JPH09162190A - Method for manufacturing semiconductor device - Google Patents

Abstract

(57) An object of the present invention is to provide a method of manufacturing a semiconductor device having high reliability by removing contamination by mobile ions during manufacturing. SOLUTION: In a dicing line region 11 and 12 on a semiconductor wafer, linear electrodes 13 and 14 are provided so as to divide the outer periphery of each MOS type transistor T into two, and each electrode is provided with another electrode. It is connected to an electrode provided on the outer periphery of the MOS transistor T.
The temperature is raised, the movement of mobile ions is activated, and the electrode 1
A voltage is applied to 3 and 14 to create an electric field between the electrodes. Due to this electric field, the movable ions move from the inside of the MOS transistor T to the periphery of the electrodes 13 and 14.
After the temperature is returned to room temperature and the voltage application to the electrodes 13 and 14 is stopped, the dicing line regions 11 and 12 are removed in the dicing process, so that the mobile ions collected around the electrodes 13 and 14 are also removed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device manufacturing method, and more particularly to a manufacturing method for preventing contamination by mobile ions during manufacturing.

[0002]

2. Description of the Related Art A conventional semiconductor device has a passivation film made of phosphorus glass or the like, which has a gettering effect on mobile ions, on the surface of the semiconductor device in order to prevent contamination by impurities such as external mobile ions after completion of the device. The cover protects the inside of the semiconductor device. FIG. 5 is a sectional view showing the structure of a MOS transistor T which is an example of such a conventional semiconductor device. In the vicinity of the surface of the p-type semiconductor substrate 1, an n + region 2 serving as a source and an n + region serving as a drain.
Region 3 is formed. A gate electrode 5 made of polysilicon is provided via a gate oxide film 6 made of silicon covering one end of each of the n + regions 2 and 3. Aluminum layers 7 and 8 serving as wirings are provided on both sides of the gate oxide film 6, and the p + region 4 connects the aluminum layer 7 and the p-type semiconductor region 1. A field oxide film 9 made of silicon is provided outside the aluminum layers 7 and 8. The entire surface of the semiconductor device is covered with phosphor glass 30. In such a semiconductor device, even if mobile ions such as Na ions and K ions adhere to the surface of the semiconductor device after completion and try to enter, the mobile ions are gettered by the passivation film made of phosphorus glass, It does not reach inside the semiconductor device.

[0003]

However, in such a conventional semiconductor device, when mobile ions are mixed in during manufacturing, the mobile ions may reach the inside of the semiconductor device and interfere with normal circuit operation. It was For example, in the MOS transistor T of FIG.
When Na ions reach the interface with the type semiconductor substrate 1, an undesired channel is formed in the p-type semiconductor substrate 1 below the gate oxide film 6 due to the influence of the Na ions. Therefore, the original function of the transistor, which is to apply a voltage to the gate to control the current between the source and the drain, is impaired. Semiconductor devices contaminated with these mobile ions are discarded as defective products in the inspection process, but if the mobile ions do not reach the interface of the gate oxide film before the final inspection process and pass the final inspection process, they are regarded as good products. It will be shipped to the market. Since the moving speed of mobile ions in silicon increases in proportion to temperature, semiconductor semiconductor devices for automobiles, which are often used at higher temperatures than general-purpose semiconductor devices, may have problems during use. There was a problem with. Therefore, in view of the conventional problems described above, it is an object of the present invention to provide a method for manufacturing a semiconductor device having high reliability by removing contamination by mobile ions during manufacturing.

[0004]

In order to achieve the above object, the method of the present invention according to claim 1 forms two electrodes in the dicing line of the semiconductor wafer, which divides the outer periphery of the semiconductor unit into two. The step of heating the semiconductor wafer to apply a voltage to the two electrodes in a high temperature state to generate an electric field between the electrodes, and the step of applying a voltage between the electrodes after the temperature of the semiconductor wafer is lowered to room temperature. It has a step of stopping and a step of cutting off the dicing line including the electrode. Further, in the invention according to claim 2, the two electrodes are covered with a film having a gettering effect on the periphery of the two electrodes.

[0005]

According to the first aspect of the present invention, electrodes are provided in the dicing line in parallel with the formation of a large number of semiconductor units on the wafer. If the temperature of the semiconductor wafer is raised within a range that does not affect the semiconductor unit built in the wafer, the movement of mobile ions becomes active. In that state,
A voltage is applied to the two electrodes to generate an electric field between the electrodes.
Due to this electric field, the movable ions move through the semiconductor unit from the inside of the semiconductor unit to the periphery of the electrode in the dicing line. After the temperature of the semiconductor wafer is returned to room temperature and the voltage application to the electrodes is stopped, the dicing line region is removed in the dicing process, so that the mobile ions gathered around the electrodes in the dicing line are removed.

According to the second aspect of the present invention, mobile ions can be trapped by previously forming a film having a getter effect on mobile ions around the electrodes in the dicing line. As a result, even if the dicing line region partially remains, the movable ions do not move and do not adversely affect the inside of the semiconductor device.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to examples. 1, 2 and 3 are views showing a first embodiment of the present invention. FIG. 1 is a sectional view of a part of the wafer structure in one step of the present embodiment in which the present invention is applied to a semiconductor wafer having a MOS transistor built therein. FIG. 2 is an external view of a semiconductor wafer, in particular (a) is an overall view,
(B) is a partially enlarged view. FIG. 3 is a flowchart of the manufacturing process of this embodiment. FIG. 1 shows one of a plurality of MOS type transistors T formed in a semiconductor wafer and a dicing line region outside the one. The phosphor glass 10 covers only the surface of the MOS transistor T. Electrodes 13 and 14 provided in dicing line regions 11 and 12 are provided on field oxide film 9 and are connected to different terminals of power supply 18, respectively. The structure of the MOS transistor T is the same as that of the conventional example shown in FIG.

A plurality of MOS transistors T are divided and built in on a semiconductor wafer 19 as shown in FIG. This MOS type transistor T (or further including a large number of other functional elements) forms one semiconductor unit, and the plurality of semiconductor units are divided along the dicing line to form individual semiconductor devices. As shown in FIG. 2B, the linear electrode 1
3 and 14 are provided in dicing line regions 11 and 12 surrounding the outer periphery of each MOS transistor T. The electrodes 13 and 14 are formed by dividing the outer circumference of each MOS type transistor T (semiconductor unit) into two, and connecting two adjacent sides of a quadrangle surrounding each MOS type transistor T in a continuous manner to a length L, It is formed to have the same length as L. Each electrode is connected to an electrode provided on the outer periphery of another MOS transistor T (another semiconductor unit).

Next, the manufacturing process will be described with reference to the flowchart of FIG. First, in step 101, the dicing line region 11 is formed in parallel with the formation of the MOS transistor.
Electrodes 13 and 14 are provided in and 12. Next, in step 102, the semiconductor wafer 19 is heated within a range that does not affect the MOS transistor T built therein. When the temperature of the semiconductor wafer 19 rises, the movement of mobile ions becomes active.

In step 103, a voltage is applied to the two electrodes to generate an electric field between the electrodes. At this time, since the electrodes 13 and 14 surrounding each MOS transistor T are formed to have the same length, a uniform electric field can be obtained. Due to this electric field, the movable ions pass through the oxide film from the inside of the MOS transistor T to the electrodes 1 in the dicing line regions 11 and 12.
Move around 3 and 14. Since the semiconductor wafer 19 is in a high temperature state, the movement of mobile ions is effectively promoted.

Next, at step 104, heating is stopped and the temperature of the semiconductor wafer 19 is returned to room temperature. Step 105
At this point, the voltage application to the electrodes 13 and 14 is stopped. At step 106, an electrical inspection is performed. In step 107, by removing the dicing line regions 11 and 12 in the dicing process, mobile ions gathered around the electrodes 13 and 14 in the dicing line region are also removed.

Since this embodiment is constructed as described above, contamination due to mobile ions during manufacturing is removed,
A semiconductor device having high reliability can be manufactured. In addition, by performing the moving process of moving ions immediately before the electrical inspection,
The manufacturing yield can be improved.

Next, FIG. 4 shows a second embodiment of the present invention.
FIG. 4 shows one of a plurality of MOS transistors T built in a semiconductor wafer and a dicing line region outside the one. The phosphor glass 20 covers the surface of the MOS transistor T and the periphery of the electrodes 23 and 24. The other structure is similar to that shown in FIG. 1, and the electrodes 23 and 24 are provided on the field oxide film 9 in the dicing line regions 21 and 22 so that they can be connected to different terminals of the power supply 18. Further, the electrodes 23 and 24 are provided so as to divide the outer periphery of each MOS type transistor T into two, and each electrode is connected to the electrode provided on the outer periphery of another MOS type transistor T.

Also in this embodiment, a voltage is applied to the two electrodes to generate an electric field between the electrodes, and this electric field causes the movable ions to pass through the oxide film from the inside of the MOS transistor T to the dicing line region 21 and the dicing line region 21. Electrodes 23 in 24
And around 24. At this time, mobile ions are trapped by the getter effect of the phosphor glass 20 around the electrodes 23 and 24. The mobile ions once trapped in the phosphor glass 20 do not move even if an electric field is generated after being trapped or when the temperature is high. Then, by removing the dicing line regions 21 and 22, the mobile ions collected around the electrodes 23 and 24 in the dicing region are also removed.

In this embodiment, the phosphorus glass 2
Since the movable ions trapped at 0 do not move, there is an advantage that no problem occurs during use even when the dicing line regions 21 and 22 are not removed or partially left. Thereby, the first
Since the same effect as that of the above embodiment can be obtained and mobile ions are trapped, a semiconductor device with further improved reliability can be manufactured.

[0016]

As described above, according to the present invention, two electrodes that divide the outer periphery of the semiconductor unit into two are formed in the dicing line of the semiconductor wafer, and a voltage is applied to the two electrodes at a high temperature, After generating an electric field between them and collecting the mobile ions around the electrodes, the temperature of the semiconductor wafer is lowered to room temperature, the voltage application between the electrodes is stopped, and the periphery of the electrodes including the mobile ions is cut off in the dicing process. A highly reliable semiconductor device can be manufactured by removing contamination due to mobile ions during manufacturing. In addition, by providing a film having a getter effect against mobile ions around the electrodes in the dicing line, mobile ions can be trapped, and even when the dicing line region partially remains, the trapped ions re-migrate. Therefore, a semiconductor device with further improved reliability can be manufactured.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a wafer showing a first embodiment of the present invention.

FIG. 2 is an external view of the first embodiment.

FIG. 3 is a flow chart of a manufacturing process of the first embodiment.

FIG. 4 is a cross-sectional view of a wafer showing a second embodiment of the present invention.

FIG. 5 is a sectional view of a wafer showing a conventional example.

[Explanation of symbols]

 1 p-type semiconductor substrate 2 n + region 3 n + region 4 p + region 5 gate electrode 6 gate oxide film 7, 8 aluminum layer 9 field oxide film 10, 20, 30 phosphorus glass 11, 12, 21, 22 dicing line region 13, 14 , 23, 24 electrode 18 power supply 19 semiconductor wafer T MOS type transistor (semiconductor unit)

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location H01L 29/78 H01L 29/78 301N

Claims (3)

[Claims] 1. A step of forming two electrodes for dividing an outer periphery of a semiconductor unit into two in a dicing line of a semiconductor wafer, and heating the semiconductor wafer to apply a voltage to the two electrodes in a high temperature state. Then, the method comprises the steps of generating an electric field between the electrodes, subsequently lowering the temperature of the semiconductor wafer to room temperature and then stopping the voltage application between the electrodes, and cutting the dicing line including the electrodes. A method for manufacturing a semiconductor device, comprising: 2. A step of dividing an outer periphery of a semiconductor unit into two parts in a dicing line of a semiconductor wafer, and forming two electrodes whose periphery is covered with a film having a getter effect against mobile ions, and a step of adding the semiconductor wafer. A method of manufacturing a semiconductor device, comprising a step of applying a voltage to the two electrodes in a high temperature state by heating to generate an electric field between the electrodes. 3. The semiconductor device according to claim 1, wherein the two electrodes are formed to be equal in length by arranging adjacent two sides in a quadrangle surrounding the semiconductor unit. Production method.