JPH04313080A - Semiconductor testing method - Google Patents

Abstract

PURPOSE:To make it possible to judge correct quality even under the fluctuation of temperature environment by correcting the electric characteristic into the measured values under the predetermined temperature environment based on the measured value of the test environment temperature of a semiconductor device under test. CONSTITUTION:The environment temperature (e.g. 27 deg.C) during the test is measured with a temperature sensor which is attached to a semiconductor testing apparatus. Then, the stand-by current of a semiconductor memory device under test is measured. The measured value of the stand-by current is corrected based on the measured environment temperature so that the value becomes the standby current value under the temperature (e.g. 25 deg.C) for ensuring the specified value of the semiconductor memory device. The corrected measured value is compared with a judging value. When the measured value is smaller than the judging value as a result of the non-defective product. When the measured value is larger than the judging value, the device is judged as the defective product.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor testing method for testing semiconductor devices such as semiconductor memory devices having temperature characteristics.

0002

2. Description of the Related Art The performance of semiconductor memory devices is guaranteed at a certain temperature (for example, 25° C.). The guaranteed performance under a certain temperature is called the standard value. Although it is desirable that the test environment for semiconductor memory devices be conducted at a temperature that guarantees standard values, testing is usually performed within a certain temperature range (for example, 25±3° C.). Semiconductor memory devices have characteristics that are influenced by environmental temperature; for example, standby current has a characteristic that increases as the environmental temperature rises.

FIG. 3 is a flowchart showing a procedure for testing a semiconductor memory device using a conventional semiconductor testing device. As shown in the figure, the standby current of the semiconductor memory device under test is first measured, and the measured value is compared with a judgment value determined in advance and input into this semiconductor testing equipment to determine whether it is a good product or a defective product. I do.

FIG. 2 is a diagram showing an example of the temperature characteristics of standby current of a semiconductor memory device. A semiconductor test equipment for testing a semiconductor memory device under test having temperature characteristics as shown by solid line 1 in Figure 2 is installed in an environment controlled at 25±3°C, and standby current is tested under this temperature environment. Assume that the following is performed. When the environmental temperature during the test is 25°C, the measured value of the standby current of the semiconductor storage device under test is a,
Since this value is smaller than the determination value A, the semiconductor memory device under test is determined to be non-defective. On the other hand, when the environmental temperature during the test is 27° C., the measured value of the standby current is b, which is larger than the determination value A, and therefore the semiconductor memory device under test is determined to be a defective product.

[0005]

[Problems to be Solved by the Invention] As described above, conventional semiconductor memory device testing is conducted over a certain temperature range (for example, 25±3
Since the test was conducted under an environmental temperature controlled within 10° C., the standby current of the semiconductor memory device under test fluctuates within this temperature range. Therefore, the ambient temperature (2
5° C.), there is a problem in that a product that should be determined to be a good product may be determined to be a defective product, or conversely, a defective product may be determined to be a non-defective product.

[0006] Furthermore, although semiconductor test equipment is installed in a room with controlled environmental temperature, the temperature varies depending on the location within the room. Differences occur in the environmental temperature, and therefore, when testing is performed using a plurality of semiconductor test apparatuses, there are problems such as different judgment results depending on the semiconductor test apparatuses.

The present invention has been made in order to solve the above-mentioned problems, and provides a semiconductor testing method that can correctly determine the acceptability of a semiconductor device under test even if there are fluctuations in the temperature environment during the test. The purpose is to obtain.

[0008]

[Means for Solving the Problems] A semiconductor testing method according to the first invention measures electrical characteristic values of a semiconductor device under test and compares the measured values with judgment values under a predetermined temperature environment. In a semiconductor testing method in which pass/fail is determined based on the test, there is a step of measuring the test environment temperature of the semiconductor device under test, and prior to the determination, the measured values of the electrical characteristics are determined in advance based on the measured value of the test environment temperature. and a step of correcting the measured value under the specified temperature environment.

A semiconductor testing method according to a second aspect of the present invention is a semiconductor testing method in which electrical characteristic values of a semiconductor device under test are measured and the measured values are compared with judgment values to determine pass/fail. The method includes a step of measuring the test environment temperature of the device, and a step of correcting the determination value based on the measured value of the test environment temperature prior to determination.

0010

[Operation] In the first invention, prior to pass/fail judgment, the measured values of the electrical characteristics of the semiconductor device under test are corrected to the measured values under a predetermined temperature environment based on the measured value of the test environment temperature. Therefore, it is possible to eliminate the influence of fluctuations in test environment temperature on pass/fail judgments.

[0011] Furthermore, in the second invention, the judgment value is corrected based on the measured value of the test environment temperature prior to the pass/fail judgment, so that the influence of fluctuations in the test environment temperature on the pass/fail judgment can be eliminated. Can be done.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a flowchart showing a test procedure for a semiconductor memory device according to the present invention. As shown in the figure,
First, the environmental temperature (for example, 27° C.) during the test is measured by a temperature sensor attached to the semiconductor testing equipment. Next, the standby current of the semiconductor memory device under test is measured. The measured value of the standby current is corrected based on the environmental temperature measured above so that it becomes a standby current value at a temperature (for example, 25° C.) that guarantees the standard value of the semiconductor memory device. The method for correcting the measured values will be described later. Then, the corrected measurement value and the determination value are compared. As a result of this comparison, if the measured value is smaller than the determination value, the semiconductor memory device under test is determined to be a good product, and if it is larger than the determination value, it is determined to be a defective product.

Next, an example of a method of correcting the measured value of the standby current mentioned above will be explained. Generally, standby current Isb of a semiconductor memory device can be expressed by the following equation.

[0014]

[Math 1]

Here, g and h are values specific to the semiconductor memory device, and T is the environmental temperature during the test. h is a value indicating the ratio between the environmental temperature T and the standby current Isb, and is a substantially constant value for semiconductor memory devices of the same type. This value of h is determined by measurement in advance. The standby current is Isb under the actual test environment temperature Tx.
x, the g of the semiconductor memory device under test is
The value of can be calculated using the following formula.

[0016]

[Math 2]

Therefore, the standby current of this semiconductor memory device under test at an environmental temperature Ty can be determined by substituting the equation 2 into the equation 1, and the following formula calculates the standby current at an environmental temperature Tx. This is a mathematical formula that converts to standby current at temperature Ty.

[0018]

[Math 3]

A procedure for determining whether a semiconductor memory device has a standby current temperature characteristic shown by the solid line 1 in FIG. 2 as a good product or a defective product using the above test procedure and measurement correction method will be described. Assuming that the environmental temperature is, for example, 27° C., the measured value of the standby current at that time is b. Therefore, we calculated the measured value b by the number 3 as if it were measured at 25℃.
is used to correct the standby current value at 25°C. The correction value c is determined by the following formula. Here, T25 is 25℃,
T27 represents 27°C.

[0020]

[Math 4]

A dashed-dotted line 2 in FIG. 2 is the temperature characteristic after correction obtained using Equation 3. When the environmental temperature during the test is 27°C, the measured value of the semiconductor memory device under test is b, and as explained in the prior art, the solid line 1 indicating the temperature characteristics before correction is a larger value than the judgment value A. Therefore, the semiconductor memory device under test is determined to be a defective product.

On the other hand, in the corrected dot-dash line 2, the measured value b on the solid line 1 has been corrected to the measured value c, so that the semiconductor memory device under test is determined to be a good product.

As described above, in the present invention, when the temperature environment during testing changes and the standby current of the semiconductor device under test changes, this standby current is corrected as a function of temperature to maintain a fixed temperature environment. Correct to the value below. Further, the corrected current value and the determination value are compared to determine the quality. Therefore, it is possible to prevent a product that should be determined to be a good product from being determined to be a defective product and a product that should be determined to be a defective product to be determined to be a good product due to fluctuations in the standby current caused by changes in the temperature environment.

[0024] If the environmental temperature during the test changes within a narrow temperature fluctuation range of about ±5°C, the standby current Isb
can be approximated as being proportional to the temperature T, so equation 5 can be used instead of equation 1.

[0025]

[Math 5]

Here, d and f are values specific to a semiconductor memory device, and are approximately constant values for semiconductor memory devices of the same type. The standby current is I under the environmental temperature Tx
When sbx is measured, the formula for correcting it to the standby current value c at 25° C. can be determined by the following formula.

[0027]

[Math 6]

Note that the value of d is determined by measurement in advance. The measured value may be corrected using this formula.

Furthermore, in this embodiment, a case has been described in which the measured value is corrected to determine whether the product is good or defective, but the determination value may be corrected to determine whether the product is good or defective. This correction of the determination value can be performed by giving the determination value a temperature characteristic similar to that of the standby current. For example, the judgment value A at an environmental temperature of 25°C
A formula for correcting A25 to the determination value A27 at an environmental temperature of 27° C. can be determined by the following formula.

[0030]

[Math 7]

[0031]

[Effects of the Invention] As described above, according to the first invention, the electrical characteristic values of the semiconductor device under test are measured and the measured values are compared with judgment values under a predetermined temperature environment. In a semiconductor testing method for determining pass/fail, there is a step of measuring the test environment temperature of the semiconductor device under test, and prior to the determination, the measured values of the electrical characteristics are determined in advance based on the measured value of the test environment temperature. According to the second invention, a step of correcting the measured value in a temperature environment is provided.
In a semiconductor testing method in which the electrical characteristic values of a semiconductor device under test are measured and the measured values are compared with judgment values to determine pass/fail, there are a step of measuring the test environment temperature of the semiconductor device under test, and prior to judgment. , the step of correcting the judgment value based on the measured value of the test environment temperature, it is possible to eliminate the influence of fluctuations in the test environment temperature on the pass/fail judgment, and it is possible to correctly judge the pass/fail judgment of the semiconductor device under test. The effect is that it can be done.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a test procedure for a semiconductor memory device according to the present invention.

FIG. 2 is a diagram showing an example of temperature characteristics of standby current of a semiconductor memory device.

FIG. 3 is a flowchart showing a procedure for testing a semiconductor memory device using a conventional semiconductor testing device.

[Explanation of symbols]

Claims (2)

[Claims] 1. A semiconductor testing method in which the electrical characteristic values of a semiconductor device under test are measured and the measured values are compared with judgment values under a predetermined temperature environment to determine pass/fail. a step of measuring a test environment temperature of the semiconductor device under test; and prior to the determination, measuring the measured value of the electrical characteristic under the predetermined temperature environment based on the measured value of the test environment temperature; A semiconductor testing method comprising a step of correcting the value. 2. A semiconductor testing method that measures electrical characteristic values of a semiconductor device under test and compares the measured values with judgment values to determine pass/fail, the method comprising: controlling the test environment temperature of the semiconductor device under test; a step of measuring, and prior to the determination,
A semiconductor testing method comprising: correcting the determination value based on the measured value of the test environment temperature.