KR100605608B1 - Semiconductor memory device and method for fabricating the same - Google Patents

Abstract

The present invention is to provide a semiconductor memory device that can prevent corrosion even when using a metal wiring as a fuse, for the purpose of the present invention to form a buffer film consisting of a bit line conductive film on the substrate, the buffer film on the Forming a first interlayer insulating film, forming a fuse on the first interlayer insulating film, forming a second interlayer insulating film on the fuse, and connecting both ends of the fuse through the second interlayer insulating film Forming a contact plug which is connected to the buffer layer through the second interlayer insulating film, the fuse, and the first interlayer insulating film in the front region of the contact plug, and forms a corrosion preventing dummy contact plug made of tungsten or copper, respectively; In the second contact gap between the dummy contact plugs so that a portion of the second interlayer insulating film remains on the fuse. It provides a cross forming a fuse box by selectively etching the insulating film, and a semiconductor memory device manufacturing method on the dummy contact plugs comprises: forming a dummy metal line pattern for the dummy contact plug protection.

Semiconductor, Memory, Repair, Fuse, Corrosion, Contact.

Description

Semiconductor memory device and manufacturing method therefor {SEMICONDUCTOR MEMORY DEVICE AND METHOD FOR FABRICATING THE SAME}             

1 is a cross-sectional view of a conventional semiconductor memory device.

2 is a cross-sectional view of a semiconductor memory device according to the prior art.

3 is a plan view of the semiconductor memory device shown in FIG.

4 is a cross-sectional view of a semiconductor memory device according to a preferred embodiment of the present invention.

FIG. 5 is a plan view of the semiconductor memory device shown in FIG.

Fig. 6 is a sectional view of a semiconductor memory device according to the second embodiment of the present invention.

Fig. 7 is a sectional view of a semiconductor memory device according to the third embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

59: fuse

60: Fuse contact for corrosion protection

62: contact

63: metal wiring

66: fuse box

52, 57, 58, 61, 64: interlayer insulating film

65: passivation film

The present invention relates to a semiconductor memory device, and more particularly, to a fuse of a semiconductor memory device in which a laser is irradiated and blown during a repair process.

In the manufacture of a semiconductor device, especially a memory device, if any one of a number of fine cells is defective, the semiconductor device does not function as a memory and thus is treated as a defective product. However, despite the fact that only a few cells in the memory have failed, discarding the entire device as defective is an inefficient process in terms of yield.

Therefore, the yield improvement is achieved by replacing the defective cell by using a spare cell (also referred to as a redundancy cell) previously installed in the memory device.

In the repair operation using redundancy cells, spare memory arrays and spare column arrays are pre-installed for each cell array so that defective memory cells having defects are stored in row / column units. It proceeds in a cell-like manner.

In detail, when a defective memory cell is selected through a test after completion of a wafer state, a program is executed in an internal circuit to change a corresponding address into an address signal of a spare cell. Therefore, in actual use, when an address signal corresponding to a defective line is input, the selection is changed to a spare cell instead of the defective cell.

Among the above-described program methods, the most widely used method is to burn a fuse with a laser beam and blow it. The wiring broken by the laser irradiation is called a fuse, and the broken portion and the area surrounding the fuse box are called fuse boxes. .

1 is a cross-sectional view showing a conventional semiconductor memory device, with a left side showing a cross section of a cell region and a right side showing a fuse region.

As shown in FIG. 1, a cell region of a semiconductor memory device may include a device isolation layer 11, an active region 13, a gate pattern 14, and first and second storage node contact plugs 15a on a substrate 10. 17, the bit line contact plug 15b, the bit line 16, the storage node contact plug 19 forming the capacitor and the interlayer insulating films 12, 17, and 22, the dielectric thin film 20, and the plate electrode 23 24). The plate electrodes 23 and 24 are composed of a polysilicon film 23 and a TiN film 24. The titanium film 24 may be formed of another metal.

The fuse region of the semiconductor memory device is a fuse composed of interlayer insulating films 11 ', 17' and 22 ', a polysilicon film 23' and a TiN film 24 'on a substrate, and an interlayer insulating film formed on the fuse. (26) is provided. In addition, reference numeral 26 denotes a fuse box formed by removing the interlayer insulating film 21 on the upper portion of the fuse by a predetermined thickness for cutting the fuse by laser irradiation during the repair process. The interlayer insulating films 11 ', 17', and 22 'are not formed separately, but are formed together when the interlayer insulating films 11, 17, and 22 are formed in the cell region.

As described above, the fuse is used to repair a defective portion of the semiconductor memory device in the event of a failure. In general, the fuse is not formed by an additional process, but a bit line or a word in a cell region. It is formed using a conductive layer such as a word line.

In particular, in recent years, as the degree of integration of semiconductor memory devices increases, the height of structures of semiconductor memory devices also increases. As a result, when fuses are formed by using word lines or bit lines, which are relatively substructures, interlayers are formed to form fuse boxes. The difficulty of removing the insulating film has arisen. Therefore, in recent years, a conductive layer formed at a high position of a semiconductor memory device is used as a fuse line, and a conductive film for electrodes of metal wiring or capacitor is used as a fuse line.

The fuses 23 'and 24' shown in Fig. 1 are formed using a conductive film forming the plate electrodes 23 and 24 of the capacitor formed in the cell region.

FIG. 2 is a cross-sectional view of a semiconductor memory device according to the related art, showing in detail a region in which a fuse is formed in FIG. For reference, the same reference numerals are used for the same layers.

Referring to FIG. 2, in the semiconductor memory device according to the related art, a gate pattern 14 is formed on a substrate 10 on which an isolation layer 11 is formed, and an interlayer insulating layer 12 ′ is formed on the substrate 10. have.

Subsequently, a metal buffer film 16 'and a contact 32 formed in a bit line pattern are formed on the upper portion thereof, and a fuse 30 is formed on the upper portion thereof.

Subsequently, a plurality of interlayer insulating films 31, 34, 37, metal wires 36, 33, and contacts 35, 32 are stacked on the fuse. Finally, the passivation film 38 is formed.

A fuse box 26 is formed on the upper end of the fuse to irradiate a laser during the repair process. The fuse box 26 is an area in which only the insulating film having a predetermined thickness is left on the upper end of the fuse and the remaining insulating film is removed.

3 is a plan view of the semiconductor memory device shown in FIG.

Referring to FIG. 3, the fuses 24 ′ and 23 ′ pass through the fuse box 26.

As described above, one used as a bit line or a word line as a fuse is formed by using an electrode film of a capacitor.

The capacitor electrode film is formed at a relatively higher position than the bit line or the word line, but as the semiconductor memory device is highly integrated, a plurality of metal wirings are used, and thus many layers are formed on the electrode film of the capacitor.

Therefore, even when the electrode film of the capacitor is used as a fuse, it is difficult to remove many interlayer insulating films in order to form a fuse box.

It is very important for a reliable repair process to leave an insulating film of constant thickness on the top of the fuse (see X in FIG. 2) when forming the fuse box.

However, even when the electrode film of the capacitor is used as a fuse, the thickness of the insulating film to be selectively removed to form a fuse box is so thick that it is very difficult to leave a certain thickness of insulating film on top of the fuse (see Fig. 2 Y).

To solve this problem, a metal wiring formed at a higher position than the electrode film of the capacitor is sometimes used as a fuse. However, since the metal wiring is generally formed of titanium, aluminum, etc., which are well corroded, a problem arises in that the fuse part is corroded by moisture penetrated through the fuse box.

If the fuse is corroded, corrosion continues to the metal wiring connected to the fuse, which may cause a defect, so it is difficult to use the metal wiring as a fuse.

The present invention has been proposed to solve the above problems, and an object of the present invention is to provide a semiconductor memory device and a method of manufacturing the same, which can prevent corrosion even when a metal wiring is used as a fuse.

The present invention provides a method of forming a buffer layer including a bit line conductive layer on an upper surface of a substrate, forming a first interlayer insulating layer on the buffer layer, forming a fuse on the first interlayer insulating layer, and forming a fuse on the fuse layer. Forming a second interlayer insulating film, forming a contact plug penetrating the second interlayer insulating film and connected to both ends of the fuse; and forming a second interlayer insulating film, a fuse, and a first interlayer insulating film in a front region of the contact plug. Forming a corrosion preventing dummy contact plug made of tungsten or copper, respectively, passing through the buffer layer, and the second interlayer insulating film between the dummy contact plugs so that a portion of the second interlayer insulating film remains on the fuse. Selectively etching to form a fuse box, and the dummy contact plug protection on the dummy contact plug. It provides a method for manufacturing a semiconductor memory device comprising forming a dummy metal wiring pattern for.

The present invention also provides a substrate, a buffer film formed over the substrate and formed as a conductive film for bit lines, a first interlayer insulating film formed on the buffer film, a fuse formed on the first interlayer insulating film, and a second formed on the fuse. A contact plug for connecting the fuse and the metal wiring to the both ends of the fuse through the interlayer insulating film and the second interlayer insulating film; and the second interlayer insulating film between the fuse box region to be blown during the repair process and the contact plug. And a dummy contact plug for preventing corrosion, which is connected to the buffer layer through the fuse and the first interlayer insulating film, and is formed of tungsten or copper, and a dummy metal wiring pattern provided on the dummy contact plug to protect the dummy contact plug. A semiconductor memory device is provided.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention. do.

4 is a cross-sectional view of a semiconductor memory device according to a preferred embodiment of the present invention.

Referring to FIG. 4, in the method of manufacturing a semiconductor memory device according to the present embodiment, a gate pattern 54 is formed on a substrate 50 on which an isolation layer 51 is formed.

Subsequently, an interlayer insulating film 52 is formed thereon, and an interlayer insulating film 57 is formed again thereon.

Subsequently, an interlayer insulating film 58 is formed, and a fuse 59 is formed thereon.

The interlayer insulating films 52, 57, and 58 are formed of an undoped-silicate glass (USG) film, a phospho-silicate glass (PSG) film, a boro-phospho-silicate glass (BPSG) film, a high density plasma (HDP) oxide film, and a spin (SOG) film. On glass (TEOS) film, TEOS (Tetra Ethyl Ortho Silicate) film or HDP (oxidized film using high densigy plasma), etc., or thermal oxide (Thermal Oxide) formed by oxidizing the silicon substrate at a high temperature of 600 ~ 1,100 ℃ in the furnace Membrane).

The fuse 59 is formed by using a conductive film used as metal wiring in a cell region such as an aluminum film, a titanium drop, or a titanium nitride film. Alternatively, the capacitor may be formed by using upper and lower electrode films or conductive films for bit lines or word lines.

The fuse 59 is formed in a region where the fuse is to be formed by one film, and then selectively removes the fuse 59 in the region where the corrosion preventing contact plug 60 is to be formed.

Next, the interlayer insulating film 61 is formed, and the interlayer insulating film 61 in the region where the contact 62 is to be formed and the interlayer insulating layer 61 in the region where the dummy contact plug 60 are to be formed are selectively removed.

At this time, in the region where the dummy contact plug 60 is to be formed, the interlayer insulating film 58 is selectively removed through the place where the fuse is removed.

Subsequently, the corrosion preventing contact plug 60 and the contact 62 are formed using tungsten or copper. Therefore, the fuse blown portion is to be electrically connected through the contact plug for preventing corrosion (60).

Subsequently, metal wires 63 connected to the contact 62 connected to both sides of the fuse are formed.

Next, an interlayer insulating film 64 is formed, and a passivation film 65 is formed thereon.

Subsequently, in order to form a fuse box 66 to which the fuse is to be irradiated during the repair process, the insulating film formed on the upper end of the fuse between the dummy contact plugs 60 is selectively removed.

The fuse box 66 is more exposed than other parts of the semiconductor memory device, and thus foreign matter such as moisture is easily penetrated.

In this case, when the fuse 66 is formed of a metal wire or the like, the corrosion is generally well performed. Even though the fuse at the bottom of the fuse box becomes corroded due to moisture penetrated through the fuse box, the corrosion proceeds through the fuse. In the semiconductor memory device according to the present invention, since the dummy contact plugs 60 for preventing corrosion are provided on both sides of the fuse, corrosion does not proceed anymore.

This is because the corrosion preventing dummy contact plug 60 is made of a material that is very resistant to corrosion such as tungsten or copper.

FIG. 5 is a plan view of the semiconductor memory device shown in FIG. 4.

As shown in Fig. 5, the semiconductor memory device according to the present embodiment is divided into three patterns in cross-section, and the separated pieces are connected to the dummy contact plugs 60 for preventing corrosion.

In FIG. 5, A indicates separation, and B and C indicate that a contact plug is formed.

6 is a cross-sectional view of a semiconductor memory device according to a second embodiment of the present invention.

Referring to FIG. 6, before the dummy contact plug 60 is formed, the semiconductor memory device according to the second embodiment may form a buffer film at a lower end thereof, and the dummy contact plug 60 may be connected to the buffer film 56. To form. In this way, the dummy contact plug 60 can be more stably formed (see D).

The buffer film 56 may be formed using a conductive film formed below the fuse. In the present embodiment, the buffer film 56 is formed using a bit line conductive film.

7 is a cross-sectional view of a semiconductor memory device according to a third embodiment of the present invention.

Referring to FIG. 7, in the semiconductor memory device according to the third exemplary embodiment, a dummy metal wiring pattern 67 is further formed on the dummy contact plug 60.

The dummy metal wiring pattern 67 formed on the top of the dummy contact plug 60 acts as a protective film of the dummy contact plug 60 to form the metal wire 63 before the subsequent process (for example, to form the interlayer insulating film 64). Patterning process, etc.) prevents the top of the dummy contact plug from being damaged.

In addition, although not shown, all of the techniques presented in the second and third embodiments can be applied. That is, the buffer film may be formed on the lower end of the dummy contact plug, and the dummy metal wiring pattern may be formed on the upper part of the dummy contact plug.

Although the technical idea of the present invention has been described in detail according to the above preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

The semiconductor memory device according to the present invention can prevent defects due to corrosion even when metal wiring is used as a fuse.

Therefore, if a metal wiring lamp located at a relatively high position is used as a fuse, the insulation film to be removed to form a fuse box is relatively small, and thus a fuse box can be formed more stably, thereby enabling a reliable repair process. .

Claims (14)

delete delete delete delete delete Forming a buffer film formed of a bit line conductive film on the substrate; Forming a first interlayer dielectric layer on the buffer layer; Forming a fuse on the first interlayer insulating film; Forming a second interlayer insulating film on the fuse; Forming a contact plug penetrating the second interlayer insulating film and connected to both ends of the fuse; Forming a corrosion preventing dummy contact plug made of tungsten or copper through the second interlayer insulating film, the fuse, and the first interlayer insulating film in the front region of the contact plug; Forming a fuse box by selectively etching the second interlayer insulating layer between the dummy contact plugs so that a portion of the second interlayer insulating layer remains on the fuse; And Forming a dummy metal wiring pattern on the dummy contact plug to protect the dummy contact plug; Method of manufacturing a semiconductor memory device comprising a. delete delete delete delete delete delete delete Board; A buffer film formed on the substrate and formed of a conductive film for bit lines; A first interlayer insulating film formed over the buffer film; A fuse formed on the first interlayer insulating film; A second interlayer insulating film formed on the fuse; A contact plug connected to both ends of the fuse through the second interlayer insulating film to connect a metal wiring to the fuse; A corrosion preventing dummy contact plug formed between tungsten or copper and penetrating the second interlayer insulating film, the fuse, and the first interlayer insulating film, respectively, between the fuse box region to be blown during the repair process and the contact plug; And Dummy metal wiring patterns provided on the dummy contact plugs to protect the dummy contact plugs A semiconductor memory device having a.

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