JPS63248134A - Semiconductor device - Google Patents

Abstract

PURPOSE:To simplify the analysis of a product by a method wherein oxide films, whose thicknesses are different from each other, are continuously formed on the periphery of a semiconductor chip constituting a semiconductor device extending from the center of the chip to its outer periphery and these films are used as a monitor for the amount of etching. CONSTITUTION:A region 4, through which a semiconductor chip is exposed, is provided on the central part of the chip using the periphery of the chip and an about 0.1 mum thick oxide film 1 is formed encircling this region by an oxidation production method (LOCOS method). Then, a 0.4 mum thick oxide film 2 is formed around this film 1 by a LOCOS method and moreover, a 1.4 mum thick oxide film 3 is formed by a LOCOS method. In such a way, the films 1-3 are used as a monitor for etching and the thicknesses of the films are confirmed by a change in the colors at the time they are etched, that is, a generated milk white, a reflected color and so on. According to such a way, a means for peeling the films for analysis is not needed and to know simply the aim of the amount of etching becomes possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to a semiconductor device in which the amount of etching of a surface oxide film can be monitored during product analysis.

[Conventional technology]

When analyzing a semiconductor device (hereinafter referred to as a semiconductor chip), the surface of the device may be observed while peeling off an oxide film formed on the surface of the semiconductor.

For example, bipolar F with junction-destructive memory cells
When analyzing a memory cell of a ROM, microscopic observation of the memory cell is sometimes performed as one of the analysis methods. At this time, after removing the metallization, the state of the surface oxide film is observed while etching, and it is important to know the amount of the oxide film etched each time.

Another example is the analysis and investigation of scratches, dirt, etc. on the element surface of a semiconductor chip. In this case as well, the device surface is observed while peeling off the oxide film, but it is necessary to know how much the oxide film has been etched, and also to know in which oxide film formation process the scratches were created. is important. Conventionally, to perform such analysis, the oxide film was etched while comparing and referencing parts of the semiconductor chip whose oxide film thickness was known in advance, but the parts to be referenced were scattered widely within the semiconductor chip. If so, this method is cumbersome and error-prone. Additionally, this method requires thorough understanding of the manufacturing process, which can be difficult if the analyst and the person in charge of the process are different.

[Problem that the invention seeks to solve]

The present invention has been made to solve the above-mentioned conventional problems, and therefore, an object of the present invention is to provide a semiconductor device equipped with an appropriate check pattern for determining the amount of etching of the oxide film on the surface of a semiconductor chip. It is in.

[Failure to solve the problem]

The semiconductor device of the present invention includes a check button in which a plurality of layers of oxide film thickness are formed on the semiconductor surface by appropriately combining steps for forming an oxide film around the semi-integrated chip.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an embodiment of the present invention, and shows a check pattern when manufactured by the Locos method. Figure 1 (a
) is a plan view, and FIG. 2(b) is a sectional view taken along the line A' of the person. 2 is a tenth coating film forming button, and an oxide film of about 1.4 μm is formed on the parts other than 2. 1 is the 20th COS film forming button, and an oxide film of about 0.4 μm is formed between 1 and 2 (shaded area on the upper right). The button between 2 and 3 (shaded area on the upper left) is a contact etching button, and the thickness is approximately 0.
．． An oxide film of 7 μm is etched away, and therefore about 0.7 μm of the 10th cos film remains (C in FIG. 2B). Further, since 2 also serves as a collector barrier, an oxide film of about 0.1 μm is formed between 1 and 4. 4 is a contact etching button, so the inside of 4 is entirely made of silicon. The combination of the above-mentioned clicks will result in 0.
i p (a in Figure (b)) 0.4/J between 1 and 2 (Figure (b)
), b), 0.7 tt between 2-3 (C in figure (b)),
A total of four types of oxide film thicknesses of 1.4 μm (d in Figure (b)) can be formed on the outside.

Therefore, if you refer to this button when etching the oxide film,
If the area between 1 and 2 becomes a silicon base (milky white), it can be seen that it has been etched by about 0.4μ. Moreover, if the element part for analysis purposes is also made of silicon (milky white),
It can also be seen that that portion is an oxide film formed by the 20th cost process. Further, the amount of etching between one acid oxide film thickness and another oxide film thickness can be determined by the oxide film reflection color. Note that the size of the baton may be approximately several tens of microns both vertically and horizontally (X and Y). Of course, this check pattern can be used to monitor oxide film thickness variations within a wafer.Furthermore, by providing multiple check patterns around a semiconductor chip, it is also possible to monitor oxide film variations within the same chip. Useful information can also be obtained when manufacturing semiconductor chips.

[Embodiment 2] FIG. 2 is a second embodiment of the present invention, and shows a check pattern when manufactured by the in-planar method. (a
) is a plan view, and (b) is a BB' sectional view thereof. Reference numeral 11 denotes an isoplanar oxide film, and an oxide film of about 1.2 μm is formed on the portion other than 11. 12 is the second
This is a 0 cost film pattern, and an oxide film of about 0.5 μm is formed in this portion (the upper right diagonal line). 14 is a mask oxide film portion, and an oxide film of about 0.2 μm is formed in this N3 portion (upper left dotted line portion).

Reference numeral 13 denotes a CVD 5iOz forming step sb, which forms an oxide film of about 0.3 μm together with the underlying mask oxide film. Also 15
is a contact etching button, which etches the oxide film by about 0.4μ. Therefore, this part (dotted chain line part) is 0
．． An isobrener oxide film of about 8μ remains.

With the combination of the above-mentioned slams, 0.2μ for 14 (g in figure (b)), 0.3 for 13 (f in figure (b)), and 0.4 μ for 12 (e in figure (b)) , 0.8 μ in 15 (Figure (b)
In addition to h) 11 in ), it is possible to form a total of five different oxide film thicknesses of 1.2μ (i in Figure (b)).

As in the first embodiment, etching is performed while referring to this pattern, which has the advantage of making the analysis more accurate and convenient. It also has the advantage of being effective as a manufacturing monitor.

〔Effect of the invention〕

As explained above, according to the present invention, by providing a button for monitoring the oxide film around the semiconductor chip, it is convenient for analysis, and at the same time, it can be used to monitor the state of monolayer film formation during manufacturing. There is an effect.

[Brief explanation of drawings]

FIG. 1 shows a first embodiment of the present invention, and (3) is a plan view, and (b) is a sectional view taken along line A-A'. Figure 2 shows a second embodiment of the present invention, (a) is a plan view, (b)
) is its BB' cross-sectional view. 1...20th Cospatan, 2...1st
Locospatan, Collectorinbatan, 3,4...
・Contact etching pattern, 5...Epitaxial layer, 6...Buried layer, 7...Insulating layer, a...Mask oxide film thickness, b...・・・・・・
20th coating film thickness, C... Contact etched first coating thickness, d... 10th coating thickness, 11... Isoplanar baton oxide, 12.
・・・・・・20 happy costumes, 13・・・CVD
5iO□ formation button, 14...Mask ρ film part, 15...Contact etching button, e.
...Edict 20 Cosmembrane, f...CV D S
io is the film thickness, g...Mask genation film thickness, h
Contact-etched isoplanar oxidized ribs,
i・−・Isoplanar oxidation g+ thickness, 16・・
...Epitaxial layer, 17...Buried layer,
18... Channel stopper. −ゝ＼ Agent Patent Attorney Uchihara B'4-5'
increase

Claims (1)

[Claims] A semiconductor device comprising a check pattern in which a plurality of oxide film thicknesses are formed on a semiconductor surface by appropriately combining processes capable of forming an oxide film.