JPH04342132A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the etching remaining after the boring etching of an oxide film or the etching inferiority such as etching over, etc., by dividing the scribe line for judging the end point of the etching of the oxide film into many pieces. CONSTITUTION:Contact holes 8B, 8C, 11B, 12B, 14B, 15B, and 16B for taking out electrodes are opened in the specified positions of the respective process oxide films 10, 13, and 17 of a high-concentration p-type conductive layer 8, a p-type conductive layers 11 and 12, and n-type conductive layers 14-16 by photolithography technology. At this time, the end point of etching can be judged by the water break from the surface of a substrate together with the etching end of the whole 9A-9C of a scribe line 9 being divided. Hereby, the etching remaining and the etching inferiority such as etching over, etc., in the boring etching of the oxide films 10, 13, and 17 can be reduced.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device made of silicon and silicon compounds, and particularly relates to etching of a silicon oxide film.

0002

2. Description of the Related Art A semiconductor device using a semiconductor substrate includes, for example, an N-type conductive layer, a P-type conductive layer, wiring, bonding pads, and a passivation film for protecting elements on a silicon substrate. This semiconductor device is used in a variety of applications as a semiconductor device having various functions depending on the semiconductor substrate used, the combination of N-type conductive layers and P-type conductive layers, and the routing of wiring. For example, a bipolar IC using a silicon substrate can be formed by applying the configuration and manufacturing process shown in FIG. First, as shown in FIG. 2A, an N-type conductive layer 2 is formed on a part of a P-type silicon substrate 1, and an N-type silicon layer 3 is deposited thereon. An oxide film 4 is formed on the surface 3A of the N-type silicon layer, holes are made at predetermined positions in the oxide film 4 by photolithography, and a P-type conductive layer 5 is formed by diffusion technology to serve as an element isolation layer. Next, the surface oxide film 4 and the process oxide film 6 at the time of forming the element isolation layer are removed, and a new surface oxide film 7 is formed.
), holes 8A are made at predetermined positions using photolithography technology. The etching end point of the surface oxide film 7 at this time can be determined by the water draining from the substrate surface at the same time as the etching of the scribe line 9 is completed. Then, a high concentration P-type conductive layer 8 is formed in this hole 8A using a diffusion technique. This heavily doped P-type conductive layer 8 becomes the emitter and collector of the lateral type PNP transistor. Next, as shown in FIG. 2C, holes 11A and 12A are formed at predetermined positions in the process oxide film 10 of the oxide film 7 and the heavily doped P-type conductive layer 8 by photolithography. The end point of etching the oxide film at this time is determined by water draining from the substrate surface when the etching of the scribe line 9 is completed, as in the hole etching of the high concentration P-type conductive layer 8. Because there is a difference in the thickness of the oxide film between the two parts, etching residue may occur. Next, P-type conductive layers 11 and 12 are formed in the hole portions 11A and 12A by diffusion technology, and NPN
Use as the base and resistor of the transistor. Next, Figure 2 (D
), holes 14A and 15A are made by photolithography at predetermined positions in the process oxide films 10 and 13 during the formation of the oxide film 7, the highly concentrated P-type conductive layer, and the P-type conductive layer. At this time, the etching of the oxide film is only the process oxide film 13 when forming the P-type conductive layer for the base in the hole 14A, but in the hole 15A, the etching is triple-layered with the surface oxide film 7 and the process oxide films 10 and 13. Therefore, the completion of etching cannot be determined at the scribe line portion 9 as in the previous process. Therefore, the etching end point of this step is determined by providing an etching monitor (not shown) in the portion where the surface oxide film 7 and the process oxide films 10 and 13 overlap. N-type conductive layers 14, 15, 16 and a process oxide film 17 at this time are formed in the hole portions 14A, 15A by diffusion technology to form the emitter 14 and collector 15 of the NPN transistor and the base 16 of the PNP transistor. Furthermore, as shown in FIG.
Contact holes 8B, 8C, 11B, 1 for taking out electrodes are formed at predetermined positions in each of the process oxide films 10, 13 of 6.
2B, 12C, 14B, 15B, and 16B are opened using photolithography technology. The end point of the etching at this time is determined by etching the hole for the N-type conductive layer.
Since the scribe line part was not etched, the process oxide films 13 and 17 are double in the scribe line part, and the process oxide film 1 of the scribe line part 9 is
This is possible when water drains from the substrate surface upon completion of etching steps 3 and 16. Although not shown, the contact holes are further wired in a predetermined pattern and protected with a passivation film for protecting the device. Thereafter, the bipolar IC is completed by cutting it to a predetermined size, fixing it in a package, connecting the bonding pad and external terminal by bonding, and sealing it with resin or glass.

0003

[Problems to be Solved by the Invention] The etching end point of the conventional oxide film and process oxide film mentioned above is mainly determined by water draining from the substrate surface when the oxide film in the scribe line area is etched, so-called surface water draining. are doing. However, in the conventional technology, the scribe line for determining the etching end point is the same, so when the process oxide film is multilayered, there is a difference between the thickness of the oxide film at the scribe line and the thickness of the oxide film in which the hole is actually made. As a result, an error occurs in determining the etching end point, and etching remains. An object of the present invention is to enable the end point of etching to occur at a portion having the same thickness as the oxide film to be actually etched.

0004

[Means for Solving the Problems] In order to achieve the above object, the present invention divides the scribe line portion for determining the etching end point of the oxide film into multiple lines instead of the conventional one.
A different scribe line for determining the end point of oxide film etching can be used for each process.

[0005]

[Operation] According to the above means, the thickness of the oxide film at the part where the hole is made and the thickness of the oxide film used to determine the etching end point can be made the same, so that etching residues and over-etching in the hole-making etching of the oxide film can be avoided. Defects can be reduced.

[0006]

[Example] Hereinafter, in the configuration of the present invention, bipolar I
An example in which the present invention is applied to C will be explained. A manufacturing method according to the present invention for a bipolar IC, which is an embodiment of the present invention, will be explained using FIG. 1 (cross-sectional view) showing each step. In all the figures of the embodiment, parts having the same functions are designated by the same reference numerals, and repeated explanations thereof will be omitted. As shown in FIG. 1A, an N-type conductive layer 2 is formed on a portion of a P-type silicon substrate 1, and an N-type silicon layer 3 is deposited thereon. An oxide film 4 is formed on the surface 3A of the N-type silicon layer, holes are made at predetermined positions in the oxide film 4 by photolithography, and a P-type conductive layer 5 is formed by diffusion technology to serve as an element isolation layer. Next, the surface oxide film 4 and the process oxide film 6 at the time of forming the element isolation layer are removed, and a new surface oxide film 7 is formed.As shown in FIG. A hole 8A is made at the position using photolithography technology. The etching end point of the surface oxide film 7 at this time can be determined by the drainage of water from the substrate surface at the same time as the etching of, for example, the left third portion 9A of the scribe line 9 is completed. A highly doped P-type conductive layer 8 is formed in this hole 8A by a diffusion technique. This high concentration P-type conductive layer 8
are the emitter and collector of the lateral type PNP transistor. Next, as shown in FIG. 1C, holes 11A and 12 are formed at predetermined positions in the process oxide film 10 of the surface oxide film 7 and the highly concentrated P-type conductive layer 8 by photolithography.
Open A. At this time, the etching end point of the oxide films 7 and 10 is the same as the hole etching of the highly concentrated P-type conductive layer 8, when the etching of the right one-third portion 9B of the scribe line 9 is completed, for example, and the end point of the etching is the end point of the etching from the substrate surface. This can be determined by draining water. Next, P-type conductive layers 11 and 12 are formed in the hole portions 11A and 12A by diffusion technology, and the NP
This is the base and resistance of the N transistor. Next, Figure 1 (D
), holes 14A, 15A, Open 16A. At this time, the etching end point of the oxide films 7, 10, and 13 can be determined by the water draining from the substrate surface when the etching of, for example, the central one-third portion 9C of the scribe line 9 is completed, as before. can. Drilled parts 14A, 15A
, 16A, N-type conductive layers 14, 15, 1 are formed by diffusion technology.
6 and a process oxide film 17 are formed. They become the emitter 14 and collector 15 of the NPN transistor and the base 16 of the PNP transistor. Furthermore, as shown in FIG. 1E, predetermined process oxide films 10, 13, 17 of the high concentration P-type conductive layer 8, P-type conductive layers 11, 12, and N-type conductive layers 14, 15, 16 are formed. Contact holes for taking out electrodes 8B, 8C, 11B, 12B, 12C, 1 at the positions of
4B, 15B, and 16B are opened using photolithography technology. The etching end point at this time can be determined by the completion of etching of the entire slive line 9 9A, 9B, and 9C and by the draining of water from the substrate surface. and,
Although not shown, the contact holes are further wired in a predetermined pattern and protected with a passivation film for protecting the device. Thereafter, the bipolar IC is completed by cutting it to a predetermined size, fixing it in a package, bonding the bonding pad and external terminal, and sealing it with resin or glass. As mentioned above, it goes without saying that the present invention is not limited to the above embodiments, and can be modified in various ways without departing from the gist thereof. For example, in the present invention,
An IC may be configured using an N-type silicon substrate, and although the etching end point was determined by dividing the scribe line into three, the number of divisions is not limited as long as the same effect is achieved.

[0007]

Effects of the Invention A method for manufacturing a semiconductor device comprising a silicon oxide film, a P-type conductive layer, an N-type conductive layer, and a process oxide film formed when forming these conductive layers on a silicon substrate, the method comprising: When etching a process oxide film, by dividing the scribe line part into multiple parts, the end point of the etching can be determined from just the scribe line part. It becomes possible to determine the etching end point of a film, and it is possible to reduce defects in semiconductor elements due to unetched oxide films or overetching.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing each manufacturing process of a method for manufacturing a bipolar IC, which is an embodiment of the present invention. FIG. 2 is a cross-sectional view showing each manufacturing process of a conventional bipolar IC manufacturing method.

[Explanation of symbols] 1 P-type silicon substrate 2 N-type conductive layer 3 N-type silicon layers 4, 7 Surface oxide films 6, 10, 13, 17 Process oxide film 8 High concentration P-type conductive layer 9 Scribe line portions 11, 12 P-type conductive layer 14, 15, 16 N-type conductive layer

Claims (1)

[Claims] Claim 1: A silicon oxide film that serves as a mask for selective diffusion and an electrical insulating film, a P-type conductive layer for element isolation, a highly concentrated P-type conductive layer necessary for lateral transistors, and the formation of transistor bases and resistance elements. P-type conductive layer necessary for forming the corester and emitter of the transistor, contact holes for electrode extraction made in the silicon oxide film on semiconductor elements such as the transistor and resistor, and these semiconductor elements. In manufacturing a semiconductor device, an electronic circuit is formed in between, aluminum or aluminum alloy wiring and bonding pads necessary for making a semiconductor device, and a passivation film that protects the semiconductor element and wiring from corrosion in the outside world, etc. The criteria for determining the etching end point in the hole-etching of the silicon oxide film necessary to form contact holes for taking out the P-type conductive layer, the N-type conductive layer, and the electrodes at predetermined positions is determined by determining the etching end point of each conductive layer. A method for manufacturing a semiconductor device, characterized in that the semiconductor device is provided at a scribe line portion for dividing the semiconductor device from the substrate, and the scribe line portion is divided into multiple parts.