JP2002151801A - Circuit board structure and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high-density three-dimensional mounting structure. SOLUTION: This three-dimensional mounting structure is formed, in such a way that recessed sections are formed on the surface of a silicon substrate through anisotropic etching or machining, and a semiconductor device and passive components are mounted on the substrate by arranging the device and parts in the recessed sections and forming circuit patterns above the device and components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a semiconductor device, a mounting structure of passive components, and a manufacturing method.

[0002]

2. Description of the Related Art A method of forming circuit wiring on a glass epoxy substrate and connecting mounted components, such as semiconductor devices, passive components such as capacitors and resistors, to the circuit substrate has been put to practical use. The connection structure of a semiconductor device according to this conventional technique will be described with reference to a sectional view showing a mounting step in FIG. 5 and a sectional view showing a step of a wire bonding method in FIG.

As shown in FIG. 5A, a glass epoxy substrate 19 is formed by patterning a copper thin film formed on a surface thereof, and a circuit wiring of a copper pattern 20 is formed at a height of 8 to 20 μm. Further, in order to prevent surface oxidation of the copper pattern 20, a structure in which a gold (Au) plating 21 having a thickness of about 0.01 to 5 μm is provided on the copper pattern 20 is general. Hereinafter, the copper pattern 20 on the glass epoxy substrate 19 and the Au plating 21 on the copper pattern 20 are collectively referred to as the circuit wiring 15.

[0005] As shown in FIG. 5 (b), a circuit wiring 15 on a glass epoxy substrate 19 and a solder bump electrode 14 formed by electroplating or screen printing on an electrode pad of a semiconductor device 12 are connected to a glass epoxy circuit. Mounted on a substrate. The composition of the solder is an alloy of tin and lead: tin: lead = 6: 4
The composition ratio is generally.

Next, as shown in FIG. 5C, the sealing resin 1 is inserted into a gap between the semiconductor device 12 and the glass epoxy substrate 19.
6, the gap is filled with a resin, and the sealing resin 16 is heated and cured to bond the semiconductor device 12 and the glass epoxy circuit board.

To mount the passive components 13 such as capacitors and resistors, first, as shown in FIG. 5B, solder 22 is applied on a circuit board by screen printing or dispensing, and the passive components 13 are arranged.

Then, as shown in FIG. 5C, a method of melting the solder 22 by reflow to fix the passive component 13 and electrically connect the same is general.

In mounting the semiconductor device 12, A
In some cases, the semiconductor device is mounted using a wire bonding method using a u-line or an aluminum line.

In this case, as shown in FIG. 6A, the semiconductor device 12 is placed on a glass epoxy substrate 19 with an adhesive 24.
Is fixed with the element surface facing up. The adhesive 24 used for fixing the semiconductor device 12 is electrically connected to the semiconductor device 12 and the circuit wiring 15 using an epoxy resin adhesive 24 containing Ag particles, and is connected to the ground. Is common. Since the adhesive 24 is mainly composed of an epoxy resin, the adhesive 24 is cured by heating for about 10 minutes to 1 hour in a furnace heated to 150 ° C. to 200 ° C.

Next, as shown in FIG. 6B, the electrodes of the semiconductor device 12 and the circuit wiring 15 formed on the glass epoxy substrate 19 are connected by using a wire 23 by a wire bonding method.

Next, as shown in FIG.
The three parts and the semiconductor device 12 are sealed with a molding agent 25 so as to completely cover them. The epoxy resin is used for the material of the molding agent 25.
Curing is carried out by heating in a furnace heated from 10 to 200 ° C. for 10 minutes to 1 hour.

[0012]

In the prior art, a glass epoxy board 19, a ceramic board, or the like is generally used as a mounting board for the semiconductor device 12 or the passive component 13, but these board materials are used. Due to poor dimensional accuracy such as heat resistance and deformation, it is difficult to form high-precision and high-density fine circuit wiring 15.

In addition, even if the circuit wiring is formed in multiple layers on the glass epoxy substrate 19 in order to perform high-density mounting and the mounting density on the surface of the substrate is increased, the area occupied by the mounted components of the semiconductor device 12 and the passive components 13 is increased. It is impossible to implement below.

Further, the difference between the thermal expansion coefficients of silicon as the material of the semiconductor device 12 and the glass epoxy substrate 19 is large,
If the temperature change of the environment used after mounting is large, thermal expansion and thermal contraction are repeated, and a phenomenon occurs in which the connection interface is distorted and the interface is peeled off, so that there is a problem that electrical conduction cannot be obtained.

An object of the present invention is to solve the above problems by using silicon of the same material as that of a semiconductor device as a circuit board material, and further forming a substrate concave portion and a fine circuit pattern on the silicon substrate, thereby forming an internal silicon substrate. Another object of the present invention is to provide a mounting structure having a high mounting density, a stable electric connection, and a high reliability, since a semiconductor device, passive components, and the like can be mounted.

[0016]

In order to achieve the above object, a semiconductor device and a passive component mounting structure according to the present invention employ the following configurations.

In a circuit board on which one or both of a semiconductor device and a mounted component of a passive component are mounted on a substrate, the substrate is a silicon substrate, and at least an arbitrary depth at which a mounted component can be embedded in a predetermined position. Substrate recesses are formed, and mounted components are mounted on circuit wiring formed on the mounting surface including the substrate recesses and the substrate projections formed therein. Characterized by having a tapered inclined surface at an angle of 、, after mounting components are disposed in the substrate recess, mounting the components to the second circuit wiring formed on the mounting surface flattened substrate sealing resin with sealing resin The feature is to implement.

Further, in a method of manufacturing a circuit board in which one or both of a semiconductor device and a mounted component of a passive component are mounted on a substrate, the substrate is formed at a predetermined position at an arbitrary depth using a silicon substrate as the substrate. Forming a concave portion, forming circuit wiring on a mounting surface including the substrate concave portion and the substrate convex portion, and mounting the mounted component at a predetermined position of the substrate concave portion and the substrate convex portion. After the step of mounting the mounted component at an arbitrary position between the substrate concave portion and the substrate convex portion, further flattening the substrate concave portion with a sealing resin, forming a second circuit wiring, and mounting the component at a predetermined position. The method is characterized in that the method includes a step of mounting a component, and the step of forming the concave portion of the substrate is performed by anisotropic etching or machining.

(Function) In the present invention, by using the same silicon substrate as that of the semiconductor device as the material of the circuit board, it is possible to form fine circuit wiring by the photolithography method and to process the substrate recess by anisotropic etching. A simple mounting structure can be formed.

Further, since the semiconductor device and the silicon substrate have the same thermal expansion, stable connection can be maintained even after mounting.

Further, by polishing the semiconductor device and the silicon substrate, a very thin mounting module can be manufactured.

Therefore, a thin, high-density three-dimensional mounting structure having higher connection reliability than the conventional structure can be obtained.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for mounting a semiconductor device according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a mounting structure of the present invention, FIG. 2 is a cross-sectional view of a circuit forming step of a silicon substrate, FIG. 3 is a cross-sectional view showing a mounting step on a silicon substrate 11, and FIG. FIG. Hereinafter, description will be made with reference to FIGS. 1, 2, 3, and 4.

The silicon substrate 11 used in the mounting structure of the present invention shown in FIG. 1 is formed by forming an indentation of an arbitrary depth in which a mounting component can be embedded in a substrate made of silicon by anisotropic etching. The circuit wiring is arranged. Further, a passive component 13 (not shown) such as a semiconductor device 12, a capacitor, and a resistor is connected to the substrate recess by a wire 22 using a solder 22 or a wire bonding method, and a second circuit wiring is further provided thereon. 1
5 'was formed, and further, mounted components of the semiconductor device 12 and the passive component 13 were arranged thereon, and each mounted component was electrically connected to form a circuit board.

FIG. 2 shows a silicon substrate 11 used as a circuit board.
Shows the processing steps. First, as shown in FIG. 2A, a silicon substrate 11 having a (100) crystal orientation and a SiO ₂ film 17 formed on the surface was used. That S
A photosensitive resist 18 was applied on the iO ₂ film 17, and a resist opening was formed at a position where the substrate recess 1 was formed by a photolithography method.

Next, as shown in FIG.
Dry etching with SiO _TwoThe film 17 is
Open in the shape of a turn. Furthermore, SiO_TwoOn the surface of membrane 17
The remaining resist is removed by an RIE method (reactor) in an oxygen atmosphere.
(Active ion etching method).

As shown in FIG. 2C, the substrate is immersed in 30% KOH heated to about 50 to 70 ° C. for 2 to 6 hours,
The silicon substrate 11 was etched using the O ₂ film 17 as a mask.

Further, as shown in FIG.
The iO ₂ film 17 is removed by RIE using Ar gas, and the silicon substrate 11 having the substrate concave portion 1 and the substrate convex portion 2 is removed.
Was formed.

Finally, as shown in FIG. 2E, an SiO ₂ film 17 is formed on the entire surface as an insulating layer on the surface, and aluminum (Al), copper (C) is formed thereon by sputtering or vapor deposition.
u) or gold (Au) to form a conductive film, and the circuit wiring 15 was formed by photolithography.

In the case of forming a multilayer circuit wiring, an insulating film such as polyimide or SiN may be formed, and photolithography may be repeated to form the circuit wiring 15.

Next, as shown in FIG. 3A, the semiconductor device 12 is
And a passive component 13 (not shown) such as a capacitor resistor.

The semiconductor device 12 and the circuit wiring 15 were connected by a wire bonding method or a flip chip method using a solder or a conductive adhesive according to a mounted component. In the wire bonding method, connection was made by welding an Au wire or an aluminum wire having a diameter of about 20 μm to 50 μm to the electrode portion of the semiconductor device 12 and the circuit wiring 15 of the silicon substrate 11 by ultrasonic waves and pressure.

In the case of mounting using a flip-chip method using solder, a semiconductor device in which a bump electrode 14 of a solder material of tin: lead = 6: 4 is formed on an electrode portion by plating or screen printing. 12 was arranged and heated in a heating furnace to melt and join the solder. When the composition of the solder is tin: lead = 6: 4, the melting temperature is 183 ° C.
The solder was melted by heating from about 83 ° C. to about 240 ° C.

When a conductive adhesive is used, the semiconductor device 1
A gold projecting electrode 14 is formed on the electrode portion 2 by plating.
A conductive adhesive in which Ag particles are mixed into an epoxy resin is applied on the protruding electrodes 14, and the semiconductor device 12 in which the conductive adhesive is applied on the protruding electrodes 14 is arranged on the circuit wiring 15,
10 minutes to 1 in a furnace heated from 100 ° C to 170 ° C
The conductive adhesive was cured by heating for a period of time.

Passive components 13 such as capacitors and resistors
Is to apply the solder 22 on the circuit wiring 15 by screen printing or dispensing, dispose the passive component 13 thereon, and perform fusion bonding by heating.

Next, as shown in FIG.
A sealing resin 16 made of an insulating resin is injected into and sealed.
The surface was further polished to flatten the substrate recess 1. The sealing resin 16 to be injected into the substrate concave portion 1 may be any resin as long as it is an insulating resin. In the present embodiment, flattening was performed using an epoxy resin. Thereafter, the mixture was put into a furnace heated from 100 ° C. to 170 ° C. for 10 minutes to 30 minutes to cure the sealing resin 16.

Further, as shown in FIG.
A second circuit wiring 15 'is formed again by the photolithography method, and mounted components such as the semiconductor device 12 and passive components 13 such as a capacitor and a resistor are mounted on the second circuit wiring 15' by a flip chip method, a wire bonding method, or the like. Alternatively, it was mounted by a solder printing method. The mounting component may be placed on the upper part (the surface of the sealing resin) of the lower mounting component, or the mounting component may be mounted on the protrusion of the substrate.

When there are a plurality of semiconductor devices 12 and passive components 13 mounted on the silicon substrate 11, the above mounting process is repeated, and a plurality of semiconductor devices 12 and passive components 13 are mounted.

In the above embodiment, the method using anisotropic etching for forming the substrate concave portion 1 has been described. However, the substrate concave portion 1 can be formed by machining such as cutting to form the circuit structure. .

In the present invention, since the semiconductor device 12 and the silicon substrate 11 are made of the same material and have the same physical characteristics such as a coefficient of thermal expansion, the bonding is performed even if a temperature change in the use environment after mounting occurs. Distortion due to the difference in thermal expansion did not easily occur at the interface, and a stable connection could be maintained.

Further, since the semiconductor device 12 and the substrate are made of the same silicon material, there is no difference in thermal expansion between the semiconductor device 12 and the silicon substrate 11 even when a reliability test such as a thermal shock test is performed. Thus, a stable connection could be obtained without any distortion at the joint.

Since the silicon substrate 11 has low thermal expansion and good flatness, pattern formation by photolithography could be performed with high precision. Specifically, it has been found that it is also possible to form the circuit wiring 15 having a pitch of 10 μm.

Further, it is possible to reduce the thickness by polishing the silicon substrate 11 and to reduce the thickness of the substrate to 100 μm.
And then the semiconductor device 12 is also polished to 10
By setting the thickness to about 0 μm, a thin circuit board structure having a total thickness of about 0.3 mm can be manufactured even when the thickness of the mounting portion and the wiring layer is taken into account.

The silicon substrate 11 having the crystal orientation (100) was etched with KOH to form the concave portions 1 and the convex portions 2 of the substrate. As shown in FIG. 4, the etching proceeds rapidly at the bottom surface (100), and (11)
Since the (1) plane has a lower etching rate, a larger number of (111) crystal orientation planes remain than the (100) plane.
1) It was possible to form the substrate concave portion 1 whose surface was a tapered inclined surface having an arbitrary angle.

Therefore, even when the circuit wiring 15 is formed by a sputtering method or a vapor deposition method, the step coverage is good, and disconnection or the like is unlikely to occur when the circuit wiring film is formed.

[0046]

As is clear from the above description, according to the present invention, by mounting a semiconductor device on a silicon substrate, more stable and fine connection can be achieved, and furthermore, it is possible to work ultra-thin. Thus, a highly reliable small and thin three-dimensional mounting circuit using fine wiring could be obtained.

Although the two-stage stacked type high-density circuit board structure has been described with reference to FIG. 3B, a deeper substrate recess 1 is formed in the silicon substrate 11, and the three-stage and four-stage stacked structures are formed. It goes without saying that a circuit board structure may be used.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a mounting structure according to the present invention.

FIG. 2 is a sectional view of a processing step of the silicon substrate of the present invention.

FIG. 3 is a sectional view of a mounting process according to the present invention.

FIG. 4 is an explanatory view of anisotropic etching of the present invention.

FIG. 5 is a cross-sectional view of a mounting process according to the related art.

FIG. 6 is a sectional view of a mounting process by a wire bonding method according to a conventional technique.

[Explanation of symbols]

1 substrate recess 2 substrate protrusions 11 a silicon substrate 12 semiconductor device 13 passive component 14 projecting electrode 15 circuit wiring 15 'the second circuit interconnection 16 sealing resin 17 SiO ₂ film 18 photoresist 19 glass epoxy substrate 20 copper pattern 21 gilding 22 Solder 23 Wire 24 Adhesive 25 Molding agent

Claims (7)

[Claims] 1. A circuit board having one or both of a semiconductor device and a mounted component of a passive component mounted on the substrate,
The substrate is a silicon substrate, a substrate recess of an arbitrary depth capable of embedding at least a mounting component is formed at a predetermined position, and a circuit wiring formed on a mounting surface including the substrate recess and the substrate protrusion. A circuit board structure on which the mounting component is mounted. 2. The circuit board structure according to claim 1, wherein said substrate recess has a tapered inclined surface having an arbitrary angle. 3. A mounting component is mounted on a second circuit wiring formed on a mounting surface in which the substrate recess is flattened with a sealing resin after the mounting component is arranged in the substrate recess. The circuit board structure according to claim 1. 4. A method of manufacturing a circuit board in which one or both of a semiconductor device and a mounted component of a passive component are mounted on a substrate, wherein the substrate is provided at a predetermined position at an arbitrary depth by using a silicon substrate as the substrate. Forming a recess, and forming circuit wiring on a mounting surface including the substrate recess and the substrate projection,
A method of manufacturing a circuit board structure, comprising a step of mounting the mounted component at predetermined positions of a substrate concave portion and a substrate convex portion. 5. After the step of mounting a mounting component at an arbitrary position between the substrate concave portion and the substrate convex portion, further flattening the substrate concave portion with a sealing resin, and forming a second circuit wiring; The method for manufacturing a circuit board structure according to claim 4, further comprising a step of mounting a mounting component at a predetermined position. 6. The method according to claim 4, wherein the step of forming the substrate recess is performed by anisotropic etching. 7. The method of manufacturing a circuit board structure according to claim 4, wherein the step of forming the substrate recess is performed by machining.