Patent Publication Number: US-2023160754-A1

Title: Semiconductor device and trimming method of the same

Description:
BACKGROUND 
     The present disclosure relates to a semiconductor device and a trimming method of the semiconductor device having a temperature sensor circuit. 
     A semiconductor device having a temperature sensor module is disclosed in U.S. Patent Application Publication No. 2017/315001, for example. U.S. Patent Application Publication No. 2017/315001 discloses a semiconductor device capable of measuring temperature and power supply voltage with high accuracy. 
     SUMMARY 
     Recently, a severe condition for the accuracy of the temperature sensor incorporated in the semiconductor device (error tolerance) is required. In addition, the self-heating due to the high functionality of the semiconductor device (increase in power consumption) affects the yield of the semiconductor device. For example, the self-heating of the semiconductor device cause to rise the temperature to be detected by the temperature sensor in the semiconductor device, so that the temperature of the semiconductor device may be higher than the measurement environment temperature. The detection result of the temperature sensor is affected by manufacturing variations of the device. In order to correct variations in the detection results due to manufacturing variations, the temperature sensor is tested. The output of the temperature sensor is corrected based on the temperature of test measurement environment and the detection result of the temperature sensor under test measurement environment. However, when there is a difference between the temperature of the test measurement environment and an actual temperature of the semiconductor device, it is difficult to appropriately correct variations of the output of the temperature sensor. 
     The self-heating of the semiconductor device also affects the adjacent semiconductor device. Therefore, the difference between the actual temperature of the semiconductor device and the temperature of measurement environment is different for each semiconductor device. 
     The output of the temperature sensor is to be corrected appropriately even if the semiconductor device is self-heated. 
     Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. 
     An outline of representative ones of the present disclosure will be briefly described below. 
     According to an embodiment, a semiconductor device includes a semiconductor substrate on which a temperature sensor is formed, a plurality of insulating films formed above the semiconductor substrate, a temperature measurement wiring pattern formed on a first insulating film which is one of the plurality of the insulating films, a detection electrode which is formed on the uppermost insulating film of the plurality of the insulating films to be arranged at a position corresponding to the first temperature measurement wiring pattern and is provided for contact a temperature measurement needle, and one or more via electrodes formed in one or more insulating film between the temperature measurement electrode and the detection electrode to couple between the temperature measurement electrode and the detection electrode. 
     In another embodiment, a trimming method includes contacting the detection electrode with the temperature measurement needle, measuring a temperature in vicinity of the temperature sensor through the detection electrode after supplying a power to the semiconductor device, acquiring a code output by the temperature sensor, trimming a code to be output as an internal temperature of the semiconductor device based on the measured temperature through the detection electrode and the acquired code. 
     According to the semiconductor device of the above embodiment, the temperature sensor can be appropriately corrected by actually measuring the internal temperature of the semiconductor device and using the measured internal temperature as a reference. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a conceptual diagram showing probe needles for temperature measurement and a cross-sectional view of the semiconductor device according to the first embodiment. 
         FIG.  2    is a conceptual plane view of the semiconductor device according to the first embodiment. 
         FIG.  3    is a process flow diagram showing the trimming method of the temperature sensor according to the first embodiment. 
         FIG.  4    is a diagram illustrating a trimming method. 
         FIG.  5    is a conceptual diagram showing a case where a heat absorbing block is provided on the needle for temperature measurement according to the second embodiment. 
         FIG.  6    is a diagram illustrating a temperature gradient image and a temperature gradient suppression image in the device. 
         FIG.  7    is a diagram showing a trimming method of the temperature sensor according to the third embodiment. 
         FIG.  8    is a processing flow diagram showing a trimming method of the temperature sensor according to the fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, Embodiment(s) will be described with reference to the drawings. However, in the following description, the same components are denoted by the same reference numerals, and a repetitive description thereof may be omitted. It should be noted that the drawings may be represented schematically in comparison with actual embodiments for the sake of clarity of explanation, but are merely an example and do not limit the interpretation of the present disclosure. 
       FIG.  1    is a conceptual diagram showing probe needles for temperature measurement and a cross-sectional view of the semiconductor device according to the first embodiment.  FIG.  2    is a conceptual plane view of the semiconductor device according to the first embodiment.  FIG.  3    is a process flow diagram showing the trimming method of the temperature sensor according to the first embodiment.  FIG.  4    is a diagram illustrating a trimming method. 
     In the development and manufacturing process of semiconductor device, wafer prober apparatus is used in the electrical inspection of semiconductor wafers. In electrical inspection, test signals are given to individual devices (semiconductor chips) on the semiconductor wafer from a measuring instrument or a tester through a probe needle or a probe card to acquire response signals from the device. For example, the wafer prober apparatus is used to transport semiconductor wafers and to contact probe needles or probe cards at predetermined position on individual devices on the semiconductor wafer. 
     For example, when the output of the temperature sensor in the semiconductor device is corrected based on the set temperature of the wafer prober apparatus (hereinafter, “Tex”), it is preferable to make a state that the internal temperature of the semiconductor device (hereinafter “Tin”) is equal to Tex in the test of the temperature sensor. To achieve this, we have considered measures to prevent self-heating in the test process such as a test flow with pre-heating. The pre-heating is performed at the beginning of the entire test. On the basis of Tex and the output results of the temperature sensor under such a test environment, trimming for correction of the output of the temperature sensor is performed. In this way, the output variation of the temperature sensor is adjusted to achieve high accuracy. 
     However, the self-heating of the device may cause a difference between Tex and Tin. Further, in the semiconductor device having a plurality of temperature sensors, each temperature sensor is affected from (power consumption of) the peripheral circuit. A temperature difference occurs even inside one semiconductor device, and the temperature sensors in the same semiconductor device detect respective different temperature. In this state, assuming Tin≈Tex, when performing the trimming of the temperature sensor, the accuracy of the temperature detection of the temperature sensor is lowered. Further, originally, despite a temperature sensor that detects the internal temperature appropriately, since the output result is out of the trimmable range, it may be determined as defective as not satisfy the required accuracy of the temperature sensor. That is, there is a possibility that the yield is lowered. 
     Therefore, in the first embodiment, as shown in  FIG.  1   , providing temperature detection electrodes TSE 1 , TSE 2 , TSE 3 , TSE 4  exposed to the device surface. The temperature detection electrodes TSE 1  to TSE 4  are formed in the same layer as the bonding electrode. The temperature detection electrodes TSE 1 , TSE 2 , TSE 3 , TSE 4  are connected to the wiring patterns L 1 T, L 2 T, L 3 T, L 4 T which are formed in the different wiring layers through the respective one or more metal via electrodes VA 1 , VA 2 , VA 3 , VA 4 . Thus, the respective temperatures of the different wiring patterns L 1 T, L 2 T, L 3 T, L 4 T, it is possible to directly monitor via the temperature measurement needles Tmeas 1 , Tmeas 2 , Tmeas 3 , Tmeas 4  which are physically contacted to the temperature detection electrodes TSE 1 , TSE 2 , TSE 3 , TSE 4 . The temperature measurement needles Tmeas 1 , Tmeas 2 , Tmeas 3 , Tmeas 4  are provided on the probe needle or probe card of the wafer prober apparatus. Incidentally, the wiring patterns L 1 T, L 2 T, L 3 T, L 4 T are not electrically connected to the internal circuits of the semiconductor device. In other words, the wiring patterns L 1 T, L 2 T, L 3 T, L 4 T can be referred to as temperature measurement wiring patterns which are exclusively arranged for measuring the internal temperature Tin. 
     The temperature directly monitored by the temperature measurement needles Tmeas 1 , Tmeas 2 , Tmeas 3 , Tmeas 4  is defined as the internal temperature of the semiconductor device (Tin). Accordingly, the trimming of the temperature sensor can be performed by using the directly monitored internal temperature Tin which is directly monitored by the temperature measurement needles T, not by using the set temperature (Tex) of the wafer prober apparatus. This makes it possible to reduce the error due to the temperature discrepancy (deviation) between Tex and Tin. 
     The via electrodes VA 1 , VA 2 , VA 3 , VA 4 , for example, may be a metal electrode such as aluminum (Al). The thermal conductivity of aluminum (Al) is 240 w/m·k, and it is possible to measure temperature with about 200 times accuracy than the thermal conductivity 1.4 w/m·k of silicon oxide is an insulating film. Metals such as aluminum are suitable as materials for the via electrodes VA 1 , VA 2 , VA 3 , VA 4 . 
     In  FIG.  1   , for example, the surface portion of the semiconductor substrate SUB composed of silicon single crystal, a plurality of semiconductor elements including the temperature sensor (temperature sensor circuit) TSN are formed. The temperature sensor TSN includes circuits such as a bandgap reference circuit BGR and an analog-to-digital conversion circuit ADC. 
     On the upper side of the surface portion of the semiconductor substrate SUB, for example, a plurality of insulating films INS 1 , INS 2 , INS 3 , INS 4 , INS 5 , INS 6  composed of a silicon oxide film or the like are laminated in this order. The wiring patterns L 4 , L 4 T are formed on the upper side of the first insulating film INS 1 , the via electrode VA 4  is formed by embedding in a through hole formed in the second insulating film INS 2 . The wiring pattern L 3 T are formed on the upper side of the insulating film INS 2 , the via electrode VA 3  is formed by embedding in a through hole formed in the third insulating film INS 3 . The wiring pattern L 2 , L 2 T are formed on the upper side of the insulating film INS 3 , the via electrode VA 2  is formed by embedding in a through hole formed in the fourth insulating film INS 4 . The wiring pattern L 1 , L 1 T are formed on the upper side of the insulating film INS 4 , the via electrode VA 1  is formed by embedding in the through hole formed in the fifth insulating film INS 5 . Each of the temperature detection electrodes TSE 1 , TSE 2 , TSE 3 , TSE 4  is connected to the via electrode VA 1 , each of the temperature detection electrodes TSE 1 , TSE 2 , TSE 3 , TSE 4  is formed by embedding in a through hole formed in the sixth insulating film INS 6 . In the present embodiment, the sixth insulating film INS 6  can also be referred to as the uppermost insulating film. 
     Thus, as shown in  FIG.  1   , the temperature measurement needle Tmeas 1  contacts with the wiring pattern LiT via the via electrode VA 1 . The temperature measurement needle Tmeas 2  contacts with the wiring pattern L 2 T via the via electrodes VA 1 , VA 2 . The temperature measurement needle Tmeas 3  contacts with the wiring pattern L 3 T via the via electrodes VA 1 , VA 2 , VA 3 . The temperature measurement needle Tmeas 4  contacts the wiring pattern L 4 T with via the via electrodes VA 1 , VA 2 , VA 3 , VA 4 . 
     In  FIG.  1   , the temperature detection electrode TSE 1  and the wiring pattern L 1 T are connected at the shortest distance via the via electrode VA 1 . Similarly, the temperature detection electrode TSE 2  and the wiring pattern L 2 T is connected at the shortest distance via the via electrodes VA 1 , VA 2 , the temperature detection electrode TSE 3  and the wiring pattern L 3 T is connected at the shortest distance via the via electrodes VA 1 , VA 2 , VA 3 , the temperature detection electrode TSE 4  and the wiring pattern L 4 T is connected at the shortest distance via the via electrodes VA 1 , VA 2 , VA 3 , VA 4 . That is, in plane view as viewed from above, the via electrode VA 1  connected to the wiring pattern L 1 T is provided directly below the temperature detection electrode TSE 1 . Similarly, the via electrodes VA 1 , VA 2  between the wiring pattern L 2 T and the temperature detection electrode TSE 2  are provided directly below the temperature detection electrode TSE 2 . The via electrodes VA 1 , VA 2 , VA 3  between the wiring pattern L 3 T and the temperature detection electrode TSE 3  is provided directly below the temperature detection electrode TSE 3 . The via electrodes VA 1 , VA 2 , VA 3 , VA 4  between the wiring pattern L 4 T is provided directly below the temperature detection electrode TSE 4 . As a result, accurate temperatures of the wiring patterns L 1 T, L 2 T, L 3 T, and L 4 T can be measured through the temperature measurement needles Tmeas 1 , Tmeas 2 , Tmeas 3  and Tmeas 4 . 
     Incidentally, the via electrodes VA 1 , VA 2 , VA 3 , VA 4  and the wiring patterns L 1 T, L 2 T, L 3 T, L 4 T are not via electrodes and wiring layers provided newly for temperature measurement. The via electrodes VA 1 , VA 2 , VA 3 , VA 4  and wiring layers for the wiring patterns L 1 T, L 2 T, L 3 T, L 4 T are also used as via electrodes and wiring layers for forming the central processing unit CPU, memory MEM, peripheral circuit PER (see  FIG.  2   ) in the semiconductor device. That is, the configuration shown in  FIG.  1    can be realized without the addition of a new manufacturing process. 
       FIG.  2    is a plan view showing a conceptual layout configuration of semiconductor device ICs having a plurality of temperature sensors TSN to TSN 4 , central processing units CPUs, memory devices MEMs, and peripheral circuits PERs. Further, in  FIG.  2   , the circuit configuration of the temperature sensor TSNi (i=1 to 4) is shown. The temperature sensor TSNi includes a is bandgap reference circuit BGR for outputting a voltage Vs depending on the temperature, the voltage Vs receives the voltage Vs, and an analog-to-digital converter ADC for receiving the voltage Vs and converting the voltage Vs into the code signal Code as a digital signal indicating the temperature. 
     The semiconductor device IC is a rectangular semiconductor chip CHIP. In this example, a plurality of temperature sensors TSN 1  to TSN 4  are respectively disposed in the vicinity of the four corners of the semiconductor chip CHIP. 
     As shown in  FIG.  2   , around the forming area of the temperature sensor TSN 1 , four temperature detection electrodes TSE are arranged. Here, the four temperature detection electrodes TSE corresponds to the temperature detection electrodes TSE 1 , TSE 2 , TSE 3 , TSE 4  of  FIG.  1   . In lower layers of the temperature detection electrodes TSE 1 , TSE 2 , TSE 3 , TSE 4 , as described in  FIG.  1   , the via electrodes VA 1 , VA 2 , VA 3 , VA 4  and the wiring patterns L 1 T, L 2 T, L 3 T, L 4 T are provided. 
     In the two surrounding areas of the forming area of the temperature sensor TSN 2 , four temperature detection electrodes TSEs (TSE 1 , TSE 2 , TSE 3 , TSE 4 ) are arranged two by two. Around the forming area of the temperature sensor TSN 3 , four temperature detection electrodes TSE (TSE 1 , TSE 2 , TSE 3 , TSE 4 ) are arranged collectively. As in the temperature sensors TSN 1  to TSN 3 , by placing the temperature detection electrodes TSE in the surrounding area of the formation area of the temperature sensor TSN, it is possible to accurately measure the internal temperature Tin in the vicinity of the forming area of the temperature sensors TSN 1  to TSN 3 . 
     At least one of the four temperature detection electrodes TSE (TSE 1 , TSE 2 , TSE 3 , TSE 4 ) may be arranged on the forming area of the temperature sensor such as temperature detection electrode for the temperature sensor TSN 4 . For example, one temperature detection electrode TSE may be arranged in the vicinity (or upper side) of the output circuit for outputting voltage Vs of the bandgap reference circuit BGR of the temperature sensor TSN 4 . Thus, it may be configured to be able to accurately measure the internal temperature Tin in the vicinity of the output circuit of the bandgap reference circuit BGR. The other three temperature detection electrodes TSE may be arranged in two surrounding areas of the forming area of the temperature sensor TSN 4 . For example, the lowermost wiring pattern L 4 T connected to the temperature detection electrode TSE 4  of  FIG.  1    may be arranged in the vicinity (or the upper) of the output circuit of the bandgap reference circuit BGR. The wiring patterns L 1 T, L 2 T, L 3 T connected with the temperature detection electrodes TSE 1 , TSE 2 , TSE 3  of  FIG.  1    respectively, may be arranged in two surrounding areas of the formation area of the temperature sensor TSN 4 . The wiring patterns L 1 T, L 2 T, L 3 T, as compared with the wiring pattern L 4 T, can be said to be a wiring pattern provided on the upper layer. 
     Next, a trimming method of the temperature sensor according to the first embodiment will be described with reference to  FIG.  3   . 
     Step S1) Set the set temperature of the wafer prober apparatus. The set temperature at this time is referred to as an external temperature Tex. 
     Step S2 (pre-heat)): The probe card is warmed up for a certain period of time to align the chuck temperature and device temperature conditions (Tex≈Tin). 
     Step S3) The power voltage is supplied to the device. As a result, the semiconductor chip, which is a device, generates heat (Tex is no longer equal to Tin). 
     Step SA) By the configuration described in  FIG.  1   , the internal temperature (TinA) of the device is measured via the temperature measurement needle Tmeas (measurement temperature by Tmes=TinA). There is no particular problem when the four internal temperatures Tin measured by the temperature measurement needle Tmeas 1 , Tmeas 2 , Tmeas 3 , Tmeas 4  of  FIG.  1    are the same. However, when the four measured internal temperatures Tin are different each other, the calculated value by calculating the average of the four internal temperatures Tin or by calculating the weighted average may be the internal temperature TinA. 
     Step S4) The test of the temperature sensor circuit TSN is tested at the above temperature. In this test, the code from the analog-to-digital conversion circuit ADC in the temperature sensor circuit TSN is acquired. 
     Step SB) After the measurement of S4, the internal temperature (TinB) of the device is measured again via the temperature measurement needle Tmeas for temperature measurement (measurement temperature by Tmes=TinB). There is no particular problem if the four internal temperatures Tin measured by the temperature measurement needle Tmeas 1 , Tmeas 2 , Tmeas 3 , Tmeas 4  of  FIG.  1    are the same. However, when the four internal temperatures Tin measured by the temperature measurement needles are different each other, the calculated value by calculating the average of the four internal temperatures Tin or by calculating the weighted average may be the internal temperature TinB. Then, the internal temperature Tin is calculated based on the internal temperature TinA and TinB at the time of measurement (or calculated). There are no particular problems if TinA and TinB are the same. However, if TinA and TinB are different each other, for example, the averaged value of TinA and TinB may be the final internal temperature Tin. 
     Step S5) The power voltage to the device is stopped. Heat generation of semiconductor chip, which is device, stops. 
     Step S6) Based on the final internal temperature Tin calculated in step SB, trimming process of the output code of the temperature sensor TSN is performed. 
     Step S7) If there are a plurality of devices in the wafer is that have not yet been trimmed, the process returns to step S1 to execute the processing flow. Once the temperature sensor circuit TSN of all devices in the wafer has been tested, the process flow is terminated. 
     The output code of the temperature sensor circuit TSN, in the above-described procedure, may be trimmed by three times test of the temperature sensor circuit at the external temperature Tex set to −41° C., room temperature (e.g., 25° C.), and 126° C. 
     In the trimming method described above, the internal temperature Tin of the device is measured in step SA and step SB, but step SB may be omitted. 
     An example of a method for trimming the code of the temperature sensor TSN will be described with reference to  FIG.  4   . In the example of  FIG.  4   , three times tests are performed with the external temperature Tex set at −41° C., room temperature (e.g., 25° C.) and 126° C. By the tests, the internal temperatures Tin measured via the temperature measurement needle indicates −40° C. at Tex=−41° C., 26° C. at Tex=25° C. and 127° C. at Tex=126° C. At this time, the code of the output of the temperature sensor TSN is, for example, THCODE_L at an internal temperature Tin of −40° C., THCODE_T at an internal temperature Tin of 26° C., and THCODE_H at an internal temperature Tin of 127° C. Here, data indicating the correspondence relationship between the internal temperature Tin and the output code of the temperature sensor TSN is stored in the memory device MEM provided in the semiconductor device IC. The output of the temperature sensor may be trimmed by using the stored data. For example, the offset of the output of the temperature sensor may be adjusted based on the stored data. Preferably, a non-volatile storage device, such as an electric fuse (eFuse) in the semiconductor device IC, may store data indicating a correspondence between the output code of the internal temperature Tin and the temperature sensor TSN. 
     According to the first embodiment, the device internal temperature Tin in the vicinity of the temperature sensor TSN is actually measured before the semiconductor device is mounted on the printed board. Then, the output code of the temperature sensor TSN are trimmed based on the internal temperature Tin actually measured. Thus, it is possible to trim the temperature sensor TSN appropriately, and to improve the accuracy of the temperature sensor TSN. 
     Further, the temperature sensor can correctly evaluate whether it detects the temperature appropriately or whether it can be trimmed. Thus, it is possible to prevent the yield deterioration due to being determined to be defective despite the originally good product. 
     Second Embodiment 
       FIG.  5    is a conceptual diagram showing a case where the heat absorbing block HAB is provided on the needle for the temperature measurement according to the second embodiment.  FIG.  6    is a is diagram illustrating a temperature gradient image and a temperature gradient suppression image in the device. 
     In the first embodiment, when mounting a plurality of temperature sensors TSN 1  to TSN 4  in the same semiconductor device, each temperature sensor is affected from the peripheral circuits (for example, effect of power consumption of the peripheral circuits). The temperature difference of inside of the semiconductor device occurs, thus, each of the temperature sensors TSN 1  to TSN 4  may detect respective different internal temperature Tin even in the same device. 
     In the present embodiment, a method of making the temperature of the entire inside of the chip uniform is disclosed. As shown in  FIG.  5   , in the probe needle and the probe card of the wafer prober apparatus, heat absorbing blocks HABs are provided on the needle or on base sides of the temperature measurement needle Tmeas 1 , Tmeas 2 , Tmeas 3 , Tmeas 4 . By providing the heat absorption block HAB, the heat generated inside the device is absorbed by the heat absorption block HAB to radiate heat, thereby realizing uniform temperature in the device. The heat absorbing block HAB may be provided with a through hole TH through which a probe needle for measuring a signal passes. 
     In the graph of  FIG.  6   , the vertical axis represents the internal temperature Tin (° C.), the horizontal axis represents the temperature measuring point MP (TSE 1  to TSE 4 : see  FIG.  1   ). In  FIG.  6   , the line TL 1  indicates the temperature gradient at the temperature measuring point MP when the heat absorbing block HAB is not provided (NHAB). Line TL 2  shows the temperature gradient at the temperature measuring points when the heat absorbing block HAB are provided. Thus, by providing the heat absorbing block HAB, it is possible to equalize the temperature gradient of the internal temperature Tin in the device. The configuration of the heat absorbing block HAB is provided for each temperature measurement needle Tmeas 1  to Tmeas 4  of the temperature sensor TSN 1  to TSN 4  of  FIG.  2   . Thus, it is possible to uniformize by suppressing the temperature gradient of the internal temperatures Tin of each temperature sensor TSN 1  to TSN 4  in the same device. 
     By equalizing the internal temperatures Tin in the device, the internal temperatures Tin of each temperature sensor TSN 1  to TSN 4  can be substantially the same. 
     This eliminates the need to acquire codes for each temperature sensor TSN 1  to TSN 4  eliminating the need for complex calculations within the temperature trimming program. As a result, it is expected that the efficiency of the program coding and the shortening of the test time are realized. 
     Further, the temperature in the device becomes uniform, it is possible to more accurately grasp whether the code value when actually measured at a number of times, it is possible to eliminate the distribution deviation due to the temperature difference inside the device. Further, in the probe card, the is free space reserved for avoiding the thermal influence of the adjacent chip is not necessary, and the effect of the compact design of the probe card, e.g., inexpensive and increase of the number of measurements at the same time, is expected. 
     Third Embodiment 
     The third embodiment will be described with reference to  FIG.  7   .  FIG.  7    is a diagram showing a trimming method of the temperature sensor according to the third embodiment. 
     In  FIG.  7   , the internal temperature Tin of the device, which is measured through the temperature detection electrode and the temperature measurement needle as the first embodiment, is captured at a predetermined intervals and stored in the server in parallel with the normal test. That is, as shown in Step1 of  FIG.  7   , the internal temperatures of the devices to be tested (chip 1 -chipn) in the semiconductor wafer are captured at 10 msec intervals from the start of the test. The captured internal temperatures of the devices to be tested (chip 1 -chipn) are stored in the server. As shown as an Step2 of  FIG.  7   , a normal test (including a temperature sensor test) is performed on the device to be tested (chip 1 -chipn) in the semiconductor wafer. Here, Step1 and Step2 are performed in parallel. 
     Since Step2 can calculate the time from the test start to the temperature sensor test, Step1 and Step2 make it clear the internal temperature Tin of each chip when performing the temperature sensor test. 
     Although the tests of the devices chip 1  to chipn is performed separately, the internal temperature Tin of the device is accurately known when the temperature sensor test of the respective devices is performed. Thus, the code of the temperature sensor TSN in each device is trimmed with reference to the captured internal temperature Tin. Even if there is a difference in the internal temperature Tin between the devices, if the internal temperature Tin of the individual devices is accurately known, it is possible to accurately trim the code of the temperature sensor. 
     That is, in the third embodiment, by capturing and storing the internal temperature Tin of the device at the predetermined intervals in parallel with the normal test, the internal temperature Tin of each test item of the devices can be confirmed. After completion of the test, the internal temperatures Tin at the test of the temperature sensor of all devices can be acquired based on the time from the test start to the test of the temperature sensor TSN. Thus, it is possible to perform separately trimming process of the code of the temperature sensor based on captured internal temperature Tin at the test of the temperature sensor of each device. Accordingly, the program for trimming the temperature becomes complicated calculation is not necessary, it can be expected to improve the efficiency of the program coding and the yield of the semiconductor chip. 
     Fourth Embodiment 
     As an application example of the third embodiment, a trimming method will be described in which, after an accurate internal temperature Tin is acquired, all data of the internal temperature Tin is stored in a server, and trimming of a temperature sensor circuit incorporated in a semiconductor device is performed by using data stored in the server.  FIG.  8    is a processing flow diagram showing a trimming method of the temperature sensor circuit according to the fourth embodiment. Hereinafter, the processing flow diagram of  FIG.  8    will be described. Steps S 11 , S 14  to S 17  are processes performed by the tester TST, and steps S 12  and S 13  are processes performed by the server SRV. 
     Step S 11 : A plurality of areas on the semiconductor wafer WF to be measured, for example, five semiconductor devices (chips) arranged at five points (A, B, C, D, E) are performed the test described in  FIG.  7   . That is, as described in the third embodiment, the internal temperatures Tin of the five semiconductor devices are acquired at the predetermined intervals in parallel with the normal test. The acquired information is transferred to the server SRV and stored in the server SRV. Thus, the internal temperature Tin for each test item of the five semiconductor devices can be confirmed. 
     Step S 12  (compare with past data): In the server SRV, the internal temperature Tin for each test item of the five semiconductor devices acquired in step S 11  are compared with the measured data information of the internal temperature Tin for is each test item of the same product of the semiconductor device executed in the past 
     Step S 13  (narrowing of the optimum conditions): The wafer test environment and the Tin value that fluctuates in the wafer plane are estimated by using the information of the wafer stored in the past in the server with the highest correlation with the information tested (temperature measurement) on the semiconductor chip corresponding to multiple areas (A-E). Then, the optimum test conditions for each test item is set based on the estimated value of the internal temperature Tin. 
     Step S 14  (test program setting): The tester TST reflects the optimum test conditions obtained in step S 13  to the configuration information of the temperature distribution estimation test program in the plane of the semiconductor wafer WF to be measured. 
     Step S 15  (test start): The tester TST executes the test program obtained in step S 14  to start the test of the semiconductor wafer WF to be measured. 
     Step S 16  (execution of each test and measurement of temperature): The test is performed under appropriate conditions in consideration of heat generation by each test item. At the same time, temperature measurement is performed at all times. It is checked there is no difference between the test temperature for which the test conditions were determined and the actual temperature conditions. If there is difference between test conditions or dependent on the test temperature, the test is performed again. When there is no difference between the test temperature and the actual temperature conditions for which the test conditions were determined, the trimming of the temperature sensor TSN in each chip of the semiconductor wafer WF to be measured is performed based on the measurement data information of the internal temperature Tin in the past. 
     Step S 17  (test end and the next device): When the test of all devices of the semiconductor wafer WF to be measured is completed, the test ends. If the test of all devices of the semiconductor wafer WF to be measured has not been completed, the test of the next device (next chip) is performed. 
     Thus, the test of the semiconductor chip corresponding to the plurality of areas (A to E) in the plane of the measurement target wafer WF is performed, and the result is compared with the past wafer measurement data of the server SRV. The wafer test environment and the Tin value that fluctuates in the wafer plane are estimated by using the information of the wafer stored in the past in the server with the highest correlation with the information tested (temperature measurement) on the semiconductor chip corresponding to multiple areas (A-E). The optimum test conditions for each test item is set based on the estimated value of the internal temperature Tin. The DUTs (semiconductor chips) other than DUTs (semiconductor chips corresponding to multiple areas (A to E)) measured at the start of the test are also constantly measured in temperature to compare the estimated and measured values. As a result, since appropriate test points can be set in each test item, it is possible to prevent yield reduction of the semiconductor device due to improved quality and overkill. 
     While the invention made by the present inventor has been specifically described above based on the Embodiment, the present invention is not limited to the above-described embodiment and Embodiment, and it is needless to say that the present invention can be variously modified.