JP4295523B2 - Multilayer wiring board - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a multilayer wiring board, and more particularly, to a multilayer wiring board used for a semiconductor element housing package for housing a semiconductor integrated circuit element, a probe card for electrically inspecting a semiconductor integrated circuit, and the like. Is.
[0002]
[Prior art]
2. Description of the Related Art In recent years, in semiconductor integrated circuits, the number of terminals formed on a semiconductor substrate has increased and the pitch of terminals has been reduced due to higher integration of semiconductor elements and an increase in the number of processing signals. As a result, the pitch of the connection terminals of the package for housing the semiconductor element that houses the semiconductor integrated circuit element and the probe of the probe card that performs electrical inspection of the semiconductor integrated circuit is also required.
[0003]
In response to this demand for narrow pitches, in the package for housing semiconductor devices, the mounting form of the semiconductor devices is changed from wire bonding connection to flip chip connection, and the probe card is a cantilever type, and needle-like probes are finely latticed. It has changed to something arranged in a shape.
[0004]
In addition, the structure of the multilayer wiring board used in the semiconductor element storage package and the probe card is formed by forming a wiring conductor layer obtained by patterning a copper foil on an insulating layer obtained by impregnating and curing an organic resin on a substrate made of glass fiber. Multi-layer consisting of a thin insulating layer and a wiring conductor layer on the top surface of the substrate, which is excellent in narrowing the pitch of the wiring conductor layer and can be arranged in a fine lattice pattern. It is changing to a build-up type multilayer wiring board in which a wiring part is formed.
[0005]
Such a build-up type multilayer wiring board is made of an epoxy resin, a polyimide resin, or the like on the upper surface of the board, and is formed by applying a resin precursor by a curtain coating method, a spin coating method, or the like and then heat-curing the insulating layer. And a structure in which wiring conductor layers made of a metal such as copper or aluminum are alternately laminated in multiple layers by adopting a thin film formation technique such as a plating method or a vapor deposition method and a photolithography technique. It has become.
[0006]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-163520 [Patent Document 2]
Japanese Patent Application Laid-Open No. 11-38044
[Problems to be solved by the invention]
However, in a multilayer wiring board having a multilayer wiring portion composed of an insulating layer and a wiring conductor layer as described above, the thickness of the insulating layer made of an organic resin is substantially uniform on the unevenness of the surface on which the organic resin precursor is applied. Therefore, a step is likely to occur on the surface of the insulating layer formed thereon due to the convex portion of the wiring conductor layer formed on the insulating layer. Further, when the insulating layer is multilayered, the surface of the insulating layer formed on the uppermost surface of the multilayer wiring board may have a complicated uneven shape reflecting the unevenness in each layer.
[0008]
When a semiconductor substrate is mounted on the top surface of a wiring conductor layer formed on the top surface of a multilayer wiring board having such a concavo-convex shape, the surface roughness of the insulating layer formed on the top surface of the multilayer wiring board is absorbed. For example, it is necessary to adjust the height of the solder for connecting the semiconductor substrate formed on the wiring conductor layer so as to be parallel to the surface of the semiconductor substrate. Since the solder height more than necessary is necessary for the adjustment, there is a problem that the narrow pitch of the wiring conductor layer on the uppermost surface of the multilayer wiring board is hindered as a result.
[0009]
Also, when the probe is brought into contact or connected like a probe card, the height variation of the probe tip increases due to the height variation of the upper surface of the wiring conductor layer, and the contact pressure of the probe with respect to the terminal of the semiconductor substrate is increased. There was a problem that the variation occurred and the connection resistance was likely to fluctuate.
[0010]
Furthermore, if the height of the upper surface of the wiring conductor layer varies, there is a problem that the pressure is concentrated on a specific probe due to the variation in the contact pressure of the probe, which tends to shorten the life of the probe.
[0011]
The present invention has been made in view of the above-described problems in the prior art, and the object thereof is to provide a narrow pitch of the wiring conductor layer in which the insulating layer formed on the uppermost surface of the multilayer wiring board has a high flatness. An object of the present invention is to provide a multilayer wiring board that can cope with the manufacturing process.
[0012]
[Means for Solving the Problems]
In the multilayer wiring board of the present invention, the insulating layer and the wiring conductor layer are laminated in multiple layers, and the wiring conductor layers positioned above and below are connected by arranging a through conductor in a through hole provided in the insulating layer therebetween. Ri formed by the insulating layer has a recess on the top surface includes a first insulating layer made of ceramics, the upper into the through hole of Rutotomoni the recess is laminated on the upper surface of the first insulating layer a second insulating layer made of an organic resin and, and a third insulating layer made of the first insulating layer lower surface stacked organic resin, the wiring conductor layer in the recess of the first insulating layer The lower surface of the metal layer is embedded through the second insulating layer.
[0013]
Moreover, the multilayer wiring board of the present invention preferably has a diffusion prevention layer formed on the entire surface of the through hole and the recess provided in the insulating layer in the above configuration.
[0014]
According to the multilayer wiring board of the present invention, the lower surface of the wiring conductor layer penetrates the second insulating layer made of organic resin and is embedded in the upper surface of the first insulating layer made of ceramics. Since part of the layer is embedded in the insulating layer, the amount of protrusion of the wiring conductor layer protruding from the insulating layer can be reduced compared to the case where the wiring conductor layer is disposed on the upper surface of the insulating layer as in the past. In addition, since the lower surface of the wiring conductor layer is embedded in the first insulating layer made of ceramics, the wiring conductor layer can be firmly fixed to the insulating layer. Further, when the next insulating layer is laminated on the upper surface by the press working method, the first insulating layer made of ceramic is the third insulating layer made of organic resin even when the next insulating layer is heated and pressed. Since the wiring conductor layer is firmly fixed to the insulating layer, the third insulating layer protrudes from the lower insulating layer according to the shape of the first insulating layer. By deforming so as to wrap, the upper surface thereof can be processed according to the original shape of the first insulating layer. Thereby, the influence of the protrusion of the lower wiring conductor layer on the surface of the insulating layer formed on the uppermost surface of the multilayer wiring board can be suppressed, and the surface can be made flat.
[0015]
Further, if the second insulating layer and the third insulating layer are formed of a thermoplastic resin, when the insulating layers having the second and third insulating layers on the upper and lower surfaces are multi-layered, a hot press is used. By the processing method, the second and third insulating layers flow and can be easily bonded to the multilayer. At the same time, when the next insulating layer is further laminated on the upper surface by the press working method, the first insulating layer is harder than the second and third insulating layers even during the next hot press working. Since the conductor layer is firmly fixed to the insulating layer, the third insulating layer is deformed so as to wrap around the protruding portion of the wiring conductor layer protruding from the lower insulating layer according to the shape of the first insulating layer. Thus, the upper surface can be processed according to the original shape of the first insulating layer. Thereby, the surface of the insulating layer formed on the uppermost surface of the insulating layer can be easily and stably made flat.
[0016]
As a result, the wiring conductor layer formed on the flat top surface of the multilayer wiring board formed by laminating a plurality of insulating layers and wiring conductor layers in multiple layers and the connection portion of the semiconductor substrate can be arranged in parallel. Since it becomes easy, it becomes unnecessary to adjust the height of the solder for connecting the semiconductor substrate. As a result, the multilayer wiring board can cope with the narrow pitch of the wiring conductor layer with the flatness of the insulating layer formed on the uppermost surface of the multilayer wiring board being high.
[0017]
When the multilayer wiring board of the present invention is used as a probe card, a wiring conductor layer and a probe formed on the uppermost surface of the multilayer wiring board formed by laminating a plurality of insulating layers and wiring conductor layers. Variation in the height of the wiring, and the load applied to the probe during the inspection of the semiconductor integrated circuit can be prevented from being concentrated on a part of the upper surface of the wiring conductor layer. This can eliminate the problem of shortening the service life. Thereby, it becomes a multilayer wiring board excellent in electrical connectivity which can make contact resistance with a probe stable for a long time.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a multilayer wiring board of the present invention will be described in detail with reference to the drawings.
[0019]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a multilayer wiring board according to the present invention, and FIG. 2 is an enlarged cross-sectional view of a main part showing a state around a wiring conductor layer in the multilayer wiring board shown in FIG. In these drawings, 1 is an insulating layer, 2 is a wiring conductor layer, 3 is a first insulating layer as a part of the insulating layer 1, 4 is a second insulating layer as a part of the insulating layer 1, 5 is A third insulating layer as a part of the insulating layer 1, 6 is a through hole, and 7 is a through conductor.
[0020]
The insulating layer 1 is composed of a second insulating layer 4 stacked on the upper surface of the first insulating layer 3 and a third insulating layer 5 stacked on the lower surface of the first insulating layer 3. The insulating layer 1 has a function of electrically insulating the upper and lower wiring conductor layers 2, and among them, the first insulating layer 3 is made of ceramics and serves as a basic skeleton of the insulating layer 1. It functions as a support member that supports the wiring conductor layer 2 together with the insulating layer 5.
[0021]
The first insulating layer 3 is made of an oxide ceramic such as an aluminum oxide sintered body or a mullite sintered body, or an aluminum nitride sintered body having an oxide film on its surface, a silicon carbide sintered body or the like. It consists of oxide ceramics, and also a glass ceramic sintered body. The second insulating layer 4 and the third insulating layer 5 are made of polyimide resin, polyamideimide resin, siloxane-modified polyimide resin, siloxane-modified polyamideimide, bismaleimide triazine resin, or the like.
[0022]
For the insulating layer 1, for example, a ceramic layer having a thickness of about 20 to 100 μm is prepared as the first insulating layer 3. Then, an organic resin varnish material is applied to both surfaces of the first insulating layer 3 as a second insulating layer 4 and a third insulating layer 5 to a dry thickness of about 3 to 20 μm using a doctor blade method or the like and dried. Thus, the insulating layer 1 is formed.
[0023]
Further, the insulating layer 1 is laminated in multiple layers by bonding it to another insulating layer 1 or the wiring conductor layer 2 with the third insulating layer 5 side as an adhesive surface by applying heat and pressure using a hot press device. A multilayer wiring board is formed.
[0024]
With such a configuration, since the first insulating layer 3 is hard at the time of pressing when forming the multilayer wiring board by laminating the insulating layer 1 and the wiring conductor layer 2, the insulating layer 1 Since the first insulating layer 3 of the other insulating layer 1 is hard, the convex portion generated by the wiring conductor layer 2 and the like disposed on the upper surface side of the insulating layer 1 when the other insulating layer 1 is laminated thereon is left as it is. The third insulating layer 5 is deformed so as to absorb the stress generated at the contact surface with the convex portion due to its softness, so that the second insulating layer 1 between the upper and lower insulating layers 1 is retained. Since the wiring conductor layer 2 can be embedded in the insulating layer 4 and the third insulating layer 5, as a result, the upper surface of the laminated insulating layer 1 can be easily and stably made flat. become.
[0025]
As a combination of the first insulating layer 3, the second insulating layer 4, and the third insulating layer 5, for example, the first insulating layer 3 is an aluminum oxide sintered body and the second insulating layer 3 is used. There is a combination in which the layer 4 and the third insulating layer 5 are siloxane-modified polyamideimide resins. According to this combination, the siloxane-modified polyamideimide resin has good adhesion to the aluminum oxide sintered body of the first insulating layer 3 and has high heat resistance. The soldering heat resistance when the board is mounted on a printed board or the like becomes good.
[0026]
The first insulating layer 3 is a glass ceramic sintered body having a thermal expansion coefficient of 9 to 15 × 10 ⁻⁶ / ° C., and the second insulating layer 4 and the third insulating layer 5 are thermoplastic polyimide resins. It is good to leave. In the case of this combination, the heat resistance is high, and the difference in thermal expansion coefficient between the first insulating layer 3 and the second insulating layer 4 and the third insulating layer 5 can be reduced, so that the insulating layer The internal stress of 1 can be lowered, and thereby the overall warpage of the multilayer wiring board can be reduced.
[0027]
Further, each insulating layer 1 is provided with a wiring conductor layer 2 and the wiring conductor layers 2 positioned above and below the insulating layer 1 are electrically connected to each other so that the through-holes provided in the insulating layer 1 are provided. A through conductor 7 is embedded in the hole 6. These wiring conductor layers 2 and through conductors 7 adopt thin film formation techniques such as sputtering, vapor deposition, plating, etc., of metal materials such as copper, gold, aluminum, nickel, chromium, molybdenum, titanium, and alloys thereof. Can be formed.
[0028]
The through conductor 7 may be formed separately from the wiring conductor layer 2, but it is preferable that these are formed at the same time in that the number of processes can be reduced, and also in terms of reliability of electrical connection between them. It will be good. In addition, when the wiring conductor layer 2 and the through conductor 7 are integrally formed, the wiring conductor layer 2 and the through conductor 7 are mainly formed by using an electrolytic plating method so that each can be adjusted to a desired thickness and formed by a plating film. It is good to keep.
[0029]
In the multilayer wiring board of the present invention, the lower surface of the wiring conductor layer 2 penetrates the second insulating layer 4 together with the lower portion thereof and is embedded in the upper surface of the first insulating layer 3. Since the lower surface of the wiring conductor layer 2 is embedded in the upper surface of the first insulating layer 3 in this way, a part of the wiring conductor layer 2 is embedded in the insulating layer 1, so that the conventional multilayer wiring In the substrate, it is possible to reduce the protruding amount of the wiring conductor layer 2 that protrudes greatly on the upper surface of the insulating layer 1, and to flatten the surface of the insulating layer 1 laminated thereon, and The surface of the insulating layer formed on the uppermost surface of the wiring board can also be flat. Further, since the first insulating layer 3 is hard and the lower surface of the wiring conductor layer 2 can be firmly fixed to the upper surface thereof, the reliability of the bonding of the wiring conductor layer 2 to the first insulating layer 3 is improved. In addition, since the positional deviation of the wiring conductor layer 2 due to the heat treatment when the insulating layer 1 is multilayered can be suppressed, the positional accuracy of the wiring conductor layer 2 is improved.
[0030]
Furthermore, the wiring conductor layer 2 is optimally formed so as to be completely embedded in the second insulating layer 4. As a result, the surface of the insulating layer 1 on which the wiring conductor layer 2 is formed and the surface of the wiring conductor layer 2 can be completely flattened, and the insulating layer 1 is further laminated thereon. The uppermost surface of the formed multilayer wiring board can also be made completely flat.
[0031]
As a method for forming the wiring conductor layer 2 and the through conductor 7, for example, first, a concave portion having a wiring pattern shape for the wiring conductor layer 2 is formed on the surface of the insulating layer 1 and the through hole 6 for the through conductor 7 is formed.
[0032]
The recess for the wiring conductor layer 2 removes a part of the upper surface side of the second insulating layer 4 and the first insulating layer 3 from the upper surface side of the insulating layer 1 by, for example, a metal film as a mask by oxygen plasma treatment or sand blast treatment. It is formed by doing. Further, the through-hole 6 is formed by removing the first insulating layer 3 and the third insulating layer 5 at predetermined positions of the concave portion for the wiring conductor layer 2 using, for example, laser or sand blasting.
[0033]
Next, an underlying conductor layer is formed by depositing chromium, molybdenum, titanium or the like as a diffusion prevention layer (barrier layer) on the entire upper surface of the insulating layer 1 and having a copper layer as a main component on the insulating layer 1 side of the copper layer. Form. Next, the portions of the wiring conductor layer 2 and the main conductor layer of the through conductor 7 are formed on the entire surface by electrolytic plating until the entire surface becomes substantially flat. Thereafter, the electrolytic plating film formed to an unnecessary thickness is removed to a predetermined thickness by a polishing method, a chemical etching method, or the like, whereby the wiring conductor layer 2 and the through conductor 7 having a desired wiring pattern shape can be processed. it can.
[0034]
The main conductor layer of the wiring conductor layer 2 formed on the surface of the insulating layer 1 which is the uppermost layer of the multilayer wiring board is made of a copper layer from the viewpoint of electrical characteristics and connection reliability. In this case, a nickel layer or a gold layer is preferably formed on the main conductor layer from the viewpoint of connection reliability and environmental resistance.
[0035]
Thus, according to the multilayer wiring board of the present invention, the semiconductor integrated circuit is formed in the wiring conductor layer 2 formed so as to be buried in the insulating layer 1 that is located in the uppermost layer or is the bottom surface of the recess formed in the multilayer wiring board. A semiconductor device is formed by mounting a circuit and electrically connecting the multilayer wiring board to an external electric circuit. At this time, since the uppermost surface of the multilayer wiring board of the present invention is a flat surface, a semiconductor integrated circuit having a narrow pitch connection terminal can be mounted without performing additional processing such as adjusting the height of the connecting solder. Can do.
[0036]
According to the multilayer wiring board of the present invention, the probe is arranged in contact with the wiring conductor layer 2 formed so as to be embedded in the insulating layer 1 positioned at the uppermost layer, and the multilayer wiring board is connected to the external electric circuit. By electrically and mechanically connecting to the semiconductor integrated circuit, it becomes a probe card for electrical inspection of a semiconductor integrated circuit or the like. At this time, since the uppermost surface of the multilayer wiring board of the present invention is a flat surface, stress concentration due to variations in probe height does not occur, measurement can be performed with stable contact resistance, and the probe can be used for a long time. Can be used.
[0037]
It should be noted that the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention. For example, in the above-described example, only the multilayer wiring portion in which the insulating layer 1 and the wiring conductor layer 2 are multilayered is formed to form a multilayer wiring substrate. For example, a ceramic substrate or a glass substrate is used as a supporting substrate for the multilayer wiring portion. It may be used.
[0038]
【The invention's effect】
As described above, according to the multilayer wiring board of the present invention, the insulating layer has the concave portion on the upper surface, and is laminated on the upper surface of the first insulating layer made of ceramic and the first insulating layer and has the concave portion. It has a through hole in the upper part, and consists of a second insulating layer made of organic resin and a third insulating layer made of organic resin laminated on the lower surface of the first insulating layer, and the lower surface of the wiring conductor layer is organic The resin penetrates through the second insulating layer made of resin and is embedded in the upper surface of the first insulating layer made of ceramic . As a result, part of the wiring conductor layer is embedded in the recess formed in the first insulating layer, so that the wiring conductor layer is disposed on the upper surface of the insulating layer made of ceramics as in the prior art. Thus, the protruding amount of the wiring conductor layer protruding from the insulating layer can be reduced . Further , since the lower surface of the wiring conductor layer is embedded in the recess formed in the first insulating layer made of ceramics, the wiring conductor layer can be firmly fixed to the insulating layer. Further, when the next insulating layer is laminated on the upper surface by the press working method, the first insulating layer made of ceramic is the third insulating layer made of organic resin even when the next insulating layer is heated and pressed. Since the wiring conductor layer is firmly fixed to the insulating layer, the third insulating layer protrudes from the lower insulating layer according to the shape of the first insulating layer. By deforming so as to wrap, the upper surface thereof can be processed according to the original shape of the first insulating layer. Thereby, the influence of the protrusion of the lower wiring conductor layer on the surface of the insulating layer formed on the uppermost surface of the multilayer wiring board can be suppressed, and the surface can be made flat.
[0040]
As a result, the wiring conductor layer formed on the flat top surface of the multilayer wiring board formed by laminating a plurality of insulating layers and wiring conductor layers in multiple layers and the connection portion of the semiconductor substrate can be arranged in parallel. Since it becomes easy, it becomes unnecessary to adjust the height of the solder for connecting the semiconductor substrate. As a result, the multilayer wiring board can cope with the narrow pitch of the wiring conductor layer with the flatness of the insulating layer formed on the uppermost surface of the multilayer wiring board being high.
[0041]
When the multilayer wiring board of the present invention is used as a probe card, a wiring conductor layer and a probe formed on the uppermost surface of the multilayer wiring board formed by laminating a plurality of insulating layers and wiring conductor layers. Variation in the height of the wiring, and the load applied to the probe during the inspection of the semiconductor integrated circuit can be prevented from being concentrated on a part of the upper surface of the wiring conductor layer. This can eliminate the problem of shortening the service life. Thereby, it becomes a multilayer wiring board excellent in electrical connectivity which can make contact resistance with a probe stable for a long time.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of a multilayer wiring board according to the present invention.
FIG. 2 is an enlarged cross-sectional view of a main part showing a state around a wiring conductor layer in an example of an embodiment of a multilayer wiring board of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Insulating layer 2 ... Wiring conductor layer 3 ... 1st insulating layer 4 ... 2nd insulating layer 5 ... 3rd insulating layer 6 ... Through-hole 7 ... through-conductor

Claims (2)

In this multilayer wiring board, an insulating layer and a wiring conductor layer are laminated in multiple layers, and the wiring conductor layers positioned above and below are connected to each other through a through-hole provided in the insulating layer therebetween. The insulating layer has a concave portion on the upper surface, is laminated on the upper surface of the first insulating layer made of ceramics, and has a through hole above the concave portion. And a third insulating layer made of organic resin laminated on the lower surface of the first insulating layer, and the lower surface of the wiring conductor layer is formed in the recess of the first insulating layer. A multilayer wiring board characterized by being embedded through the second insulating layer. 2. The multilayer wiring board according to claim 1, further comprising a diffusion barrier layer formed on the entire surface of the through hole and the recess provided in the insulating layer .

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