JP3203731B2 - Semiconductor element substrate and mounting method, substrate with columnar terminals and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant and shock-resistant semiconductor element mounting board and method for bonding a semiconductor element to a ceramic substrate by bump bonding.

[0002]

2. Description of the Related Art Conventionally, as a method of electrically connecting a bare semiconductor element to a substrate on which a conductor pattern is formed, a projecting contact is formed on an electrode pad of the semiconductor element by a plating method, and this projecting contact is formed. It was common to connect substrates.

Also, US Pat. No. 4,661,192 describes a method for simply connecting a semiconductor element to a substrate by face-down using a conductive adhesive.

[0004] A conventional method for connecting semiconductor devices will be described below with reference to the drawings. FIGS. 6A to 6D show a connection process of a conventional semiconductor element. FIG. 6A shows a step of forming a projecting contact on the semiconductor element. As shown in the figure, a metal ball 21 is melted and connected to an electrode pad formed on a semiconductor element 15. The preparation of the metal ball 21
The metal wire 19 supported through the capillary is heated and melted by a hydrogen flame torch to form a ball 18, and the capillary 17 is pressed against the electrode pad 16 to fix the ball 18 to the electrode pad 16. After that, the metal wire 19 is pulled and cut to form a projecting contact made of the metal ball 21 and the remaining metal wire 22 on the electrode pad 16.

Next, as shown in FIG. 6B, a flattened ball 23 is obtained by pressing the semiconductor element 15 having the metal ball 22 fixed thereon against a base material 24 having a flat surface formed thereon.

Further, as shown in FIG. 6C, the semiconductor element 15 to which the flattened balls 23 are connected is brought into contact with a conductive adhesive 25 applied on a supporting base material 26 to be flattened. The conductive adhesive is transferred only on the ball 23.

As described above, the semiconductor element 15 in which the conductive adhesive 25 is formed on the flattened ball 23 on the electrode pad 16 is connected to the conductor pattern 27 on the substrate 28 as shown in FIG. The electrical connection is made by positioning and fixing in position.

[0008]

However, in the conventional method for electrically connecting a semiconductor element to a substrate as described above, a semiconductor element having a different coefficient of thermal expansion is very closely connected to a substrate. There is a problem that the connection part is broken by the generated stress.

In addition, since the bonding pitch width of the semiconductor element is regulated by the shape of the ball fixed to the electrode pad and the dimensions of the capillary, there is a problem that it is difficult to finely join the semiconductor element to the substrate.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and a semiconductor device mounting substrate and a mounting method capable of forming a columnar bump on a substrate and electrically connecting the semiconductor device to the columnar bump with high reliability. The purpose is to provide.

[0011]

In order to solve the above-mentioned problems, the present invention comprises a substrate on which a semiconductor element is mounted, and a column-shaped conductor bump protruding upward with respect to the substrate surface, wherein the column-shaped conductor bump is provided at the front. An electrode pad of a semiconductor element is directly connected to an inner conductor pattern inside the substrate, and is bonded to the columnar conductor bump.

A step of forming a board-constituting sheet and a sheet for forming a bump; a step of forming a hole in each of the sheets and a step of filling the holes with a conductive paste; A step of sequentially laminating a plurality of substrate constituent sheets as a lower layer, a step of firing the laminated multilayer sheet and removing the uppermost layer, and mounting a semiconductor element on the pillar-shaped bump formed at that time by a face-down bonding method And a step of mounting the semiconductor element.

The bump forming sheet has a higher sintering temperature than the substrate forming sheet, and is sintered at a temperature intermediate between the sintering temperature of the bump forming sheet and the sintering temperature of the substrate forming sheet. In this case, the sheet for forming the bump is removed. Further, a substrate for mounting a semiconductor device, wherein a pole terminals protruding upward with respect to the substrate surface, the columnar conductor bump is columnar terminal-provided substrate which is directly connected to the pre-Symbol substrate inside of the inner layer conductor pattern. Further, the columnar terminal is a multi-terminal pin grid array. Further, a semiconductor element is mounted on a surface opposite to a surface on which the columnar terminals are provided, and an electrode pad of the semiconductor element and the columnar terminals are electrically connected.
A step of forming a board-constituting sheet and a sheet for forming a pillar-shaped terminal; a step of perforating both sheets and filling the hole with a conductive paste; And a step of sequentially laminating a plurality of substrate constituent sheets as lower layers, and a step of firing the laminated multilayer sheet to remove the uppermost layer. In addition, the columnar terminal forming sheet has a higher sintering temperature than the substrate forming sheet, and is sintered at a temperature intermediate between the sintering temperature of the columnar terminal forming sheet and the sintering temperature of the substrate forming sheet. Is removed.

[0014]

According to the present invention, the columnar bumps are used to buffer the shear stress generated by heat even when the semiconductor element having a different coefficient of thermal expansion is connected to the ceramic substrate by forming the bumps into a columnar shape. Thus, a semiconductor device mounting board and a mounting method which are very stable against ambient temperature changes and have high reliability can be realized.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a semiconductor device according to an embodiment of the present invention;

FIGS. 1A to 1G show a columnar bump forming step of the first embodiment. As shown in FIGS. 1A and 1B, a substrate forming sheet 1 and a bump forming sheet 2 are formed on a polymer sheet 3 by a sheet forming process. The material of the substrate forming sheet 1 is a low-temperature sintering material in which glass is contained in alumina, and the material of the bump forming sheet 2 is a material having a sintering temperature higher than that of the substrate forming sheet 1, for example, pure alumina, boron nitride, Use magnesium oxide or the like. The sheets thus formed are perforated as shown in FIGS. 1C and 1D, and the holes are filled with the conductive paste 4. Copper oxide is generally used as the main material of the conductor paste 4, but other materials such as gold and silver may be used. Next, as shown in FIG. 1E, the bump forming sheet 2 is the uppermost layer, and a plurality of substrate constituent sheets 1 are formed.
Are sequentially laminated as a lower layer. At this time, the inner layer conductor pattern 5 is formed between the substrate sheets. This laminated sheet is fired at a temperature at which only the substrate forming sheet 1 made of a low-temperature sintering material is sintered, and only the uppermost layer made of the bump forming sheet 2 that cannot be sintered at this temperature is removed. Through the above steps, the columnar bumps 7 are formed as shown in FIG.

Further, as shown in FIG. 1 (g), the semiconductor element 6 having the solder bumps 9 on the electrode pads 8 is face-down on the columnar bumps and soldered by passing through a heating furnace to perform electrical connection. Make a connection.

FIG. 2 shows a columnar bump configuration in a process of forming a mounting board for a semiconductor element. As shown in the figure, the feature is that the bumps 7 are formed in a column shape higher than the upper surface of the substrate 10. FIG. 3 shows a configuration in which a semiconductor element is mounted on a columnar bump. As shown in the drawing, the semiconductor element 6 and the substrate 1 are joined via a columnar bump 7.

As a second embodiment, a method of forming terminals of a pin grid array will be described below with reference to the drawings.

FIGS. 4A to 4G show a step of forming a pin grid array terminal. As shown in the figure, the columnar terminals 11 are formed in the same manner as in the columnar bump forming step of the first embodiment. In this case, the columnar terminals 11 are formed on four sides of a rectangular substrate,
An electrode 12 that is electrically connected to each of the columnar terminals 11 is formed on a surface opposite to the surface having the columnar terminals 11. Thereafter, as shown in FIG. 4 (g), the semiconductor element 6 is mounted on the surface opposite to the surface on which the columnar terminals 11 are provided, and the electrode pads 8 of the semiconductor element 6 and the conductor electrodes 12 on the substrate are bonded by wire bonding. It is electrically connected by the gold wire 13. FIG.
(A) to (c) show the configuration of the pin grid array main body. It is characterized in that the columnar terminals 11 electrically connected to the semiconductor element 7 are directly connected from the inside of the pin grid array main body 14. FIG. 5B shows a 4-terminal pin grid array.
FIG. 5C shows the configuration of a multi-terminal pin grid array.

According to the above configuration, mounting with high resistance to thermal shock and high bump pitch accuracy is possible.

[0022]

As is apparent from the above description of the embodiments, according to the semiconductor device mounting board and the mounting method of the present invention, the bumps are formed in a columnar shape so that the semiconductor elements and the boards having different thermal expansion coefficients can be separated. Even when connected, the columnar bumps absorb the strain and become very stable against shear stress due to heat. In addition, by changing the conventional ball-shaped bumps formed on the semiconductor element side to the columnar bumps formed on the substrate side, the pitch accuracy of the bumps is improved, and the fine bonding of the semiconductor element to the mounting substrate becomes possible.

Further, in the columnar terminal of the pin grid array according to the present invention, the pin pitch accuracy is determined by the accuracy of the hole forming position and the hole diameter in the process. A pitch pin can be formed.

Such a mounting substrate for a semiconductor element and a columnar terminal of a pin grid array can be easily realized with conventional equipment for manufacturing a ceramic multilayer substrate, and require no new equipment. It is.

[Brief description of the drawings]

FIGS. 1A to 1G are cross-sectional views showing a columnar bump forming step and a semiconductor mounting step according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a configuration of a columnar bump on the substrate.

FIG. 3 is a cross-sectional view illustrating a configuration in which the semiconductor element is mounted on a substrate.

FIGS. 4A to 4G are cross-sectional views illustrating a step of forming a columnar terminal of the pin grid array according to the second embodiment.

5A is a cross-sectional view showing the configuration of the columnar terminals of the four-terminal pin grid array. FIG. 5B is a side view of the four-terminal pin grid array. FIG. 5C is a perspective view of the multi-terminal pin grid array.

6 (a) to 6 (d) are cross-sectional views showing steps of mounting a conventional semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate constitution sheet 2 Bump forming sheet 3 Polymer sheet 4, 5 Conductive paste 6 Semiconductor element 7 Columnar bump 8 Electrode pad 9 Solder bump 10 Substrate 11 Columnar terminal 12 Conductor electrode 13 Gold wire 14 Pin grid array main body

Claims (8)

(57) [Claims] A substrate for mounting the claim 1 a semiconductor device, and a columnar conductor bumps projecting upward with respect to the substrate surface, the columnar conductor bump is directly connected to the previous SL substrate inside of the inner layer conductor pattern, the columnar A semiconductor element mounting substrate formed by bonding electrode pads of a semiconductor element on conductive bumps. 2. A step of forming a substrate forming sheet and a sheet for forming a bump, a step of forming holes in both sheets and filling the holes with a conductive paste, and a step of forming a sheet for forming a bump among the two types of sheets. A step of sequentially laminating a plurality of substrate constituent sheets as an upper layer and a lower layer, a step of firing the laminated multilayer sheet and removing an uppermost layer, and a step of mounting a semiconductor element on a columnar bump formed by removing the uppermost layer. A semiconductor element mounting method including a step of mounting by a down bonding method. 3. The bump forming sheet has a higher sintering temperature than the substrate forming sheet, and is sintered at a temperature intermediate between the sintering temperature of the bump forming sheet and the sintering temperature of the substrate forming sheet.
3. The method according to claim 2, wherein the unsintered bump forming sheet is removed. 4. A substrate for mounting a semiconductor element, and a columnar pin that protrudes upwardly with respect to the substrate surface, the columnar conductor bump before Symbol pole terminals attached substrate directly connected with the inner layer conductor pattern in the substrate . 5. The substrate with columnar terminals according to claim 4, wherein the columnar terminals are a multi-terminal pin grid array. 6. The substrate with columnar terminals according to claim 5, wherein a semiconductor element is mounted on a surface opposite to a surface on which the columnar terminals are provided, and an electrode pad of the semiconductor element is electrically connected to the columnar terminals. 7. A step of forming a board-constituting sheet and a sheet for forming a pillar-shaped terminal, a step of making holes in both sheets and filling the hole with a conductive paste, and a sheet for forming a pillar-shaped terminal among the two types of sheets. A step of sequentially laminating a plurality of substrate constituent sheets as a lower layer and a step of firing the laminated multilayer sheet to remove the uppermost layer, and a step of removing the uppermost layer. 8. The columnar terminal forming sheet has a higher sintering temperature than the substrate forming sheet, and is sintered at a temperature intermediate between the sintering temperature of the columnar terminal forming sheet and the sintering temperature of the substrate forming sheet; The unsintered columnar terminal forming sheet is removed.
A method for producing a substrate with columnar terminals according to the above.