several tens of μm is dry, what takes several hours or more can be etched in several minutes to several tens of minutes if performed by shower type wet etching.
In particular, when Cu and Ni are deposited on the entire surface and wet etching is performed with a ferric chloride (FeCl2) etchant, since Cu has a higher etching rate, Ni ridges (7) are formed as shown in FIG. Is done.
[0005]
On the other hand, during the manufacturing process, brushing is performed in consideration of removal of resist dust and other dusts and improvement of bonding properties because the Ni surface is flat. That is, dust is removed by this brushing, and the surface of Ni becomes rough.
However, as shown in FIG. 7, since a Ni ridge is provided, the bristle of the brush hits this ridge, generating Ni whisker (8), causing a short circuit between the conductive paths (2), and film peeling. Etc. were generated.
[0006]
In addition, when the area other than the Ni film formation region is covered with a resist and Ni is selectively deposited by electrolytic plating, current concentrates around the resist, and when the resist is removed, protrusions are generated around the Ni pattern. There was also a problem that this deteriorated bonding properties.
Therefore, the countermeasures as disclosed in JP-A-7-147476 have been taken. That is, a conductive path (see FIG. 2) is first formed by wet etching using a shower that is a forced supply method, and then, for example, an etching solution (an aqueous solution mainly containing ferric chloride) as shown in FIG. Ni is selectively removed by dipping the substrate (1) and selectively removing the Ni film in a state in which a protective film (copper chloride) combined with one element of the etchant, for example, chlorine Cl, is formed on the side surface of the Cu (5). Had been removed.
[0007]
In other words, when wet etching is performed by the forced supply method, this protective film peels off, and a new Cu surface is always exposed and etching proceeds. However, when the liquid is kept in a dipping state, this protective film adheres to the side of Cu. This keeps the state as it is, and enables selective etching of Ni.
Further, as described above, since selective etching of Ni becomes possible, protrusions formed around the Ni pattern can also be removed.
[0008]
On the other hand, there has been a technique as disclosed in Japanese Utility Model Publication No. 5-44080 for transporting a substrate. That is, as shown in FIG. 6, the substrate 20 is held and transported by a pair of upper and lower sponge rollers 33, 33. Since the material is sponge, it is possible to transport substrates having different thicknesses or uneven substrates. is there.
[0009]
[Problems to be solved by the invention]
The protective film is presumed that CuClx (X = 1, 2) remains on the surface of Cu rather than a film, and a liquid film remains in a layer form rather than a film. . Therefore, if the substrate is put into a stationary etching solution, Cu is initially etched, but then CuClx is generated, and the protective solution layer remains on the side wall of Cu, so that the etching solution attacks nickel. The amount will increase. However, when the amount of ferric chloride is large, the relative ratio is a difference in degree. Again, Cu is attacked, and Cu is selected more than Ni. Although the etching rate is lower than that of Cu, Ni has been etched, so it will eventually disappear, but the long etching time is still a problem.
[0010]
Further, since the roller is a sponge, it is flexible and abuts on substantially the entire surface except for a narrow recessed portion between the wirings. For this reason, when it is used for conveyance in various processes including the etching process, there is a problem in that the wiring and the elements fixed between the wirings are damaged.
[0011]
[Means for Solving the Problems]
The present invention has been made in view of the above-mentioned problems, and is made of a material such as EPT rubber (ethylene propylene terpolymer), and has a concave and convex roller as shown in FIG. By controlling the height of the roller, flexibility is given to the roller itself, and since the roller does not contact the entire surface of the substrate due to the unevenness, the circuit components of the substrate are not damaged.
[0012]
Secondly, when the etching liquid is cut while rolling the roller, the etching liquid is cut while the etching liquid is taken into the space between the indented portion of the roller and the substrate when the roller contacts the substrate. A certain amount of etching solution can remain on the surface. In addition, because the pressure of the roller, or unevenness and protrusions are provided on the roller, and the etchant can be controlled by the size of the unevenness and protrusions, Ni soot can be selectively etched by selecting optimum conditions. .
[0013]
As shown in FIG. 5, the third and fourth methods do not employ a system in which the etching solution is very much with respect to the etching material. If the etching solution is reduced, ferric chloride reacts and disappears immediately, and CuClx (X = 1 2) became rich, and it was determined that soot was removed because the reaction product of Ni had a higher etching rate than Cu. Therefore, as shown in FIG. 6, the roller was brought into contact with the substrate surface and rolled to cut the etching solution. If the etching solution remains on the substrate surface due to the pressure of the roller and the ferric chloride reacts and disappears immediately, Ni す ぐ can be selectively etched by this etching solution.
[0014]
However, due to the relationship between the surface tension of the contact interface between the roller and the etchant (the cause is not clear), the etchant between the conductive paths is sucked into the roller as shown by the S curve in FIG. Since the amount is smaller than that of the etching surface, the etching surface is schematically shown as a convex S downward.) On the contrary, there is a problem that the etching solution is not sufficient and Ni? Therefore, it came to the 5th means.
[0015]
Fifthly, as shown in FIG. 3, when the etching solution is left mainly between the wirings, since the roller has irregularities, the etching solution in the space between the substrate and the recessed portion is added between the wirings. Therefore, the etching solution applied between the wirings can be controlled by the size of the unevenness. Therefore, etching of the side walls of Cu occurs at first, but the amount of ferric chloride aqueous solution is small, so that the relatively consumed CuClx (X = 1, 2) can relatively attack Ni and remove soot. it can.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
First, the conveying method will be described with reference to FIGS.
FIG. 6 shows a conventional example of the transport method, which is described in detail in Japanese Utility Model Publication No. 5-44080. If it roughly explains, since it conveys with a roller like a sponge, it passes between a pair of upper and lower rollers, and a substrate with unevenness and a substrate with different thickness can be conveyed in parallel or in series.
[0017]
However, this roller abuts on all surfaces except for the recessed portion (etched portion) between the wirings, so that there is a problem that the wiring is scratched depending on the pressure applied by the roller.
According to the present invention, in this transport method, the roller is provided with a protruding portion, and the contact portion of the substrate can be greatly reduced as compared with the conventional one (FIG. 6).
[0018]
Here, by using a material such as EPT rubber (ethylene / propylene / terpolymer) and a roller with irregularities as shown in FIG. 3, the pitch of the irregularities, especially by controlling the height from peak to valley, The roller itself is flexible, and the roller does not come into contact with the entire surface of the substrate due to the unevenness, so that the circuit component of the substrate is not caught or scratched. Therefore, it is effective in all processes for transporting the substrate.
[0019]
Next, a method for leaving the etching solution using this roller will be described. Here, in the description of the previous embodiment, FIG. 6 was publicly known, but a method of using this to cut an etching solution on the surface of the substrate and leaving the etching solution on the substrate surface by a predetermined amount is novel. Therefore, the manufacturing method of the hybrid integrated circuit device will be described using the two types of rollers shown in FIGS.
[0020]
First, the substrate structure will be described with reference to FIG. 4. At least the surface of the substrate has an insulating property (20), and a conductive path (21) is formed thereon. This substrate (20) is made of an Al substrate here, and its surface is formed with aluminum oxide (22) by anodic oxidation. Further, considering the adhesiveness with the conductive path (21), an epoxy resin (23) Is coated. However, as long as at least the surface is insulated, and a wiring material can be directly formed by another method (for example, sputtering or the like), a ceramic, a printed board, a glass board, or the like may be used.
[0021]
The conductive path (21) has a two-layer structure, and the lower first conductive path (24) is made of Cu, and here has a thickness of 35 μm and is the main part of the conductive path (21). On the first conductive path (24), a second conductive path (25) made of Ni having a lower etching rate than this conductive path, for example, about several μm to 10 μm, actually 5 μm in this case, is deposited. Has been. As will be described in detail later, the first conductive path (24) and the second conductive path (25) are wet-etched with an etchant (aqueous ferric chloride solution) having a higher etching rate. ) At the same time, the first conductive path (24) is inevitably selected and undercut, and a ridge (7) is formed as shown in FIG. 7, but the method of the present invention is adopted. As a result, Ni wrinkles are removed, and they are arranged inside the Cu pattern as shown in FIG.
Therefore, as explained in the prior art, even if brushing is performed to remove resist dust and other dust, and to roughen the Ni surface, Ni wrinkles are not formed, so Ni whistle does not occur and short-circuiting is suppressed. can do.
[0022]
The conductive path 21 is formed in a predetermined pattern to achieve a predetermined circuit, and passive elements such as a chip resistor and a chip capacitor, and active elements such as a bare transistor chip and an LSI chip are electrically connected. ing. In particular, the active element is fixed to the island-shaped conductive path through a heat sink or the like as necessary. Since there are electrodes on the chip surface, the fine metal wires are electrically connected to other conductive paths by wire bonding. In addition, a part of the circuit is extended around the semiconductor substrate (20) to form a lead terminal, and the lead is electrically connected thereto via solder.
[0023]
Further, when the circuit scale is large, an insulating flexible sheet provided with a second-layer wiring may be attached on these semiconductor substrates. A pre-patterned or non-patterned copper foil may be attached to the entire surface of the substrate, and then the flexible sheet copper foil may be patterned. In this case, it goes without saying that the present invention can be adopted when Ni is coated on the Cu pattern. Of course, the passive element and the active element are also formed in the second-layer wiring, and a predetermined circuit is realized including these elements in the first and second layers.
[0024]
The single-layer or multi-layer substrate described above is sealed. It may be sealed with a metallic can or may be resin molded. The case material may be applied to the substrate, and the resin may be injected therein.
Next, the manufacturing method will be described.
First, an Al metal substrate (20) is prepared, the surface thereof is anodized to form an aluminum oxide (22), an epoxy resin (23) is formed, and the adhesiveness of this resin is utilized. A Cu foil (24) is press bonded to the entire surface, and a Ni layer (25) is formed on the entire surface by plating. Here, a copper foil whose entire surface is coated with Ni may be attached in advance. Ni may be formed by a method other than plating (see FIG. 1 above).
Subsequently, a photoresist (30) is formed in a region where the conductive path (21) is formed by photolithography, and wet etching is performed so that a new etchant is always supplied to the surface to be etched. This method of supplying a new etchant to the surface to be etched and simultaneously supplying a flow to the etchant in order to remove the reactant is tentatively referred to as a forced supply method. There are various methods such as a shower and a method of circulating in the liquid layer. Here, the etchant is ferric chloride, and a shower is adopted as a forced circulation method. Since the etching rate R of ferric chloride is R (Cu)> R (Ni), soot (7) as shown in FIG. One conductive path (24) and a second conductive path (25) are formed. (See Figure 2 above)
Subsequently, there is a step of rolling the roll 23 on the surface of the substrate 20 to cut off the etching solution and at the same time leave a certain amount.
[0025]
This step is a feature of the present invention, and the most important point is that the etching solution is left between the wirings of the metal substrate with a roll and the etching is performed with a stationary etching solution unlike the forced supply method.
First, the stationary etchant will be described. That is, when a stationary etching is performed, the reactant remains on the etching surface of Cu, and this reactant acts as a protective film, making it difficult for the etchant to attack Cu and relatively easily etching Ni. Here, the meaning expressed as “still” will be described. In the case of etching Cu in FIG. 2, the etching solution is continuously supplied to the etching surface by means such as a shower or a screw, and the etching rate becomes very high. Therefore, the etching up to FIG. 2 is named the forced supply method in the sense that it is dynamically circulated from the meaning of the means.
[0026]
On the other hand, if the forced circulation is weakened, the layer serving as the protective film is not destroyed, so that a fresh etching solution is not supplied to the surface of Cu. In other words, it was expressed as static against forced circulation.
Although it is better that the etching solution is completely stationary, it is difficult to rest in the manufacturing process, so if the protective film moves only slightly, it can be said that the etching solution is stationary with respect to the dynamic. Add. In other words, if the protective film does not cause destruction, it is considered to be included in the stationary category.
[0027]
In addition, this protective film is not clear, but rather than a film, it is presumed that CuClx (X = 1, 2) remains on the surface of Cu and the liquid film remains in a layered state. Yes. Therefore, if the substrate is put into a stationary etching solution, the protective solution layer produced by Cu etching remains on the side walls of Cu, so that the nickel attack amount of the etching solution is relatively increased. When the amount of ferric chloride is large, the relative ratio is a difference in degree. Again, Cu is attacked, and Cu is relatively more selectively etched than Ni, and Ni soot is difficult to etch. understood.
[0028]
Therefore, unlike the conventional example of FIG. 5, if the etching solution is reduced without reducing the etching solution to the etching material, the ferric chloride immediately reacts and disappears, and CuClx (X = 1, 2). ) Became rich, and it was determined that soot was removed because Ni had a higher etching rate than Cu.
Therefore, it was considered that the etching solution should be left on the surface of the substrate, and as shown in FIG. 6, it was rolled while the roller 33 was in contact with the surface of the substrate (1), and the etching solution was cut.
[0029]
Here, the amount of the etching solution placed on the substrate may be limited by rolling the one that was placed at the time of forced supply in FIG. 2, or may be rolled by separately loading the etching solution.
As shown in FIG. 6, the amount of the etching solution placed on the substrate 20 can be controlled by the contact strength of the roller 33. Specifically, as in the hatched area shown between the wirings 21, other excess etching liquid can be cut while the etching liquid taken in between the substantial wirings remains.
[0030]
Therefore, the amount of the etching solution can be limited and the CuClx is generated excessively, so that Ni can be selectively etched over time.
However, the contact interface between the roller 33 and the etching solution is due to the relationship between the surface tension (the cause is not clear), and the etching solution between the conductive paths is absorbed by the roller during rotation (the amount is reduced in the drawing). , And the etching surface is schematically shown as convex downward.) On the contrary, there was a problem that the etching solution was insufficient and it was not possible to completely remove all Ni. In addition, although the length of the cocoon was reduced, there was a problem that it was difficult to remove the cocoon stably.
[0031]
Therefore, when the etching solution remains mainly between the wirings, an uneven roller as shown in FIG. 3 is used, and the etching solution between the substrate and the recessed portion of the roller is placed between the wirings, as shown in FIG. The etching solution can be increased more than the remaining amount. In other words, the etching solution can be controlled to remain by the size of the unevenness, the flexibility of the roller, and pressurization. Therefore, although there is a ferric chloride etchant that etches the side walls of Cu at first, since the amount is small as a whole, the remaining CuClx (X = 1, 2) is used to relatively attack Ni. And you can get rid of sputum.
[0032]
Here, the roller 32 is only on the upper surface of the substrate, but a roller may be disposed below as shown in FIG. Since it is not necessary to cut off the etching solution for the lower roller, it is not necessary to prepare an uneven surface. The material of the roller is EPT (ethylene propylene terpolymer) rubber, and the irregularities are just like a combination of multiple abacus balls, the pitch is about 3 mm, the height from the mountain to the valley is It is about 1 mm. In addition, the valley V in FIG. 3 has a shape that returns to the original position after one rotation, but may have a spiral shape. Moreover, the shape which an uneven | corrugated | grooved part is dotted in an island shape like the confectionery of Japanese sweets may be sufficient.
[0033]
Next, the etching solution is removed with, for example, pure water, and then brushing is performed as described in the conventional example. Therefore, as shown in FIG. 4, the Ni soot can be finally removed and patterning can be performed, so that the occurrence of Ni mustache can be suppressed.
After this, a thick film resistor is formed by screen printing, or a chip-like passive element or active element is electrically connected via solder, silver paste, solder paste, etc. Wire bonding with. Further, if necessary, a lead is attached and sealed.
[0034]
The right wiring 21 may surround the periphery of the substrate (20) and be provided with a dam portion made of the same material as that of the conductive means, as indicated by D, because the etching solution flows out.
[0035]
【The invention's effect】
As is clear from the above description, since the roller is provided with irregularities and the substrate is transported using this roller, the roller does not contact the entire surface of the substrate and damage to the substrate is reduced.
Second, by rolling a roller on the substrate surface, a certain amount can be left while cutting off the etching solution on the substrate surface. Therefore, when etching is performed only with the etching solution remaining on the substrate, it can be easily performed by a very simple method. If flexible, a plurality of substrates having different substrate thicknesses can be rolled at a time, and an etching solution can be left.
[0036]
Thirdly, the etching solution can be left by rolling between the wirings in which the Ni layer having a ridge is laminated on Cu, and the amount of ferric chloride etching solution between the wirings is a limited amount. It immediately reacts with Cu to become CuClx rich and can remove Ni soot.
Fourth, if the roller is provided with irregularities, the etching solution can be taken into the space between the substrate and the recessed portion of the roller, and this etching solution can be left on the substrate. Therefore, the etching amount can be increased as compared with the case without unevenness, and the amount can be controlled by the unevenness size. In other words, the wiring interval and wiring thickness vary for each model, and the etching amount needs to be controlled, but the amount can be controlled by the size of the unevenness.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view illustrating a production method of the present invention.
FIG. 2 is a cross-sectional view illustrating the manufacturing method of the present invention.
FIG. 3 is a cross-sectional view illustrating the manufacturing method of the present invention.
FIG. 4 is a cross-sectional view illustrating the manufacturing method of the present invention.
FIG. 5 is a cross-sectional view illustrating a conventional manufacturing method.
FIG. 6 is a diagram for explaining a substrate transport method or etching liquid draining.
FIG. 7 is a cross-sectional view illustrating a conventional hybrid integrated circuit device.
[Explanation of symbols]
20 Substrate 21 Conductive path 24 Cu conductive path 25 Ni conductive path 31 庇 32, 33 Roll

Claims (5)

Prepare a hybrid integrated circuit board having Cu wiring with nickel formed on the upper surface, forming a ridge ,
The surface of the hybrid integrated circuit substrate is immersed in the etching solution at the time of patterning, or the etching solution is immersed in this step,
Rolling a roller on the upper surface of the hybrid integrated circuit substrate, cutting off the etchant on the upper surface of the hybrid integrated circuit substrate, and etching the cage-shaped nickel with the etchant substantially remaining between the patterns A method for manufacturing an integrated circuit device. A step of preparing a hybrid integrated circuit board to which Cu having nickel provided thereon is attached;
A step of immersing the hybrid integrated circuit board in an etching solution mainly composed of ferric chloride and etching it into a predetermined pattern;
Rolling the upper surface of the hybrid integrated circuit board with a roller and cutting the etchant so that the etchant for the hybrid integrated circuit board or the etchant that has been immersed again remains between the patterns;
And a step of etching the cage-like nickel remaining on the Cu pattern with an etching solution substantially remaining between the patterns. The method of manufacturing a hybrid integrated circuit device according to claim 1, wherein the roller has irregularities on the entire surface. The method of manufacturing a hybrid integrated circuit device according to claim 1, wherein at least a surface of the hybrid integrated circuit substrate is subjected to an insulation process. The method of manufacturing a hybrid integrated circuit device according to claim 1, wherein a material of the roller is EPT rubber (ethylene propylene terpolymer).

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