[發明所欲解決之問題] 然而，於專利文獻1所記載之方法中，記載為將規定之測定次數設定為M次，於未檢測到測定異常且測定值之變動較少時，可於達到該M次前結束測定處理，但於該情形時，若未連續N次滿足測定值落在容許範圍內之條件，則亦無法結束測定處理。 本發明係鑒於如上所述之情況而完成者，其目的在於減少電路基板之導體圖案與檢查探針之接觸狀態之影響，並且快速地進行檢查。 [解決問題之技術手段] 本發明之基板檢查方法係對基於經由檢查探針而流動至形成於電路基板之導體圖案之電流的電特性值進行測定，且基於該電特性值之測定值判定上述電路基板是否良好者，於第1次之測定值偏離容許範圍之情形時，改變對於上述檢查探針之電流之方向而進行第2次測定，於該第2次之測定值偏離上述容許範圍之情形時，以測定出上述第1次之測定值與上述第2次之測定值中的偏離上述容許範圍之差之值較小之測定值時之電流方向，進行第3次以後之測定。又，本發明之基板檢查裝置係對基於流動於形成於電路基板之導體圖案之電流的電特性值進行測定，且基於該電特性值之測定值判定上述電路基板是否良好者，且具備：一對檢查探針，其等與上述導體圖案接觸；切換機構，其用以切換流通於上述檢查探針間之電流之方向；檢查判定部，其將上述測定值與預先規定之臨限值進行比較，於上述測定值為容許範圍內之情形時，將上述電路基板判定為良好；及電流方向控制部，其於第1次之測定值未由上述檢查判定部判定為良好之情形時，以改變對於上述檢查探針之電流之方向之方式對上述切換機構進行控制，於第2次之測定值未由上述檢查判定部判定為良好之情形時，以設為測定出上述第1次之測定值與上述第2次之測定值中的偏離上述容許範圍之差之值較小之測定值時之電流之方向的方式對上述切換機構進行控制。於因檢查探針之接觸不良等而導致測定值偏離容許範圍之情形時，亦可藉由進行2次以上之測定，使接觸狀態之影響變小而進行準確之檢查。而且，於測定值成為容許範圍內時，將該電路基板判定為良好。又，於進行複數次測定之情形時，若改變電流之方向而進行第1次測定與第2次測定，則其測定值產生差。認為其原因在於，使檢查探針與導體圖案接觸之狀態下之電路徑係混合存在有導體與絕緣體(例如接觸部)，而容易於任一方向上流通電流。又，若反覆進行測定，則隨著增多測定次數而測定值逐漸收斂成特定值。因此，若一面交替地切換電流之方向一面進行測定，則測定值逐漸收斂成特定值，但交替地測定到較大之測定值與較小之測定值。一面交替地進行切換一面進行之該測定係於測定值進入容許範圍內之前需要時間。於本發明中，將最初之2次之測定值進行比較並以測定出偏離容許範圍之差之值較小之測定值時的電流之方向進行第3次之後之測定，藉此，以接觸狀態之影響更小之測定條件進行測定，從而可更準確且快速地到達容許範圍內，相應地，可縮短檢查時間。本發明之基板檢查方法亦可設為如下，即，於上述測定值為上述容許範圍內之情形時判定為良好，於未判定為良好之情形時，反覆進行測定，於測定次數已達到上限之情形時判定為不良。又，本發明之基板檢查裝置亦可具備：條件設定部，其設定測定次數之上限；及反覆控制部，其於未由上述檢查判定部判定為良好之情形時，反覆進行測定直至上述測定次數達到上限為止；且上述檢查判定部於未判定為良好而上述測定次數已達到上限之情形時，判定為不良。[發明之效果]根據本發明，可減少電路基板之導體圖案與檢查探針之接觸狀態之影響，並且快速地進行檢查。[Problems to be Solved by the Invention] However, in the method described in Patent Document 1, it is described that the predetermined number of times of measurement is set to M times, and when the measurement abnormality is not detected and the variation of the measured value is small, it can be achieved. The measurement process is terminated before the M times. However, in this case, if the condition that the measured value falls within the allowable range is not continuously N times, the measurement process cannot be completed. The present invention has been made in view of the above circumstances, and an object thereof is to reduce the influence of the contact state between the conductor pattern of the circuit board and the inspection probe, and to perform inspection quickly. [Means for Solving the Problem] The substrate inspection method of the present invention measures an electrical characteristic value based on a current flowing through a test probe to a conductor pattern formed on a circuit board, and determines the above based on the measured value of the electrical characteristic value. Whether the circuit board is good or not, when the measured value of the first time deviates from the allowable range, the second measurement is performed by changing the direction of the current of the inspection probe, and the second measurement value deviates from the allowable range. In the case of the measurement, the third and subsequent measurements are performed by measuring the current direction when the measured value of the difference between the first measurement value and the second measurement value is smaller than the allowable range. Moreover, the substrate inspection apparatus of the present invention measures the electrical characteristic value based on the current flowing through the conductor pattern formed on the circuit board, and determines whether the circuit board is good based on the measured value of the electrical characteristic value, and includes: The inspection probe is in contact with the conductor pattern; the switching mechanism is configured to switch a direction of current flowing between the inspection probes; and the inspection determination unit compares the measured value with a predetermined threshold value When the measured value is within the allowable range, the circuit board is judged to be good; and the current direction control unit is changed when the first measured value is not determined to be good by the inspection determining unit. The switching mechanism is controlled to check the direction of the current of the probe, and when the second measurement value is not determined by the inspection determination unit, the first measurement value is measured. In the manner of the direction of the current at the measurement value which is smaller than the value of the difference between the above-mentioned allowable ranges in the second measurement value, the switching mechanism is Line control. When the measured value deviates from the allowable range due to contact failure of the inspection probe or the like, the measurement may be performed twice or more, and the influence of the contact state may be reduced to perform an accurate inspection. Further, when the measured value is within the allowable range, the circuit board is judged to be good. Further, when the measurement is performed plural times, when the first measurement and the second measurement are performed by changing the direction of the current, the measured value is inferior. The reason for this is considered to be that a conductor and an insulator (for example, a contact portion) are mixed in an electric path in a state in which the inspection probe is in contact with the conductor pattern, and current is likely to flow in either direction. Further, when the measurement is repeated, the measured value gradually converges to a specific value as the number of times of measurement increases. Therefore, when the measurement is performed while alternately switching the direction of the current, the measured value gradually converges to a specific value, but the larger measured value and the smaller measured value are alternately measured. This measurement is performed while alternately switching, and it takes time before the measured value enters the allowable range. In the present invention, the measurement is performed after the third time by comparing the measured values of the first two times and measuring the current in the case where the value of the difference from the allowable range is small, thereby taking the contact state. The measurement conditions having a smaller influence are measured, so that the allowable range can be reached more accurately and quickly, and accordingly, the inspection time can be shortened. The substrate inspection method of the present invention may be determined to be good when the measurement value is within the allowable range, and if it is not determined to be good, the measurement is repeated, and the number of times of measurement has reached the upper limit. In the case, it was judged to be bad. Further, the substrate inspecting apparatus of the present invention may further include: a condition setting unit that sets an upper limit of the number of times of measurement; and a reverse control unit that repeatedly measures the measurement until the number of times of measurement is not determined by the inspection determination unit. When the upper limit is reached, the inspection determination unit determines that the number of measurement times has reached the upper limit when it is not determined to be good. [Effects of the Invention] According to the present invention, it is possible to reduce the influence of the contact state between the conductor pattern of the circuit board and the inspection probe, and to perform inspection quickly.
以下，一面參照圖式，一面對本發明之實施形態進行說明。[基板檢查裝置]第1實施形態之基板檢查裝置11係對電路基板1之導體圖案2進行導通檢查者，如圖2所示，具備：直流電流源12，其產生特定之直流電流；一對檢查探針13，其等與露出於電路基板1上之導體圖案2之兩端部接觸；切換開關(切換機構)14，其設置於檢查探針13與直流電流源12之間；電位偵測部15，其用以偵測檢查探針13間之電位；控制部16，其控制對檢查探針13之通電並且對電路基板1是否良好進行判定；及顯示部17，其顯示其判定結果等。作為檢查探針13，例如使用二端子者，使每1根探針用針與導體圖案2接觸而進行偵測。電位偵測部15係使兩檢查探針13與電路基板1之導體圖案2之兩端部接觸而偵測自直流電流源12流通固定之電流時的檢查探針13間之電位，並對該電位進行A/D(Analog to Digital，類比/數位)轉換而作為數位信號發送至控制部16。切換開關14具有如下兩種功能：將直流電流源12與檢查探針13之間之連接接通(ON)、斷開(OFF)而使對檢查探針13之通電開始或停止；及對將該等直流電流源12與檢查探針13設為連接狀態時之對於兩檢查探針13之電流之流通方向進行切換。然而，於本發明中，亦可分開設置該等兩個功能。控制部16係包括CPU(Central Processing Unit，中央處理單元)、記憶體等，對直流電流源12及切換開關14進行控制，並且根據電位偵測部15之偵測電位對電路基板1是否良好進行判定者，且設置有設定各種條件等之條件設定部23、判定電路基板1是否良好之檢查判定部24、對測定之反覆進行控制之反覆控制部25、對測定時之電流方向進行控制之電流方向控制部26、進行與各部之間之資料通信之通信部27。條件設定部23可設定藉由直流電流源12而產生之定電流值、用以於檢查判定部24中確定測定值是否為容許範圍之臨限值、測定次數之上限等。該等定電流值、臨限值、測定次數之上限等係根據成為檢查對象之電路基板之特性而設定為適當值。 檢查判定部24係擷取自電位偵測部15發送來之資料(電位)，根據與預先對直流電流源12設定之定電流值之關係而計算電阻值，並將該電阻值與臨限值(導通狀態為良好之情形時之最大容許電阻值)進行比較，根據哪一個較小之比較結果而判定電路基板1是否良好。 反覆控制部25係以如下方式進行控制：於未由檢查判定部24判定為良好之情形時，在特定條件下反覆進行特定次數之測定。電流方向控制部26係對藉由反覆控制部25之控制而反覆進行測定之情形時的電流之方向進行控制。關於以上之控制部16之控制之詳細內容，將於以下之基板檢查方法之說明中進行說明。[基板檢查方法]根據圖1之流程圖，對基板檢查方法進行說明。於進行電路基板1之導通檢查之情形時，使檢查探針13與導體圖案2之兩端部接觸，首先設為將流動至導體圖案2之電流之方向設定為任一方向之狀態(S1：電流方向初始設定)。其次，將測定次數i設定為1(S2)，並藉由將切換開關14設為接通而開始對檢查探針13間通電(S3)。若特定之電流流動至檢查探針13間之導體圖案2，則藉由電位偵測部15檢測上述檢查探針13間之電位(S4)，並於偵測電位後，阻斷電流(S5)。繼而，根據該電位與對直流電流源12預先所設定之電流值而運算電阻值(S6)。或者，亦可於該S6中，另外準備電流檢測機構，使用在通電中實測到之電流值而計算電阻值。對檢查探針13間之導體圖案2流通電流而檢測電位，根據該電位計算電阻值，將截至於下一步驟S7中將該電阻值與臨限值R0進行比較為止的程序設為1次測定，將於該期間計算出之電阻值設為測定值Ri(i=1~n)。判斷該測定值Ri(i=1~n)是否為預先所設定之臨限值R0以下(S7)，於判斷為Ri≤R0之情形、即判斷為測定值Ri為容許範圍內之情形時，將該電路基板1判定為「良」(S8)。於在S7中未判斷為測定值Ri為臨限值R0以下(Ri≤R0)之情形時，判斷該測定是否為第n次測定(S9)，於判斷為第n次之情形時，將該電路基板判定為「不良」(S10)。該n次之值預先由條件設定部23設定。測定次數為第n次係指於至此為止之期間測定值Ri均未成為臨限值R0以下，且於即便達到上限之n次但測定值Ri未達到臨限值R0之情形時，將該電路基板1判定為不良。於在S9中判斷為測定次數非為第n次之情形時，判斷該測定是否為第1次測定(S11)，於判斷為第1次之情形時，藉由電流方向控制部26使切換開關14作動而進行電流方向切換之處理(S12)。於在S11中未判斷為第1次測定之情形時，進入至下一步驟S13。於在S11中未判斷為第1次測定之情形時，判斷是否為第2次測定(S13)。於判斷為第2次測定之情形時，將第1次之測定值(電阻值)R1與第2次之測定值(電阻值)R2進行比較而判斷第1次之測定值R1是否小於第2次之測定值R2(S14)。於在S13中未判斷為第2次測定之情形時，進入至下一步驟(S15)。於在S14中判斷為第1次之測定值R1小於第2次之測定值R2之情形時，藉由電流方向控制部26使切換開關14作動而完成電流方向切換處理(S16)。於在S14中未判斷為第1次之測定值R1小於第2次之測定值R2之情形時，不切換電流方向而進入至下一步驟(S15)。即，於第1次之測定值較小之情形(第1次之測定值與臨限值R0之差之值小於第2次之測定值與臨限值R0之差之值的情形)時，選擇進行第1次測定時之電流方向，於第2次之測定值小於第1次之情形(第2次之測定值與臨限值R0之差之值小於第1次之測定值與臨限值R0之差之值的情形)時，選擇進行第2次測定時之電流方向，設為實施第3次之後之檢查之情形時之條件(電流方向)。於S15中，藉由反覆控制部25對測定次數i進行遞增計數，再次自S3反覆進行測定。於該期間，檢查探針13維持與檢查對象之導體圖案2接觸之狀態，僅對切換開關14進行控制。於該一連串處理中，在如下之時檢查結束：因於S7中判斷為測定值Ri為臨限值R0以下而於S8中判定為良好；及即便反覆進行測定，測定值Ri亦未成為臨限值R0以下，故而儘管於S9中測定次數已達到上限之n次，於S10中亦判定為不良。於因判定為良好而檢查結束之情形、例如第1次測定判定為良好之情形時，藉由1次測定而檢查結束，於未等待測定次數i成為n次而判定為良好之時間點，檢查結束。又，對於測定時之電流方向，於自最初開始完成2次測定之時間點，判斷第1次之測定值R1是否小於第2次之測定值R2(S14)，於判斷為第1次之測定值R1小於第2次之測定值R2之情形時，為了採用上述第1次測定時之電流方向而切換電流方向(S16)，於未判斷為第1次之測定值R1較小之情形時，不改變電流方向地、換言之、維持第2次測定時之電流方向而進行之後之測定。即，以2次之測定值中之偏離容許範圍之差之值較小之測定值時的電流方向進行第3次之後之測定。若每當進行測定時均一面交替地切換電流之方向一面進行測定，則測定值逐漸收斂成特定值，但交替地測定出較大之測定值與較小之測定值。因此，於測定值成為臨限值以下之前需要時間，但藉由設為本實施形態之檢查方法而測定值於較早之時間點成為基準值R0以下。圖3A及圖3B係將測定次數n設定為10次，以曲線圖形式表示藉由反覆進行測定而產生之測定值之變化者。圖3A表示第1次之測定值大於第2次之測定值之情形，圖3B表示第2次之測定值大於第1次之測定值之情形。又，於任一圖中，虛線均表示每當進行測定時均一面交替地改變電流之方向一面進行測定之情形。實線表示如下情形，即，與本實施形態相同，於最初之測定及第2次測定時切換電流方向，但第3次之後係以測定出第1次與第2次之測定值中之較小之測定值、即偏離容許範圍之差之值較小之測定值時的電流方向進行測定。於各圖之上段表示一面交替地切換電流方向一面進行檢查之情形時之電流方向之變化，於下段表示藉由本實施形態之檢查方法產生之電流方向之變化。於本實施形態之檢查方法中，於圖3A所示之例中，第2次之測定值小於第1次之測定值，因此，以與第2次測定時相同之電流方向(-方向)進行第3次之後之測定。於圖3B所示之例中，第1次之測定值小於第2次之測定值，因此，以與第1次測定時相同之電流方向(+方向)進行第3次之後之測定。如該等圖3A及圖3B所示，可知如下內容：與每當進行測定時均一面交替地切換電流方向一面進行測定之情形(以虛線表示之情形)相比，於如下情形時，於更早之時間點(於圖3A及圖3B之情形時為第5次測定)低於臨限值R0，即，將最初之2次為止之測定值進行比較，採用測定出偏離測定值之容許範圍之差之值較小的測定值時之電流方向，之後以該電流方向流通電流而進行檢查(以實線表示之情形)。附帶而言，圖4表示完全不改變電流方向而自最初開始於同一方向(於圖4所示之例中為+方向)上流通電流而反覆測定同一導體圖案之情形時的測定值之變化。於該情形時，測定次數越是增加，則測定值越小，但於成為臨限值R0以下之前亦需要時間。藉由如此般於電路基板之導通檢查時反覆進行測定，可減少檢查探針13之接觸狀態等之影響而準確地測定導體圖案2之電阻值，於該情形時，對最初之2次切換電流方向而進行測定，對第3次之後以測定出第1次與第2次之測定值中之與容許範圍(臨限值)之差較小之測定值時的電流方向進行測定，藉此，可於較早之時間點設為臨限值R0以下，從而可謀求檢查時間之縮短。再者，於上述實施形態中，作為本發明之基板檢查方法及基板檢查裝置，應用於使檢查探針與導體圖案之兩端部接觸而對導體圖案之斷線等進行檢查之導通檢查，但亦可於使檢查探針與個別之導體圖案接觸而對導體圖案間之絕緣狀態進行檢查之絕緣檢查時應用本發明。圖5及圖6表示將本發明應用於絕緣檢查之第2實施形態，圖5係用於絕緣檢查之基板檢查方法之流程圖，圖6係基板檢查裝置之系統方塊圖。於該第2實施形態之基板檢查裝置11'中，設置有直流電壓源12'而代替第1實施形態之基板檢查裝置11之直流電流源12，且設置有電位・電流偵測部15'而代替電位偵測部15。而且，係如下構成：藉由電位・電流偵測部15'偵測自直流電壓源12'對分別與兩個導體圖案2接觸之檢查探針13間施加電壓時的檢查探針13間之電位及電流。關於其他構成，除與該等直流電壓源12'、電位・電流偵測部15'對應地變更之部分(於下述之絕緣檢查方法中進行說明)以外，與第1實施形態之基板檢查裝置11相同，對共通部分標註相同之符號而省略說明。於使用該基板檢查裝置11'進行電路基板1之絕緣檢查之情形時，首先預先設定藉由切換開關14而施加至導體圖案2間之電壓(及藉由施加電壓而流通之電流之方向)(S1')。其次，將測定次數i設定為1(S2)，並藉由將切換開關14設為接通而向檢查探針13間施加電壓(電流)(S3')。若向檢查探針13所接觸之兩導體圖案2間施加特定之電壓，則藉由電位・電流偵測部15'而檢測該兩個導體圖案2間之電位及電流(自高電位側流向低電位側之電流)(S4')，於偵測該電位、電流後，停止施加電壓(S5')。繼而，根據該電位及電流而運算電阻值(測定值Ri)(S6)。於該絕緣檢查之情形時，於基板正常之情形時獲得特定之容許範圍內之測定值(電阻值)。若將該容許範圍之下限之臨限值設為Ra並將上限之臨限值設為Rb，則於基板正常之情形時，成為Ra≤Ri≤Rb。因此，預先設定該上限之臨限值Ra與下限之臨限值Rb，判斷測定值Ri是否為該容許範圍(S7')，於判斷為該容許範圍(Ra≤Ri≤Rb)內之情形時，判定為良好(S8)。之後，S9至S15之各步驟係與上述第1實施形態之情形相同，於S15中對測定次數i進行遞增計數，再次重複自S3'起之步驟。於該絕緣檢查中，使檢查探針13分別與兩個導體圖案2接觸，跨及該等導體圖案2而施加電壓，藉此對導體圖案2間之絕緣狀態進行檢查。又，由於自直流電壓源12'施加電壓，故而於S12及S16之電流方向切換之步驟中，藉由切換電壓之施加方向而切換流通之電流之方向。即，於該絕緣檢查時，施加電壓而測定自高電位側流向低電位側之電流，利用藉由改變該電壓之施加方向而流通之電流之方向改變這一情況進行檢查。於該絕緣檢查時，亦於測定值落入上限之臨限值Ra與下限之臨限值Rb之範圍(Ra≤Ri≤Rb)之情形時判定為良好，於未判定為落入該容許範圍之情形時，於第1次測定與第2次測定時改變電壓之方向而進行測定，以測定出任一較小之測定值、即偏離容許範圍之差之值較小之測定值時流通的電流之方向進行以後之測定。若將依存於設置於並排之導體圖案間之材料之電阻率設為ρ，將導體圖案間(空間)之長度設為L，將導體圖案間之導體圖案之側壁面積設為A，則並排之導體圖案間之絕緣電阻值Rx以Rx=ρ・L/A表示。上述上限之臨限值Ra與下限之臨限值Rb亦可考慮L、A、ρ之偏差而決定。或者，亦可累計絕緣檢查之測定值，根據統計解析而決定。圖7A及圖7B係表示絕緣檢查之測定值之推移之曲線圖，且係將利用第2實施形態之絕緣檢查方法檢查電路基板之情形、與每次進行測定時一面交替地切換電流方向一面對電路基板進行絕緣檢查之情形進行比較，而表示測定次數與測定值之關係的曲線圖。於圖7A及圖7B中，第2次之測定值均為小於第1次之測定值之值，但因接觸電阻等影響而表現出高於臨限值(Ra、Rb)之電阻值。而且，於圖7A中，以測定值較小之第2次之電流方向、即測定出偏離容許範圍之差之值小於第1次之第2次之測定值時的電流方向反覆進行測定，藉此根據測定值落在上限之臨限值Rb與下限之臨限值Ra之範圍內、即成為容許範圍內，而判斷為絕緣狀態良好。於一面交替地切換電流方向一面進行測定之情形時，如虛線所示，於到達容許範圍內之前需要一段時間。另一方面，於圖7B中表示對導體圖案間產生短路而絕緣不良之基板進行絕緣檢查之例。於該圖7B之情形時，於在測定初始階段消除接觸電阻等障壁後，立即成為短路電阻值(低於下限之臨限值Ra之電阻值)，而判定為絕緣不良。該絕緣檢查之情形時亦與導通檢查之情形相同，採用測定出第1次之測定值與第2次之測定值中之較小的測定值時、即測定出偏離容許範圍之差之值較小之測定值時的電流方向進行第3次之後之測定，藉此可於較早之階段進行良好與否之判定。上述第1實施形態之導通檢查之情形時之測定值的容許範圍係使用一個臨限值而進行判斷，測定值成為容許範圍內係指測定值成為臨限值以下。另一方面，第2實施形態之絕緣檢查之情形時之容許範圍係上限之臨限值與下限之臨限值之間之範圍，測定值成為容許範圍內係指測定值成為上限之臨限值與下限之臨限值之間之範圍內。再者，於導通檢查之情形時，亦可預先設定上限之臨限值與下限之臨限值，於測定值處於上限之臨限值與下限之臨限值之間之情形時，判斷為良品。再者，於任一實施形態中，均根據檢查探針13間之電位及電流計算電阻值，並根據該電阻值而判定電路基板是否良好，但於例如第1實施形態中，亦可基於在檢查探針13間偵測到之電位本身之值而判定是否良好，於本發明中，包括該等電位及電阻值等而設為電特性值。Hereinafter, embodiments of the present invention will be described with reference to the drawings. [Substrate inspection device] The substrate inspection device 11 according to the first embodiment is configured to conduct conduction inspection of the conductor pattern 2 of the circuit board 1. As shown in FIG. 2, the substrate inspection device 11 includes a DC current source 12 that generates a specific DC current. The probe 13 is in contact with both end portions of the conductor pattern 2 exposed on the circuit board 1; a switch (switching mechanism) 14 is disposed between the inspection probe 13 and the DC current source 12; a portion 15 for detecting the potential between the inspection probes 13; a control portion 16 for controlling energization of the inspection probe 13 and determining whether the circuit substrate 1 is good; and a display portion 17 for displaying the determination result, etc. . As the inspection probe 13, for example, a two-terminal is used, and each probe is contacted with the conductor pattern 2 for detection. The potential detecting unit 15 is configured to bring the two inspection probes 13 into contact with both end portions of the conductor pattern 2 of the circuit board 1 to detect the potential between the inspection probes 13 when the DC current source 12 flows and fixes the current, and The potential is converted to A/D (Analog to Digital) and transmitted to the control unit 16 as a digital signal. The changeover switch 14 has two functions: turning ON/OFF the connection between the DC current source 12 and the inspection probe 13 to start or stop the energization of the inspection probe 13; When the DC current source 12 and the inspection probe 13 are in a connected state, the flow directions of the currents of the two inspection probes 13 are switched. However, in the present invention, these two functions can also be set separately. The control unit 16 includes a CPU (Central Processing Unit), a memory, and the like, and controls the DC current source 12 and the changeover switch 14, and determines whether the circuit board 1 is good or not based on the detection potential of the potential detecting unit 15. The judger is provided with a condition setting unit 23 that sets various conditions and the like, an inspection determination unit 24 that determines whether the circuit board 1 is good, a reverse control unit 25 that controls the measurement repeatedly, and a current that controls the current direction during measurement. The direction control unit 26 performs a communication unit 27 for data communication with each unit. The condition setting unit 23 can set a constant current value generated by the DC current source 12, a threshold value for determining whether the measured value is the allowable range, an upper limit of the number of measurements, and the like. The constant current value, the threshold value, the upper limit of the number of measurement times, and the like are set to appropriate values in accordance with the characteristics of the circuit board to be inspected. The inspection determining unit 24 extracts the data (potential) transmitted from the potential detecting unit 15, calculates the resistance value based on the relationship with the constant current value set in advance to the DC current source 12, and calculates the resistance value and the threshold value. (The maximum allowable resistance value in the case where the conduction state is good) is compared, and it is determined whether or not the circuit board 1 is good based on which of the smaller comparison results. The reverse control unit 25 performs control such that when it is determined that the inspection determination unit 24 is not good, the measurement is repeated a specific number of times under specific conditions. The current direction control unit 26 controls the direction of the current when the measurement is repeatedly performed by the control of the reverse control unit 25. The details of the control of the above control unit 16 will be described in the following description of the substrate inspection method. [Substrate Inspection Method] A substrate inspection method will be described based on the flowchart of Fig. 1 . When the conduction inspection of the circuit board 1 is performed, the inspection probe 13 is brought into contact with both end portions of the conductor pattern 2, and first, the direction of the current flowing to the conductor pattern 2 is set to any one of the directions (S1: Current direction initial setting). Next, the number of measurements i is set to 1 (S2), and energization between the inspection probes 13 is started by turning on the changeover switch 14 (S3). When a specific current flows to the conductor pattern 2 between the inspection probes 13, the potential detecting portion 15 detects the potential between the inspection probes 13 (S4), and after detecting the potential, blocks the current (S5). . Then, the resistance value is calculated based on the potential and the current value set in advance to the DC current source 12 (S6). Alternatively, in S6, a current detecting means may be separately prepared, and the resistance value may be calculated using the current value actually measured during energization. A current is detected in the conductor pattern 2 between the inspection probes 13 to detect a potential, and the resistance value is calculated based on the potential, and the program until the resistance value is compared with the threshold value R0 in the next step S7 is determined as one measurement. The resistance value calculated during this period is set to the measured value Ri (i = 1 to n). It is determined whether or not the measured value Ri (i=1 to n) is equal to or less than the preset threshold value R0 (S7). When it is determined that Ri ≤ R0, that is, when the measured value Ri is determined to be within the allowable range, The circuit board 1 is judged to be "good" (S8). When it is not determined in S7 that the measured value Ri is equal to or less than the threshold value R0 (Ri ≤ R0), it is determined whether or not the measurement is the nth measurement (S9), and when it is determined that the nth time is the case, the The circuit board is judged to be "defective" (S10). The value of the nth time is set in advance by the condition setting unit 23. When the number of times of measurement is the nth time, the measured value Ri does not become the threshold value R0 or less, and the circuit does not reach the threshold value R0 even if the upper limit is reached n times. The substrate 1 was judged to be defective. When it is determined in S9 that the number of times of measurement is not the nth time, it is determined whether or not the measurement is the first measurement (S11), and when it is determined that the first time is the case, the current direction control unit 26 causes the changeover switch. The process of switching the current direction is performed by the operation of 14 (S12). If it is not determined in the first measurement in S11, the process proceeds to the next step S13. When it is not determined in the case of the first measurement in S11, it is determined whether or not the second measurement is performed (S13). When it is determined that the second measurement is performed, the first measurement value (resistance value) R1 is compared with the second measurement value (resistance value) R2 to determine whether the first measurement value R1 is smaller than the second time. The second measured value is R2 (S14). If it is not determined in the case of the second measurement in S13, the process proceeds to the next step (S15). When it is determined in S14 that the first measurement value R1 is smaller than the second measurement value R2, the current direction control unit 26 activates the changeover switch 14 to complete the current direction switching process (S16). When it is not determined in S14 that the first measurement value R1 is smaller than the second measurement value R2, the current direction is not switched and the process proceeds to the next step (S15). In other words, when the measured value of the first time is small (when the value of the difference between the measured value of the first time and the threshold value R0 is smaller than the value of the difference between the second measured value and the threshold value R0), The current direction when the first measurement is performed is selected, and the second measurement value is smaller than the first time (the difference between the second measurement value and the threshold value R0 is smaller than the first measurement value and threshold) In the case of the value of the difference of the value of R0, the direction of the current in the second measurement is selected, and the condition (current direction) in the case of performing the inspection after the third time is selected. In S15, the overtaking control unit 25 counts up the number of measurements i, and repeats the measurement from S3. During this period, the inspection probe 13 maintains the state in contact with the conductor pattern 2 to be inspected, and only the changeover switch 14 is controlled. In the series of processes, the inspection is completed as follows: since it is determined in S7 that the measured value Ri is equal to or less than the threshold value R0, it is judged to be good in S8; and even if the measurement is repeated, the measured value Ri does not become a threshold. Since the value is equal to or less than R0, although the number of times of measurement in S9 has reached the upper limit n times, it is judged to be defective in S10. When the inspection is completed and the inspection is completed, for example, when the first measurement is judged to be good, the inspection is completed by one measurement, and the time is judged to be good when the number of measurement times i is not n times. End. In the current direction at the time of measurement, it is determined whether or not the first measurement value R1 is smaller than the second measurement value R2 (S14) at the time point when the measurement is completed twice from the beginning, and it is determined that the measurement is the first time. When the value R1 is smaller than the second measurement value R2, the current direction is switched in order to use the current direction in the first measurement (S16), and when it is not determined that the first measurement value R1 is small, The subsequent measurement is performed without changing the direction of the current, in other words, maintaining the current direction at the time of the second measurement. In other words, the measurement is performed after the third time in the current direction at the time when the value of the difference between the allowable ranges and the difference between the allowable ranges is smaller. When the measurement is performed while alternately switching the direction of the current every time the measurement is performed, the measured value gradually converges to a specific value, but the larger measured value and the smaller measured value are alternately measured. Therefore, it takes time until the measured value becomes equal to or less than the threshold value. However, the measurement value is set to the reference value R0 or less at an earlier time point by the inspection method of the present embodiment. 3A and 3B show the number of times of measurement n is set to 10 times, and the change of the measured value which is produced by repeated measurement is shown in a graph form. 3A shows a case where the measured value of the first time is larger than the measured value of the second time, and FIG. 3B shows a case where the measured value of the second time is larger than the measured value of the first time. Further, in any of the drawings, the broken line indicates the case where the measurement is performed while changing the direction of the current alternately every time the measurement is performed. The solid line indicates a case where the current direction is switched between the first measurement and the second measurement as in the present embodiment, but after the third time, the first and second measurement values are measured. The measured value of the small measured value, that is, the measured value which is smaller than the difference between the allowable ranges, is measured. The upper part of each figure shows the change of the current direction when the current direction is alternately switched, and the change of the current direction by the inspection method of this embodiment is shown in the lower part. In the inspection method of the present embodiment, in the example shown in FIG. 3A, since the measured value of the second time is smaller than the measured value of the first time, the same current direction (-direction) as in the second measurement is performed. The measurement after the third time. In the example shown in FIG. 3B, since the measured value of the first time is smaller than the measured value of the second time, the measurement is performed after the third time in the same current direction (+ direction) as in the first measurement. As shown in FIG. 3A and FIG. 3B, it is understood that the measurement is performed while the current direction is alternately changed every time the measurement is performed (in the case of a broken line), as compared with the case where The early time point (the fifth measurement in the case of FIGS. 3A and 3B) is lower than the threshold value R0, that is, the measured values from the first two times are compared, and the allowable range from the measured value is measured. The direction of the current at the time when the value of the difference is small is measured, and then the current is passed in the direction of the current to be inspected (indicated by a solid line). Incidentally, FIG. 4 shows a change in the measured value when the current is flown in the same direction (the + direction in the example shown in FIG. 4) and the same conductor pattern is repeatedly measured from the beginning without changing the current direction. In this case, the more the number of measurements is increased, the smaller the measured value is, but it takes time before the threshold value R0 or lower. By repeating the measurement during the conduction inspection of the circuit board as described above, the influence of the contact state of the inspection probe 13 and the like can be reduced, and the resistance value of the conductor pattern 2 can be accurately measured. In this case, the first two switching currents are used. The measurement is performed in the direction, and the current direction when the measurement value which is smaller than the allowable range (threshold value) among the measured values of the first time and the second time is measured after the third time is measured. It can be set to the threshold value R0 or less at an earlier time point, and the inspection time can be shortened. Furthermore, in the above-described embodiment, the substrate inspection method and the substrate inspection device of the present invention are applied to a conduction inspection in which the inspection probe is brought into contact with both end portions of the conductor pattern to inspect the disconnection of the conductor pattern or the like. The present invention can also be applied to an insulation inspection in which an inspection probe is brought into contact with an individual conductor pattern to inspect an insulation state between conductor patterns. 5 and 6 show a second embodiment in which the present invention is applied to insulation inspection. Fig. 5 is a flowchart of a substrate inspection method for insulation inspection, and Fig. 6 is a system block diagram of a substrate inspection apparatus. In the substrate inspection apparatus 11' of the second embodiment, a DC voltage source 12' is provided instead of the DC current source 12 of the substrate inspection apparatus 11 of the first embodiment, and a potential/current detecting unit 15' is provided. Instead of the potential detecting unit 15. Further, the potential/current detecting unit 15' detects the potential between the inspection probes 13 when a voltage is applied between the inspection probes 13 that are in contact with the two conductor patterns 2 from the DC voltage source 12'. And current. Other than the DC voltage source 12' and the potential/current detecting unit 15' (described in the following insulation inspection method), the substrate inspection apparatus according to the first embodiment is used. 11 is the same, and the same reference numerals are given to the same portions, and the description is omitted. When the substrate inspection device 11' is used for the insulation inspection of the circuit board 1, first, the voltage applied between the conductor patterns 2 by the changeover switch 14 (and the direction of the current flowing by applying a voltage) is set in advance ( S1'). Next, the number of measurements i is set to 1 (S2), and a voltage (current) is applied between the inspection probes 13 by turning on the changeover switch 14 (S3'). When a specific voltage is applied between the two conductor patterns 2 that are in contact with the inspection probe 13, the potential and current between the two conductor patterns 2 are detected by the potential/current detecting unit 15' (flow from the high potential side to the low side) The current on the potential side (S4'), after detecting the potential and the current, stops applying the voltage (S5'). Then, the resistance value (measured value Ri) is calculated based on the potential and the current (S6). In the case of the insulation inspection, the measured value (resistance value) within a specific allowable range is obtained when the substrate is normal. When the threshold value of the lower limit of the allowable range is Ra and the threshold value of the upper limit is Rb, Ra≤Ri≤Rb is obtained when the substrate is normal. Therefore, the threshold value Ra of the upper limit value Ra and the lower limit is set in advance, and it is determined whether or not the measured value Ri is the allowable range (S7'), and when it is determined that the allowable range (Ra ≤ Ri ≤ Rb) It is judged to be good (S8). Thereafter, the steps S9 to S15 are the same as those in the first embodiment described above, and the number of measurements i is counted up in S15, and the step from S3' is repeated again. In the insulation inspection, the inspection probes 13 are brought into contact with the two conductor patterns 2, and a voltage is applied across the conductor patterns 2, thereby checking the insulation state between the conductor patterns 2. Further, since a voltage is applied from the DC voltage source 12', in the step of switching the current directions of S12 and S16, the direction of the current flowing is switched by switching the direction in which the voltage is applied. In other words, at the time of the insulation inspection, a current is applied to measure the current flowing from the high potential side to the low potential side, and the direction of the current flowing by changing the direction in which the voltage is applied is changed. In the case of the insulation inspection, the measurement value is judged to be good when the measured value falls within the range of the upper limit value Ra of the upper limit and the lower limit value Rb (Ra ≤ Ri ≤ Rb), and is not determined to fall within the allowable range. In the case of the first measurement and the second measurement, the measurement is performed by changing the direction of the voltage, and the current is measured when any of the smaller measurement values, that is, the measurement value having a smaller value of the difference from the allowable range is measured. The direction is measured in the future. When the resistivity of the material interposed between the conductor patterns arranged in parallel is ρ, the length between the conductor patterns (space) is L, and the side wall area of the conductor pattern between the conductor patterns is A, and the side by side The insulation resistance value Rx between the conductor patterns is expressed by Rx = ρ · L / A. The threshold value Ra of the upper limit value Ra and the lower limit may be determined in consideration of the deviation of L, A, and ρ. Alternatively, the measured value of the insulation inspection may be accumulated and determined based on statistical analysis. 7A and 7B are graphs showing the transition of the measured value of the insulation inspection, and the case where the circuit board is inspected by the insulation inspection method according to the second embodiment, and the current direction is alternately switched every time the measurement is performed. A comparison is made between the case where the circuit board is inspected for insulation, and the relationship between the number of times of measurement and the measured value is shown. In FIGS. 7A and 7B, the second measurement value is a value smaller than the first measurement value, but exhibits a resistance value higher than the threshold value (Ra, Rb) due to the influence of contact resistance or the like. Further, in FIG. 7A, the current direction in the second current direction in which the measured value is small, that is, the value in which the difference between the deviation tolerance ranges is smaller than the measurement value in the second time of the first time is measured, and the measurement is repeated. According to the measured value, it falls within the range of the threshold value Rb of the upper limit and the threshold value Ra of the lower limit, that is, within the allowable range, and it is determined that the insulation state is good. When the measurement is performed while alternately switching the current direction, as indicated by a broken line, it takes a while before reaching the allowable range. On the other hand, an example in which insulation inspection is performed on a substrate which is short-circuited between conductor patterns and has poor insulation is shown in FIG. 7B. In the case of FIG. 7B, immediately after the barrier layer such as the contact resistance is removed in the initial stage of measurement, the short-circuit resistance value (resistance value lower than the lower limit value Ra) is determined, and it is determined that the insulation is poor. In the case of the insulation inspection, the value of the difference between the first measurement value and the second measurement value is measured, that is, the difference between the deviation and the allowable range is measured. The current direction at the time of the small measurement value is measured after the third time, whereby the determination of the goodness or not can be performed at an earlier stage. In the case of the conduction check in the first embodiment, the allowable range of the measured value is determined using one threshold value, and when the measured value is within the allowable range, the measured value is equal to or less than the threshold value. On the other hand, in the case of the insulation inspection in the second embodiment, the allowable range is the range between the upper limit of the upper limit and the threshold of the lower limit, and the measured value is within the allowable range, which means that the measured value becomes the upper limit. Within the range between the threshold and the lower limit. In addition, in the case of the continuity check, the threshold value of the upper limit and the lower limit of the upper limit may be set in advance, and when the measured value is between the threshold of the upper limit and the threshold of the lower limit, it is judged as a good product. . Furthermore, in any of the embodiments, the resistance value is calculated based on the potential and current between the inspection probes 13, and the circuit board is determined to be good based on the resistance value. However, for example, in the first embodiment, The value of the potential detected between the probes 13 is checked to determine whether it is good. In the present invention, the electric potential value is set to include the potential and the resistance value.