Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2003-114568, filed Apr. 18, 2003, the entire contents of which are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a semiconductor device having a TEG (Test Element Group), a semiconductor device manufacturing method, and a semiconductor device test method. 
   2. Description of the Related Art 
   A TEG (Test Element Group) chip obtained by forming the building components (interconnection, transistor, capacitor, resistor, and the like) of a semiconductor device on a chip has conventionally been used to facilitate the reliability evaluation of the semiconductor device or the like. 
   In a conventional TEG chip  10 , as shown in  FIGS. 13 and 14 , a test site (test area) portion  20  and probe pad portion  30  are formed on one silicon substrate  70 . 
   The test site portion  20  is a region where a test element  22  such as a transistor or capacitor exists. The probe pad portion  30  is a region where a probe pad for arranging a probe exists. 
   In the conventional TEG chip  10 , one TEG  11  is constituted by, e.g., the test site portion  20  of three test elements  22  and  16  probe pads  37 . More specifically, the three test elements  22  are arranged at the center of the TEG  11 , and eight probe pads  37  are arranged on each of two sides along the test elements  22 . Each probe pad  37  is electrically connected to the test element  22  via interconnections and contacts in insulating films  71 ,  72 ,  73 ,  74 ,  75 , and  76 . 
   In this situation, the integration degree of semiconductor integrated circuits is increasing year by year. Semiconductor devices to be evaluated at the test site have been downsized. However, probe pads for electrically evaluating a test site are still large despite such reduction in the feature size of semiconductor devices. 
   For example, in the 0.11-μm generation, the probe pad size is 80 μm□ to 100 μm□, and the test site is laid out in almost the same area as the area occupied by the probe pad. Hence, the measurement probe pad occupies 60% of the TEG chip at maximum in the TEG layout. Note that the probe pad means one arranged for only a probe. 
   In the prior art, it is difficult to reduce the probe pad area because the probe pad cannot be shared between a plurality of test elements and the test site is evaluated by a common probe card. 
   As described above, in the prior art, the area occupied by the probe pad in the TEG chip is large, and it is difficult to reduce the probe pad area. The region where the test site can be formed is small, and the test site region is limited by the probe pad area. 
   BRIEF SUMMARY OF THE INVENTION 
   According to the first aspect of the present invention, there is provided a semiconductor device comprising a first layer, a plurality of first test elements which are arranged in the first layer, a second layer which is adhered to the first layer and is different from the first layer, and a plurality of pads which are arranged in the second layer and electrically connected to the first test elements. 
   According to the second aspect of the present invention, there is provided a semiconductor device manufacturing method comprising forming a first layer and a second layer being different from the first layer, the first layer having a plurality of first test elements, the second layer having a plurality of pads, and adhering the first and second layers to electrically connect the first test elements to the pads. 
   According to the third aspect of the present invention, there is provided a semiconductor device test method comprising forming a first layer and a second layer being different from the first layer, the first layer having a plurality of first test elements, the second layer having a plurality of pads, adhering the first and second layers to electrically connect at least some of the test elements to the pads, and evaluating performance of the at least some of the test elements. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
       FIG. 1A  is a plan view showing a TEG chip according to the first embodiment of the present invention; 
       FIG. 1B  is a sectional view showing the TEG chip taken along the line IB—IB in  FIG. 1A ; 
       FIG. 2A  is a plan view showing a test site portion according to the first embodiment of the present invention; 
       FIG. 2B  is a sectional view showing the test site portion taken along the line IIB—IIB in  FIG. 2A ; 
       FIG. 3A  is a plan view showing a probe pad portion according to the first embodiment of the present invention; 
       FIG. 3B  is a sectional view showing the probe pad portion taken along the line IIIB—IIIB in  FIG. 3A ; 
       FIG. 4  is a plan view showing the TEG chip according to the first embodiment of the present invention; 
       FIG. 5A  is a plan view showing a conventional TEG chip; 
       FIG. 5B  is a plan view showing the TEG chip according to the first embodiment of the present invention; 
       FIG. 6A  is a plan view showing a TEG chip according to the second embodiment of the present invention; 
       FIG. 6B  is a sectional view showing the TEG chip taken along the line VIB—VIB in  FIG. 6A ; 
       FIG. 7  is a sectional view showing a test site portion according to the second embodiment of the present invention; 
       FIG. 8  is a sectional view showing an interconnection portion according to the second embodiment of the present invention; 
       FIG. 9  is a sectional view showing a chip carrier portion according to the second embodiment of the present invention; 
       FIG. 10A  is a sectional view showing a state in which the test site portion and interconnection portion according to the second embodiment of the present invention are adhered to each other; 
       FIG. 10B  is a sectional view showing a state in which the test site portion, interconnection portion, and chip carrier portion according to the second embodiment of the present invention are adhered to each other; 
       FIG. 11  is a plan view showing another TEG chip according to the first and second embodiments of the present invention; 
       FIG. 12  is a plan view showing still another TEG chip according to the first and second embodiments of the present invention; 
       FIG. 13  is a plan view showing a conventional TEG chip; and 
       FIG. 14  is a sectional view showing the TEG chip taken along the line XIV—XIV in  FIG. 13 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Preferred embodiments of the present invention will be described below with reference to the several views of the accompanying drawing. In the following description, the same reference numerals denote the same parts throughout all the views. 
   [First Embodiment] 
   In the first embodiment, a TEG (Test Element Group) chip is constituted by a test site portion and probe pad portion. The TEG chip is formed by adhering the test site portion and probe pad portion. 
   A TEG chip according to the first embodiment of the present invention will be described with reference to  FIGS. 1A and 1B . 
   As shown in  FIGS. 1A and 1B , a TEG chip  10  according to the first embodiment is constituted by separately forming a test site (test area) portion  20  and probe pad portion  30  and adhering them into one structure. The test site portion  20  is a region where test elements  22  exist. The probe pad portion  30  is a region where probe pads  37  for arranging a probe exist. 
   One TEG  11  of the TEG chip  10  is constituted by, e.g., the test site portion  20  of three test elements  22  and  16  probe pads  37 . More specifically, the three test elements  22  are arranged at the center of the TEG  11 , and eight probe pads  37  are arranged on each of two sides along the test elements  22 . Each probe pad  37  is electrically connected to a test element  22   a  via interconnections  24  and  35  and contacts  23 ,  34 , and  36  in insulating films  25 ,  31 , and  32 . 
   The test elements  22  at the test site portion  20  are classified into elements  22   a  which are electrically connected to the probe pads  37 , and elements  22   b  which are not electrically connected to the probe pads  37 . In the first embodiment, unlike the prior art, the test elements  22   b  which are not electrically connected to the probe pads  37  exist on a silicon substrate  21  below the probe pads  37 . A portion where each test element  22  overlaps a corresponding probe pad  37  exists in the plan view of the TEG chip  10 . 
   The test site portion according to the first embodiment of the present invention will be described with reference to  FIGS. 2A and 2B . 
   As shown in  FIGS. 2A and 2B , the test elements  22  are formed on the entire surface of the silicon substrate  21  at the test site portion  20  according to the first embodiment. Each contact  23  which is connected to a corresponding test element  22  is formed in the insulating film  25 . The interconnection (pad)  24  which is connected to the contact  23  is formed. The upper surface of the interconnection  24  is exposed outside the insulating film  25 , and serves as a connection portion for electrically connecting the probe pad portion  30 . 
   A plurality of test elements  22  at the test site portion  20  are arranged on the whole TEG chip  10  at a predetermined interval (test site pitch P 1 ). The test site pitch P 1  is set using, as a reference, a pad set which is a standard in each device generation. 
   Examples of the test element  22  are a memory element such as an SRAM, DRAM, FeRAM, or MRAM, a capacitor, a resistor, and an interconnection. 
   The surface shape of the test element  22  may be a rectangular, as shown in  FIG. 2A , or can be changed to various shapes such as a square and circle. 
   The probe pad portion according to the first embodiment of the present invention will be described with reference to  FIGS. 3A and 3B . 
   As shown in  FIGS. 3A and 3B , the probe pad portion  30  according to the first embodiment is comprised of the probe pads  37  and multilayer interconnections. More specifically, each contact  34 , interconnection  36 , and probe pad  37  are formed in the insulating films  31  and  32 . An insulating film (passivation film)  33  having openings  38  is so formed as to expose part of the upper surface of each probe pad  37 . The lower surface of the contact  34  is exposed outside the insulating film  31 , and serves as a connection portion for electrically connecting the test site portion  20 . 
   A plurality of probe pads  37  at the probe pad portion  30  are arranged on the entire TEG chip  10  at a predetermined interval (pad pitch P 2 ) in the row direction (lateral direction on the sheet surface) and a predetermined interval (pad P 3 ) in the column direction (longitudinal direction on the sheet surface). The pad pitch P 2  in the row direction is set using, as a reference, a pad set which is a standard in each device generation. The pad pitch P 3  in the column direction is set using the minimum pitch of the probe pin as a reference. 
   A TEG chip manufacturing method according to the first embodiment of the present invention will be explained. 
   A test site portion  20  and probe pad portion  30  are separately formed. 
   The test site portion  20  is formed, e.g., as follows. A test element  22  such as an SRAM or DRAM is formed on a silicon substrate  21 , and the test element  22  is buried in an insulating film  25 . An opening is formed in the insulating film  25 , and filled with a metal film to form a contact  23 . An interconnection  24  is formed from a metal film on the contact  23 . 
   The probe pad portion  30  is formed, e.g., as follows. An opening is formed in an insulating film  31 , and filled with a metal film to form a contact  34 . An interconnection  35  is formed and connected to the contact  34 . An insulating film  32  is so formed as to bury the interconnection  35 . An opening is formed in the insulating film  32 , and filled with a metal film to form a contact  36 . A probe pad  37  is formed and connected to the contact  36 . An insulating film  33  is formed on the probe pad  37 , and then an opening  38  is formed in the insulating film  33 . Part of the upper surface of the probe pad  37  is exposed outside. 
   After the test site portion  20  and probe pad portion  30  are separately formed, they are adhered to each other. 
   More specifically, the upper surface of the silicon substrate  21  at the test site portion  20  and the lower surface of the probe pad  37  at the probe pad portion  30  are positioned to face each other. The test site portion  20  and probe pad portion  30  are so adhered as to bring the interconnection  24  of the test site portion  20  and the contact  34  of the probe pad portion  30  into contact with each other. As a result, part of the test element  22  is electrically connected to the probe pad  37  to complete the TEG chip  10 . 
   A TEG chip test method according to the first embodiment of the present invention will be explained. 
   The test site portion  20  and probe pad portion  30  are separately formed. 
   The test site portion  20  and probe pad portion  30  are adhered to each other, and part of the test element  22  and the probe pad  37  are electrically connected to each other. 
   A probe is brought into contact with the probe pad  37  of the probe pad portion  30  to evaluate the performance of the test element  22 . 
   Although a plurality of test elements  22  are formed at the test site portion  20 , test elements  22  to be evaluated in this test method are only ones which are electrically connected to the probe pads  37 . In  FIG. 1B , the test elements  22   a  which are electrically connected to the probe pads  37  can be tested and evaluated. The test elements  22   b  which are not electrically connected to the probe pads  37  cannot be tested and evaluated. 
   In the first embodiment, of a plurality of test elements  22  formed on the TEG chip  10 , only test elements  22  to be tested and evaluated can be selected, tested, and evaluated. For example, objects to be evaluated can be selected, tested, and evaluated by the following method. 
   As shown in  FIG. 4 , a plurality of test elements  22  are classified by the element type. Test elements  22  of the same type are so aligned as to arrange test elements of different types in respective columns. 
   For example, test elements  22  formed from SRAMs are arranged in first groups  12   a ,  12   b ,  12   c , and  12   d . Test elements  22  formed from DRAMS are arranged in second groups  13   a ,  13   b ,  13   c , and  13   d . Test elements  22  formed from MRAMs are arranged in third groups  14   a ,  14   b ,  14   c , and  14   d.    
   In this example, when the test site portion  20  and probe pad portion  30  are adhered, as shown in  FIG. 4 , only the test elements  22  formed from SRAMs in the first groups  12   a ,  12   b ,  12   c , and  12   d  can be evaluated. 
   When the probe pad portion  30  in  FIG. 4  is shifted right on the sheet surface, and the test elements  22  in the second groups  13   a ,  13   b ,  13   c , and  13   d  are electrically connected to the probe pads  37 , only the test elements  22  formed from DRAMs in the second groups  13   a ,  13   b ,  13   c , and  13   d  can be evaluated. Similarly, when the probe pad portion  30  in  FIG. 4  is shifted left on the sheet surface, and the test elements  22  in the third groups  14   a ,  14   b ,  14   c , and  14   d  are electrically connected to the probe pads  37 , only the test elements  22  formed from MRAMs in the third groups  14   a ,  14   b ,  14   c , and  14   d  can be evaluated. 
   According to the first embodiment, the test site portion  20  and probe pad portion  30  are separately formed and adhered. The test element  22  can be formed on the silicon substrate  21  regardless of the area occupied by the probe pad  37 . The region of the test element  22  is, therefore, free from any limitations by the area of the probe pad  37 . This yields the following effects. 
   The test elements  22  are arranged at the pitch P 1 ′ in the prior art, but can be arranged at a pitch P 1  of P 1 ′/N in the first embodiment. The first embodiment, therefore, allows arranging N times of the number of conventional test elements  22  at maximum on the entire surface of the silicon substrate  21 . 
   For example, when the test elements  22  are arranged at the pitch P 1 ′ in the prior art (see  FIG. 5A ), the test elements  22  can be arranged in the first embodiment at the pitch P 1  which is ⅓ the pitch P 1 ′ (see  FIG. 5B ). In this case, three times of the number of conventional test elements  22  can be arranged on the entire surface of the silicon substrate  21 . 
   Since the number of test elements  22  can be increased, the number of types of test elements  22  to be evaluated can be increased. This is very effective because many test elements of different types can be arranged on a system LSI on which various devices are formed on a single substrate. 
   According to the first embodiment, the test elements  22  are classified by the type, and test elements  22  of the same type are aligned. The adhering portions of the test site portion  20  and probe pad portion  30  can be adjusted to select elements to be evaluated out of a plurality of test elements  22 . 
   [Second Embodiment] 
   The second embodiment adopts an area bump. A TEG chip is constituted by a test site portion, interconnection portion, and chip carrier portion. The TEG chip is formed by adhering the test site portion, interconnection portion, and chip carrier portion. 
   In the second embodiment, the same reference numerals as in the first embodiment denote the same parts, and a description thereof will be omitted or simplified. Different parts will be mainly described. 
   A TEG chip according to the second embodiment of the present invention will be described with reference to  FIGS. 6A and 6B . A solder ball is not illustrated in  FIG. 6A . 
   As shown in  FIGS. 6A and 6B , a TEG chip  10  according to the second embodiment is constituted by separately forming a test site portion  20 , interconnection portion  40 , and chip carrier portion  50  and adhering them into one structure. 
   A plurality of test elements  22  at the test site portion  20  are arranged at a high density on a silicon substrate  21 . The test elements  22  are classified into elements  22   a  which are electrically connected to solder balls  61  via interconnections  24 ,  45 ,  49 ,  56 ,  58 , and  60 , contacts  23 ,  44 ,  46 ,  57 , and  59 , and bumps  47 , and elements  22   b  which are not electrically connected to the solder balls  61 . In the second embodiment, the test elements  22   b  which are not electrically connected to the solder balls  61  exist on the silicon substrate  21  below the bumps  47 . A portion where each test element  22  overlaps a corresponding bump  47  exists in the plan view of the TEG chip  10 . 
     FIG. 7  shows the test site portion according to the second embodiment of the present invention. The structure is the same as that in the first embodiment, and a description thereof will be omitted. 
   The interconnection portion according to the second embodiment of the present invention will be explained with reference to  FIG. 8 . 
   As shown in  FIG. 8 , the interconnection portion  40  according to the second embodiment is comprised of the bumps  47  and multilayer interconnections. More specifically, the contacts  44  and  46  and the interconnections  45  and  49  are formed in insulating films  41  and  42 . An insulating film  43  having openings  48  is so formed as to expose part of the upper surface of each interconnection (pad)  49 . The bump  47  is formed on the exposed surface of the interconnection  49 . The lower surface of the contact  44  is exposed outside the insulating film  41 , and serves as a connection portion for electrically connecting the test site portion  20 . The bump  47  serves as a connection portion for electrically connecting the chip carrier portion  50 . 
   Pluralities of bumps  47  and interconnections  49  at the interconnection portion  40  are arranged on the entire TEG chip  10  at, e.g., a predetermined interval (pad pitch P 2 ) in the row direction and a predetermined interval (pad pitch P 3 ) in the column direction, similar to the first embodiment. 
   The chip carrier portion according to the second embodiment of the present invention will be explained with reference to  FIG. 9 . 
   As shown in  FIG. 9 , the chip carrier portion  50  according to the second embodiment is constituted by the solder balls  61  and multilayer interconnections. More specifically, the contacts  57  and  59  and the interconnections  56 ,  58 , and  60  are formed in insulating films  51 ,  52 ,  53 ,  54 , and  55 . The solder balls  61  are formed on the interconnection  60 . The lower surface of the interconnection  56  is exposed outside the insulating film  51 , and serves as a connection portion for electrically connecting the interconnection portion  40 . 
   A TEG chip manufacturing method according to the second embodiment of the present invention will be explained. 
   A test site portion  20 , interconnection portion  40 , and chip carrier portion  50  are separately formed. 
   The test site portion  20  is formed by, e.g., the same method as that in the first embodiment. 
   The interconnection portion  40  is formed, e.g., as follows. An opening is formed in an insulating film  41 , and filled with a metal film to form a contact  44 . An interconnection  45  is formed and connected to the contact  44 . An insulating film  42  is so formed as to bury the interconnection  45 . An opening is formed in the insulating film  42 , and filled with a metal film to form a contact  46  and interconnection  49 . An insulating film  43  is formed on the interconnection  49 , and then an opening  48  is formed in the insulating film  43 . A bump  47  is formed in the opening  48 . 
   The chip carrier portion  50  is formed, e.g., as follows. An interconnection  56  is formed in the insulating film  51 , and an insulating film  52  is formed on the interconnection  56 . An opening is formed in the insulating film  52 , and filled with a metal film to form a contact  57 . An interconnection  58  is formed and connected to the contact  57 . An insulating film  53  is so formed as to bury the interconnection  58 . An insulating film  54  is formed on the insulating film  53 . An opening is formed in the insulating film  54 , and filled with a metal film to form a contact  59 . An interconnection  60  is formed and connected to the contact  59 . An insulating film  55  is so formed as to bury the interconnection  60 . A solder ball  61  is formed on the interconnection  60 . 
   After the test site portion  20 , interconnection portion  40 , and chip carrier portion  50  are separately formed, the test site portion  20  and interconnection portion  40  are adhered to each other, as shown in  FIG. 10A . 
   More specifically, the upper surface of the silicon substrate  21  at the test site portion  20  and the lower surface of the bump  47  at the interconnection portion  40  are positioned to face each other. The test site portion  20  and interconnection portion  40  are so adhered as to bring the pad  24  of the test site portion  20  and the contact  44  of the interconnection portion  40  into contact with each other. As a result, part of the test element  22  is electrically connected to the bump  47 . 
   Thereafter, the test site portion  20 , interconnection portion  40 , and chip carrier portion  50  are adhered to each other, as shown in  FIG. 10B . 
   More specifically, the upper surface of the bump  47  at the interconnection portion  40  and the lower surface of the solder ball  61  at the chip carrier portion  50  are positioned to face each other. The interconnection portion  40  and chip carrier portion  50  are so adhered as to bring the bump  47  of the interconnection portion  40  and the interconnection  56  of the chip carrier portion  50  into contact with each other, thereby completing the TEG chip  10 . 
   A TEG chip test method according to the second embodiment of the present invention will be explained. 
   The test site portion  20 , interconnection portion  40 , and chip carrier portion  50  are separately formed. 
   The test site portion  20  and interconnection portion  40  are adhered to each other, and part of the test element  22  and the bump  47  are electrically connected to each other. 
   The test site portion  20 , interconnection portion  40 , and chip carrier portion  50  are adhered to each other. Part of the test element  22  and the solder ball  61  are electrically connected via the bump  47 . 
   The performance of the test element  22  is evaluated using the solder ball  61 . 
   Although a plurality of test elements  22  are formed at the test site portion  20 , test elements  22  to be evaluated in this test method are only ones which are electrically connected to the solder ball  61 . In  FIG. 6B , the test elements  22   a  which are electrically connected to the solder balls  61  can be tested and evaluated. The test elements  22   b  which are not electrically connected to the solder balls  61  cannot be tested and evaluated. 
   In the second embodiment, similar to the first embodiment, of a plurality of test elements  22  formed on the TEG chip  10 , only test elements  22  to be tested and evaluated can be selected, tested, and evaluated. 
   According to the second embodiment, the test site portion  20 , interconnection portion  40 , and chip carrier portion  50  are separately formed and adhered. The test element  22  can be formed on the silicon substrate  21  regardless of the area occupied by the interconnection (pad)  49 . The region of the test element  22  is free from any limitations by the area of the interconnection  49 . 
   Similar to the first embodiment, the test elements  22  are classified by the type, and test elements  22  of the same type are aligned. The adhering portions of the test site portion  20  and interconnection portion  40  can be adjusted to select elements to be evaluated out of a plurality of test elements  22 . 
   The present invention is not limited to the above-described embodiment, and can be variously modified without departing from the spirit and scope of the invention in practical use. 
   For example, to evaluate heat resistance or the like, the TEG chip  10  may be packaged. 
   The layout of the test element and pad is not limited to the above-described one, and may be the following one. For example, as shown in  FIG. 11 , the test elements  22  may be surrounded by the pads  37 . Alternatively, as shown in  FIG. 12 , the test elements  22  may be surrounded by the pads  37  in a U shape. 
   Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.

Technology Category: h