JP2540933B2 - Method of connecting semiconductor element to circuit board or carrier - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for connecting a semiconductor element in a semiconductor integrated circuit mainly composed of a semiconductor element to a circuit board or a carrier.

[Prior Art] Conventionally, when a semiconductor element such as an LSI and a carrier are connected to each other, a wire is used as shown in the sectional view of FIG. That is, conventionally, the semiconductor element and the circuit board or carrier have been connected using a wire bonding method in which both ends of the antenna are bonded.

However, with such a wire bonding method,
In particular, in integrated circuits that use high frequencies in the microwave band and above, it cannot be ignored because the inductance (L) of the wire portion becomes large, and it was necessary to incorporate it in the design, but actually expect that amount. Is difficult,
There was a problem of causing a loss or reducing a gain.

On the other hand, the microwave circuit substrate uses a structure of a microstrip line and a coplanar line, which are typical waveguides used in the microwave circuit substrate, because the manufacturing method is simple. Such a structure is manufactured using a photolithography technique.

[Problems to be Solved by the Invention] In order to solve the problems described above, the present invention provides
It is an object of the present invention to provide a method for connecting a semiconductor element to a circuit board or carrier with a thin film substrate on which a transmission path having the same impedance as a waveguide used for the circuit board or carrier is formed.

[Structure of the Invention] [Means for Solving Problems] The gist of the present invention is to provide a method of connecting a semiconductor 3 and a circuit board or a carrier 1 with a thickness of 30 to 120 μm.
Using the dielectric ceramic thin plate 5 of m as a connecting member,
A waveguide (conductor wiring portion) 2 whose impedance is used in the circuit board or carrier 1 to be connected
The impedance is equal to the impedance of the semiconductor element and the circuit board or the carrier.

The waveguide formed on the dielectric ceramic thin plate 5 is preferably a waveguide having a structure of any one of a microstrip line, a coplanar line and a grounded coplanar line. The dielectric ceramic thin plate 5 is preferably a dielectric ceramic material containing alumina as a main component. The metal conductor layer forming the waveguide is an Au layer having a thickness of 3 μm or more at the uppermost surface.
/ Pd / Ti, Au / Pd / Ni-Cr, Au-Ni-Cr / Ta-N, Au / Pd / Ta
It is preferable to have a three-layer structure selected from the group consisting of a three-layer structure of -N. Further, the dielectric ceramic thin plate 5, the semiconductor element 3 and the circuit board or carrier 1 are
It is preferable to connect via the signal line 8 or the ground terminal 13 using either solder or a conductive adhesive. It is preferable that the dielectric ceramic thin plate 5 using the microstrip line has a terminal 13 for ground connection on the surface on which the signal line 8 is present and has electrical continuity with the ground layer 9 on the opposite surface through the through hole 14. Is.

Further, it is preferable that the dielectric ceramic thin plate 5 using the grounded coplanar line has through holes 14 and that the ground layers 9 formed on both sides of the substrate are connected using the through holes. Is. The diameter of the through hole 14 is preferably 100 μm or less, and the thickness of the ceramic thin plate 5 is preferably 30 to 100 μm.

[Operation] According to the present invention, a thin film substrate on which a transmission line having an impedance equal to that of a waveguide used for a circuit substrate or a carrier is formed, that is, a circuit substrate for a microwave circuit has a similar structure with a thickness of 30 to 120 μm. On the dielectric ceramic substrate of, a waveguide of any one of a microstrip line, a coplanar line, and a grounded coplanar line is formed so as to have an impedance equal to that of the waveguide formed on the circuit board or the carrier to be connected. A thin film substrate is connected. By such a connection method, the characteristic deterioration due to the inductance of the aerial wiring portion in the conventional wire bonding method is improved.

The present invention has a thickness of 30 to 120 to achieve the above object.
A waveguide of any one of a microstrip line, a coplanar line, and a grounded coplanar line is formed on a dielectric ceramic thin plate of μm so as to have an impedance equal to that of a waveguide formed on a circuit board or a carrier to be connected. By connecting using a thin film substrate, we have developed a connection method that can improve the characteristic deterioration due to the inductance of the aerial wiring part in the conventional wire bonding method.

Also, the dielectric ceramic thin plate used has a thickness of 30 ~
It is preferable that the dielectric ceramic material is composed mainly of 120 μm alumina. A ceramic substrate having a thickness within this range is suitable for practical use of the ceramic substrate used.

The conductive thin film is an Au layer having a thickness of 3 μm or more on the uppermost surface, and Au / Pd / Ti, Au / Pd / Ni-Cr, Au-Ni-Cr / Ta-N, A
A material having a three-layer structure made of any material of u / Pd / Ta-N is preferable. That is, such a structure is suitable because it is a circuit for microwaves, the skin effect is taken into consideration, and the adhesive strength between the substrate and the conductor layer is secured. If the uppermost Au layer is less than 3 μm, the conductor loss increases,
This is inconvenient because the propagation loss increases.

The conductive layer as described above can be formed on the fired ceramics thin plate by a vapor deposition method, a spraying method, a sputtering method, or the like.

For example, it is possible to form a conductive thin film formed by various methods on both surfaces of a fired ceramics thin plate so as to have the structure of the present invention, by a method such as etching and photolithographic technique,
A conductor layer pattern can be obtained.

The method for producing the ceramic thin plate used in the present invention is not particularly limited, but there is a method for forming a ceramic green sheet and firing, and the others are not particularly limited.

Next, the method for connecting the semiconductor element and the circuit board or the carrier according to the present invention will be described with reference to specific examples, but the present invention is not limited to the description.

[Embodiment] The cross-sectional view of FIG. 2 shows a semiconductor device by the dielectric ceramic substrate 5 having the waveguide 8 (see FIG. 3) having the impedance of the circuit board 1 to be connected by the connection method of the present invention. 3 is a cross-sectional view of a connection part when the circuit board 3 and the circuit board 1 are connected by solder or a conductive adhesive 6.

The cross-sectional views in FIG. 3 are ceramic thin plates 5 for connection formed by (a) microstrip line type, (b) coplanar line type, and (c) grounded coplanar line type, respectively.
Is an example of. It is desirable to select these according to the shapes of the semiconductor element 3 to be connected, the circuit board, and the connecting terminal portion (conductor wiring terminal in FIG. 2) of the carrier 1. The material and thickness of the dielectric ceramics thin plate 5 are determined by the pitch of the semiconductor element 3 to be connected, the circuit board and the connection terminal portion 4 of the carrier 1 and the waveguide formed on the dielectric ceramics substrate 3. Although it is selected according to the type, most of the waveguides of the circuit board or carrier 1 are formed with impedance of 50Ω or 75Ω in any waveguide, so that the dielectric constant is about 10 and the loss is small. It is desirable to use a ceramic thin plate having a thickness of 30 to 120 μm, which is mainly composed of

(A) In the case of the microstrip line type, the ground 9 is provided on the surface of the dielectric ceramic thin plate 7 on which the signal line 8 is provided.
It is desirable to provide a terminal 13 for use with the through hole 14 and to ensure continuity of the ground layer 9 on the surface opposite to the ground terminal 13. At this time, it is more desirable to provide the ground terminal 13 at a position as far as possible from the signal line 8.

(B) In the case of the coplanar line type, as shown in the drawing, only on one surface of the dielectric ceramic thin plate 7 for circuit,
The conductor layer 8 for the signal line and the conductor layer 9 for the ground layer are formed in parallel at a predetermined interval.

(C) In the case of the grounded coplanar line type, the conductor layer 8 for the signal line and the conductive layer 9 for the ground layer are formed on one surface in parallel and at a predetermined interval. , The conductor layer 9 for the ground layer is formed on the other surface, and the through holes 14 are used to secure the conduction between the ground layers 9 formed on the surface of the circuit dielectric ceramic substrate 7. Is preferred.

The cross-sectional view of FIG. 4 shows the dielectric ceramic substrate 10 for a circuit.
And a semiconductor element (3 in FIG. 2), a circuit board or a carrier (2 in FIG. 2). In order to secure electrical continuity, the connecting portion is preferably connected with solder or a conductive adhesive 6. Also, the circuit board
The connection between 10 and the semiconductor element, the circuit board or the carrier is preferably made at least at two locations of the signal line 8 and the ground layer 9 or the ground terminal 13 (see FIG. 2) on the same surface as the surface on which the signal line is located. Is.

The waveguide on such a dielectric ceramic substrate is
It is formed by etching or lift-off using a photolithography technique.

The sectional views of FIGS. 5 (a), (b), (c), and (d) are
A method of forming a waveguide on the dielectric ceramic substrate 7 by using an etching method is sequentially shown.

First, as shown in the cross-sectional view of FIG. 5 (a), one surface (in the case of a coplanar line) or both surfaces (in the case of a microstrip line type, grounded coplanar line) of the dielectric ceramic thin plate 7 is vapor-deposited, The conductive thin film 11 is formed using a method such as a sputtering method or a plating method. At this time, the conductive thin film 11 is made of Au / Pd / Ti, whose uppermost layer is an Au layer having a thickness of 3 μm or more, in consideration of the large adhesive strength between the film 11 and the thin plate 7 and the skin effect. Au / Pd / Ni-Cr, Au
It is preferable to use a three-layer structure having either a structure of / Pd / Ta-N or Au / Ni-Cr / Ta-N.

Next, as shown in the cross-sectional view of FIG. 5B, a photoresist is used to form a resist layer 12 having a desired pattern. Then, as shown in the cross-sectional view of FIG. By etching the body layer 11 and then removing the resist layer as shown in the cross-sectional view of FIG. 5 (d), the desired waveguide 15 and the like can be formed.

The cross-sectional views of FIGS. 6 (a), (b), and (c) sequentially show a method of forming a waveguide on the dielectric ceramic thin plate 7 using the lift-off method. That is, a photoresist is used on one surface (in the case of a coplanar line) or both surfaces (in the case of a microstrip line or a grounded coplanar line) of the dielectric ceramic substrate 7 as shown in the sectional view of FIG. 6 (a). As a result, a resist layer 12 having the reverse pattern of the desired pattern is formed. Then, as shown in the sectional view of FIG. 6 (b), a conductor such as a conductor is formed on the surface of the circuit board 7 having the resist layer 12 of the reverse pattern by using a method such as a vapor deposition method, a sputtering method or a plating method. A thin film forming process is performed to form the conductor layer 11. Next, as shown in the cross-sectional view of FIG. 6C, the resist layer 12 is removed to remove the unnecessary portion of the metal conductor layer, and the desired waveguide 15 and the like can be formed.

In the above, in order to form a through hole in the circuit board, for example, for the structure shown in the sectional view of FIG. 3 (c), it is preferable to use a CO ₂ laser. At this time, it is desirable to form as many through holes 14 as possible on both sides of the substrate of the granded coplanar line structure to be formed, in a portion to be the ground layer, as close as possible to the signal line layer. However, in practice, it is necessary to secure the strength of the substrate, so the conductor layer (signal line layer)
It is preferable to form the conductor layer pattern at a distance of about 3 to 5 mm at a position apart from 8 to about 0.3 to 1.0 mm. If there is a large area ground layer, 3 mm
It is preferable to form one through hole at a rate of about one corner.

The conductor layer preferably has a three-layer structure in which a Ti layer of 0.3 μm, a Pd layer of 0.3 μm and an Au layer are formed on the surface of the circuit board by a sputtering method, and then an Au layer is further formed by a plating method. Is. The Au layer to be formed preferably has a thickness of 3 μm or more in consideration of the skin effect of the metal. The above-described method for forming a thin metal layer can be performed by sputtering or plating, but there is no difference between the two.
The total Au film thickness formed by both is preferably 3 μm or more. Further, by the above metal sputtering process, a metal thin film is formed also on the inner wall of the through hole, and the ground layer formed above and below and the conductor layer of the ground terminal can be electrically conducted through the through hole.

When the conductor layer 9 is close to the through hole 14 or when the plating method is used, after forming the conductor layer pattern 9, a protective layer for the conductor layer pattern is formed using photoresist. After that, it is preferable to perform sputtering.

EFFECTS OF THE INVENTION By the method of connecting a semiconductor element and a circuit board or carrier of the present invention, firstly, a connection method which eliminates the inductance component of the aerial wiring part in the conventional connection method by an antenna becomes easy, and the entire circuit is facilitated. It is possible to provide a thin film circuit board for microwaves that can greatly contribute to the stabilization of the characteristics of the above. Secondly, this connection method is not limited to the connection between the semiconductor element and the circuit board or the carrier, and the connection method between the circuit boards. The technical effects such as providing a method of connecting a semiconductor element and a circuit board or a carrier, which are expected to be effective, have been obtained.

[Brief description of drawings]

FIG. 1 is a sectional view of a connecting portion of a conventional circuit board. FIG. 2 is a sectional view showing a connection structure between a circuit board and a semiconductor element according to the present invention. 3 (a), (b), and (c) are sectional views showing the structure of the dielectric ceramic thin plate used in the present invention. FIG. 4 is a sectional view showing a structure for connecting the circuit board 1 and the semiconductor element 3 according to the present invention. FIGS. 5 (a), (b), (c), and (d) show a circuit signal line pattern by a photolithographic etching method for the dielectric ceramic thin plate having the conductor layer shown in FIG. 3 (c). 6A to 6C are cross-sectional views sequentially showing a method of forming a ground layer pattern. 6 (a), (b), and (c) are cross-sectional views sequentially showing a method of manufacturing the dielectric ceramic thin plate shown in FIG. 3 (c) by a lift-off method. [Explanation of Signs of Main Parts] 1 ... Ceramic circuit board 2 ... Conductor wiring part 3 ... Semiconductor element 4 ... Aerial wiring part 5 ... Dielectric ceramic thin plate used in the present invention 6 ... Solder or conductive Adhesive 7 …… Dielectric ceramics thin plate 8 …… Signal line conductor layer 9 …… Ground layer conductor layer 10 …… Circuit board 13 …… Ground terminal conductor layer 14 …… Through hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshinori Shinohara 2270 Yokose, Yokose-cho, Chichibu-gun, Saitama Mitsubishi Mining and Cement Co., Ltd. Ceramics Research Laboratory (56) Reference JP 62-193255 (JP, A) Flat 1-143502 (JP, A) JP 57-56774 (JP, B2)

Claims (8)

(57) [Claims] 1. A method of connecting a semiconductor element and a circuit board or carrier, wherein a dielectric ceramic thin plate having a thickness of 30 to 120 μm is used as a connecting member, and its impedance is used for the circuit board or carrier to be connected. A method for connecting a semiconductor element and a circuit board or a carrier, wherein the impedance is equal to the impedance of the waveguide (conductor wiring section) that is present. 2. The waveguide formed on the dielectric ceramic thin plate is a waveguide having any one of a microstrip line, a coplanar line and a grounded coplanar line. A method for connecting the semiconductor device according to the paragraph to a circuit board or a carrier. 3. The method for connecting a semiconductor element to a circuit board or a carrier according to claim 1, wherein the dielectric ceramic thin plate is a dielectric ceramic material containing alumina as a main component. 4. The metal conductor layer forming the waveguide is an Au layer having a thickness of 3 μm or more at the uppermost surface, and Au / Pd / Ti, Au / Pd /
The three-layer structure selected from the group consisting of the three-layer structure of Ni-Cr, Au / Ni-Cr / Ta-N and Au / Pd / Ta-N, according to claim 1. A method for connecting a semiconductor device and a circuit board or carrier. 5. The thin dielectric ceramic plate, the semiconductor element and the circuit board or carrier are connected to each other through a signal line or a ground terminal by using either solder or a conductive adhesive. Item 2. A method for connecting the semiconductor device according to item 1 to a circuit board or a carrier. 6. The thin conductor ceramic plate using the microstrip line has a terminal for ground connection on a surface on which a signal line is present, and has continuity with a ground layer on the opposite surface through a through hole. A method for connecting the semiconductor device according to claim 2 to a circuit board or a carrier. 7. A dielectric ceramic thin plate using the grounded coplanar line has through holes, and the through holes have electrical continuity between ground layers formed on both surfaces of the substrate. A method for connecting the semiconductor device according to claim 2 to a circuit board or a carrier. 8. The semiconductor device and the circuit board or carrier according to claim 7, wherein the through hole has a diameter of 100 μm or less and the ceramic thin plate has a thickness of 30 to 100 μm. How to connect.