JPS58165342A - Semiconductor ic and programing method thereof - Google Patents

Abstract

PURPOSE:To perform a laser diffusion program having no thermal influence upon the same by a method wherein a programing circuit for power supply and two power supply pads are provided in addition to a programing circuit to perform the final diffusion of P utilizing the Joule heat of power supply. CONSTITUTION:Circuit programing elements 2a-2z and wirings are provided on an insulative film while another wirings common to elements 2a-2z and pads 14, 15 are further provided to connect to the other ends of the wiring of said elements 2a-2z and the power supply programing elements 10a-10z, common wirings and pads are provided. When a programing high resistant poly Si wiring is irradiated by laser, the wiring is preliminarily made low resistant by a laser power much lower than the damage threshold value then the poly Si wiring is supplied with minute current to accelerate diffusion by the self heating of the high resistant section attaining to satisfactorily low resistant value.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to programming of semiconductor integrated circuits. In particular, the present invention relates to a programming method that achieves high productivity without requiring highly accurate laser irradiation by using electric resistance heating in combination with laser irradiation in circuit programming.

Fabricated circuit chips can be programmed by cutting or shorting some of the integrated circuit wiring. Conventionally, the programming method has been used, for example, to program read-only memo 9 (ROM), etc.
Recently, it has been used to repair defects in memory devices.

These conventional methods usually use the following method.

+1) The current blows out the fuse and cuts the wiring.

(2) Optical energy is applied externally using laser pulses to cut and connect wiring.

FIG. 1 shows the circuit configuration of this prior art, in which regular memory cell rows 1a-1z are connected to programming elements 2a-2a.
It is connected to the regular circuit via 2t. The spare memory cell column 3 is connected in parallel to the programming elements 2a to 22, and if a defect is found in one of the regular memory cell columns 1α to 1z, for example, memory cell column 1y,
The 17K connected wiring is switched to the spare memory cell column 3 using the programming element 2y.

FIG. 2(α) #(b) is an example of a conventional technique in which wiring is cut for this switching. From Si substrate 4 to Si film 5
In this method, a laser beam 8 is irradiated onto a polycrystalline Si or M wiring 6 electrically insulated by a polycrystalline Si or M wiring 6 through a passivation film 7 placed thereon, and the wiring is cut to perform programming. This - Example Toshite, R,p, Canke
r et al. (19791SSCCDiggst of Tec
hnical pap, art), MOS me,
1' Change in the wiring of the warp decoder 11. Experimental results have been shown in which a cell connected to a defective memory cell is disconnected and replaced with a non-defective cell connected to a memory card. However, this method of cutting elements has the following drawbacks.

(1; A large amount of laser energy is required, and in addition, as shown in FIG. 2 (α) K, the wiring portion and surrounding material 9 that melt and scatter during cutting may damage the nearby passivation film 7, and the laser beam 8 tends to damage nearby boards.

Therefore, a sufficient margin is required in the layout, resulting in a large area.

(2) In addition, even if the area is large, when laser irradiation is performed on the cut section, K should be set at 5μ, for example, so as not to affect the surrounding area.
For abusive patterns, a sufficiently high positional accuracy of ±1μ is required, and in order to perform high-speed processing during mass production,
This requires the device to satisfy the contradictory demands of high speed and high precision at the same time, and even if it can be realized, it will be very expensive. In addition, placing functional elements around the cutting area also improves reliability.
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(3) Cutting alone may not be sufficient, and shorting may be advantageous in terms of the area occupied by the chip.

FIG. 3 shows another example of the prior art.
Electrically insulated by Ot film 5, low resistance polycrystalline Si
The high-resistance polycrystalline Si wiring 6b (resistance value 1010Ω) sandwiched between the wires @6α is irradiated with a laser 8 through the passivation film 7 overlaid on it to lower the resistance of the high-resistance polycrystalline Si wires @6h. A technology has been proposed that connects the However, this method of wiring connection is
It has the following drawbacks.

(11) In order to sufficiently lower the resistance value, the laser irradiation power density must be increased to near the damage threshold.
Therefore, laser irradiation is likely to cause damage to the periphery of the substrate.

Therefore, a sufficient margin is required in the layout, resulting in a large area.

(2) Also, even if the area is large, sufficiently high positional accuracy is required to suppress the influence on the surrounding area when irradiating the laser to the connection part, and the equipment is quite expensive to process at high speed during mass production. Become. Furthermore, it is difficult to place functional elements around the connection portion from the viewpoint of reliability.

(3) There are cases where the procedure of connection alone is insufficient, and combining disconnection may be advantageous in terms of the area occupied by the chip.

FIGS. 4 to 6 are diagrams showing problems when functional elements are disposed around wiring for cutting or connecting in the prior art. FIG. 4 is a plan view, and FIGS. 5 and 6 are sectional views taken along line 1-B and line CD in FIG. 4, respectively. Si0. The poly-Si or M wiring 6dK laser 8 provided across @5 is irradiated to cut the poly-Si or M wiring @6d or connect the polySi wiring 6d. However, 2
The size of the laser 8 that irradiates the wiring @ 6d is 1lA6 in practice, because it is possible to position the wiring part of ~3 μm with high precision and to process it at high speed, which places a heavy burden on the equipment.
I can't help but think that it is considerably larger than the size of d. Then, in the case of this conventional example, if there is a functional part 15 that is likely to be affected by heat among the functional parts 14 provided on both sides of the wiring 6d, then K is obtained. Therefore, in order to achieve high processing speed at the expense of some degree of accuracy, it is necessary to place the functional part as far away from the laser irradiation part as possible, and an increase in the area of the chip is unavoidable.

Note that 10 is phosphor glass, 11 is Si, N4, 12 is first layer M wiring, and 13 is second layer M wiring.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art and to provide a semiconductor integrated circuit and a programming method for the same, which allow programming of a high-density integrated circuit at high speed and with high reliability.

That is, in the present invention, on an insulating film provided on a semiconductor substrate,
The circuit programming elements and wiring are set up using common wiring and paths for the circuit programming elements.

This semi-conductor integrated circuit is characterized in that it is connected to the wiring at the other end of the mosquito circuit programming element, and is provided with an energizing programming element and a common wiring and pad. k, 1.11. :l,l:
, II, II'.

,,:・1 item: ,,' The present invention also provides high resistance poly-5 for problem
When irradiating an i-wire with a laser, the resistance is preliminarily reduced using a laser power much lower than the damage threshold, and then this poly
In this method, a minute current is passed through the -5i wiring to promote diffusion through self-heating of the high-resistance portion, thereby obtaining a sufficiently low resistance value.

The present invention will be specifically described below based on embodiments shown in the drawings.

FIG. 7 is a circuit diagram showing an embodiment of the present invention. If there is a defective cell in column 1y of the regular memory cell columns 1α to 1z, switching 1y to spare cell column 3 will prevent the chip from becoming defective. Therefore, a laser beam is irradiated to a predetermined portion of 2y among the program circuits 2a to 2z provided in advance to switch the circuit from 1y to 5. As shown in Fig. 6, this program circuit has a low resistance point 9S.
It consists of high-resistance board 9Si wiring sandwiched between
, (5 x 10' to 2 x 107 Ir/cd) laser light is irradiated, and the high-resistance poly-Si in the programmable part is ''.

Preliminary degree (resistance is reduced to around 1 MΩ. At the same time, among the energizing program circuits 104 to 10z having a similar structure, t
A predetermined program portion of the oy is also irradiated with the same low power and density laser beam to adjust it to around 1MΩ. Next, program circuits 2α to 2z and energizing program circuits 10α to
A current-carrying pad 14 commonly connected to 102.
15 to apply a voltage of 5 times. A 1MΩ resistor is inserted into the program circuit 11 of the pad 14.

Therefore, when switching memory cell row 1y to 3, 2
y, 10yiC weak laser beam irradiation, each 1MΩ
After switching back and forth, 5V is applied using pads 14 and 15. Then, a current of about t7μA flows through 2y, and 2.9
Generates μW of heat. In 1 second, it corresponds to 2.9 μ), which is 10
-11- The poly-Si can be heated to a sufficiently high temperature.

Since the high-resistance poly-Si of the program element is surrounded by an insulator with low thermal conductivity such as Sin, when electricity is applied, the state is close to adiabatic heating, and the temperature becomes high enough to cause P diffusion.

For this reason, the diffusion of P that has diffused from the low-resistance poly-9Si side due to laser irradiation further progresses, and the resistance value of the poly-Si in the program area, which was about 1 MΩ, decreases to 108-104 Ω, which is necessary for the process of lowering the resistance. is completed -1° As explained above, the present invention, in addition to the program circuit,
A program circuit for energization and two energization pads are provided, and the final diffusion of P is performed using Joule heat due to energization, so the laser power density during laser irradiation is kept sufficiently low, and there is no fear of thermal effects. This has the advantage of allowing laser diffusion programming to be performed.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the arrangement of a conventional bit relief program element and its drawbacks, Fig. 2 (←), (A) is a diagram showing an example of a conventional technique for cutting wiring, and Fig. 3 is an explanatory diagram showing the arrangement of a conventional bit relief program element and its drawbacks. Figures 4, 5, and 6 are diagrams showing problems in the method shown in Figure 3.
The figure shows an embodiment of the present invention. 1α~1z・・・・・・Regular memory cell row 3
・・・・・・・・・・・・・・・・・・・・・・Spare cell rows 2α to 2z・・・・・・・・・・・・Program circuits 10a to 1
0Z...Program circuit for energization 14.15...
・・・・・・Patent attorney representing Pad Susuki 1) Interest, -2
Oh my god! Figure 1 Figure 2 <a> 1 no ~ 4 (1)) ρ4 Figure 3 Figure 4 Flash, 4 A Supply 5 Figure 7 Continuation of Figure 1 page 0 Inventor Osamu Minato 280 Higashi Koigakubo-chome, Kokubunji City Inside the Central Research Laboratory, Hitachi, Ltd. 0 Inventor: Kotabe Nishimura, 1450 Kamimizu Honmachi, Kodaira City, inside the Musashi Factory, Hitachi, Ltd.

Claims (1)

[Claims] 1. A circuit programming element and a wiring are provided on an insulating film provided on a semiconductor substrate, a wiring and a pad common to the circuit programming element are provided, and the other end of the nuclear circuit programming element is provided. What is claimed is: 1. A semiconductor integrated circuit characterized in that a programming element for energization and a common wiring and pad are provided by IHK connection. 2. Pre-program the circuit programming element with a low level of power density that does not leave a thermal effect even when irradiated to the functional part, and then use the change in resistance value to cause energization,
A circuit programming method for a semiconductor integrated circuit characterized in that programming is completed by completing diffusion using this heat generation.