JPH0410649A - Manufacture of semiconductor substrate for three-dimensional packaging - Google Patents

Abstract

PURPOSE:To stick to laminate many semiconductor substrates directly by forming pads, which are connected to each other through holes, on both faces of the semiconductor substrates. CONSTITUTION:Circuits 1a and electrode pads 1b are formed on one face of an Si substrate 1. The face, having the circuits 1a, of the Si substrate 1 is attached to an SiO2 substrate 11 as a supporting substrate and then the Si substrate 1 is abraded to a thickness of about several micrometers. Through holes 2 are made by reactive ion etching(RIE), where the electrode pads 1b are formed. The through holes are filled with an insulator 3 such as SiO2 by the CVD method, and the insulator 3 is laminated on the abraded face of the Si substrate 1. Smaller through holes 4 than the through holes 2 are made in the insulator 3 in the through holes 2 by windowing and a film of a conductor such as Al is formed by sputtering or deposition and patterned to make connection pads 5 connected to the electrode pads 1b through the through holes 4.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for manufacturing a semiconductor circuit board for three-dimensional high-density packaging.

<Prior Art> In order to obtain a high-density three-dimensional IC, it is necessary to stack semiconductor substrates on which circuits are formed in multiple layers and electrically connect them to each other.

Conventionally, techniques for obtaining three-dimensional ICs include a method of bonding between input and output of each IC, a method of bonding at the element level, a monolithic method, and the like. Among these methods, the bonding method between input and output has advantages such as fewer technical problems, easy production, high yield, and the ability to stack ICs with various functions.

<Problem to be solved by the invention> By the way, in the above-mentioned bonding method between input and output, it is necessary to take a large area for the pad electrode, making it difficult to increase the degree of integration. The problem remains that the chip cooling effect is low because of the gaps.

<Means for Solving the Problems> In order to solve the above conventional problems, in the present invention, as shown in FIG. 1 corresponding to the embodiment, a circuit 1a and an electrode pad 1b are formed on the negative side. After drilling a through hole 4 in the semiconductor substrate 1 to expose the electrode pad 1b on the other surface of the semiconductor substrate 1, a connection pad is formed on the other surface of the semiconductor substrate 1 to be electrically connected to the electrode pad 1b through the through hole 4. 5 is formed.

<Function> By forming pads 1b and 5 that are electrically connected to each other through through holes 4 on both sides of semiconductor substrate 1, it becomes possible to directly bond each substrate 1 together when stacking semiconductor substrates 1 in multiple layers. .

<Example> Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a process explanatory diagram of an embodiment of the present invention.

First, as shown in (a), a Si substrate 1 on which a circuit 1a and an electrode pad 1b are formed on the negative side is bonded with its circuit 1a side side to an SiO7 substrate 11 serving as a supporting substrate. In this state, the Si substrate 1 is polished to a thickness of approximately several μm.

Next, after a through hole 2 is formed at the formation position of the electrode pad 1b by RIE (reactive ion etching) method or the like (C), an insulator 3 such as S i 0, 2 is formed in the through hole by a CVD method. 2 and laminated on the polished surface of the Si substrate 1 (d).

Next, the insulator 3 filled in the through hole 2 is opened by RIE method or the like to form a through hole 4 smaller than the through hole 2 (e). After forming a film of a conductive material such as A1 by sputtering or vapor deposition, the film is patterned to form a connection pad 5 that is electrically connected to the electrode pad 1b through the through hole 4, as shown in FIG. get. By the above procedure, the thickness is several μm.
S with pads 1a and 5 formed on both sides.
i A semiconductor circuit board can be obtained.

The semiconductor circuit board as described above is made three-dimensional by a commonly used IC bonding method, and the method will be described below. FIG. 2 is a diagram explaining the procedure.

First, vertical interconnections 6 for bonding are formed on the connection pads 5 of the semiconductor circuit board obtained in the process shown in FIG. 1 (a). Note that 7 is an insulating film. Next, as shown in (c), the surface is flattened using polyimide 8.

Next, prepare two circuit boards obtained in steps (a) and (b) above, and combine these two circuit boards with (C
), the two are connected by thermocompression bonding with the vertical wires 6 facing each other and in contact with each other. Next, by peeling off one of the SiO□ substrates 11 as supporting substrates, a laminated structure as shown in (d) is obtained. By sequentially repeating the above steps (a) to (d), a structure in which semiconductor circuits are stacked in multiple layers, that is, a three-dimensional IC can be realized. By creating, for example, an amplifier circuit for a sensor using such a three-dimensional IC, a compact sensor unit integrated with a sensor chip can be constructed.

According to the embodiment of the present invention described above, after the through hole 2 drilled in the semiconductor substrate 1 is filled with the insulator 3, the through hole 4, which is smaller than the through hole 2, is formed in the insulator 3. The conductive material filled inside the through hole 4 in the process is electrically insulated from the semiconductor substrate 1, thereby preventing the influence of signal input/output from reaching the semiconductor substrate 1. .

<Effects of the Invention> As explained above, according to the present invention, pads that are electrically connected to each other through through holes formed in the substrate itself are formed on both sides of the semiconductor substrate, so that any number of semiconductor substrates can be multilayered. This makes it possible to easily realize large-scale three-dimensional ICs. Furthermore, since each semiconductor substrate can be directly bonded together, the pad area can be reduced, a high-density three-dimensional IC can be obtained, and the cooling efficiency of the semiconductor substrate can also be improved.

[Brief explanation of the drawing]

FIG. 1 is a process explanatory diagram of an embodiment of the present invention, and FIG. 2 is a diagram illustrating an example of a procedure for constructing a three-dimensional IC using a semiconductor circuit board obtained by an embodiment of the present invention. 1...St substrate 1a...Circuit 1b...Electrode pad 2...Through hole, insulator, through hole, connection pad, vertical wiring, insulating film, polyimide

Claims (1)

[Claims] A through hole is formed in a semiconductor substrate on which a circuit and an electrode pad are formed on one side, and the electrode pad is exposed on the other side of the semiconductor substrate. A method for manufacturing a semiconductor substrate for three-dimensional mounting, which forms a connection pad that is conductive to a pad.